Effects of cannabis on the brain

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Cannabis (/ˈkænÉ™bɪs/),^[2] commonly known as marijuana (/ËŒmærəˈwɑːnÉ™/),^[3] weed, and pot, among other names, is a non-chemically uniform drug from the Cannabis plant. Native to Central or South Asia, cannabis has been used as a drug for both recreational and entheogenic purposes and in various traditional medicines for centuries. Tetrahydrocannabinol (THC) is the main psychoactive component of cannabis, which is one of the 483 known compounds in the plant, including at least 65 other cannabinoids, such as cannabidiol (CBD). Cannabis can be used by smoking, vaporizing, within food, or as an extract.

Cannabis has various mental and physical effects, which include euphoria, altered states of mind and sense of time, difficulty concentrating, impaired short-term memory, impaired body movement (balance and fine psychomotor control), relaxation, and an increase in appetite. Onset of effects is felt within minutes when smoked, but may take up to 90 minutes when eaten (as orally consumed drugs must be digested and absorbed). The effects last for two to six hours, depending on the amount used. At high doses, mental effects can include anxiety, delusions (including ideas of reference), hallucinations, panic, paranoia, and psychosis. There is a strong relation between cannabis use and the risk of psychosis, though the direction of causality is debated. Physical effects include increased heart rate, difficulty breathing, nausea, and behavioral problems in children whose mothers used cannabis during pregnancy; short-term side effects may also include dry mouth and red eyes. Long-term adverse effects may include addiction, decreased mental ability in those who started regular use as adolescents,^[4] chronic coughing, susceptibility to respiratory infections, and cannabinoid hyperemesis syndrome.

Cannabis is mostly used recreationally or as a medicinal drug, although it may also be used for spiritual purposes. In 2013, between 128 and 232 million people used cannabis (2.7% to 4.9% of the global population between the ages of 15 and 65). It is the most commonly used largely-illegal drug in the world, with the highest use among adults in Zambia, the United States, Canada, and Nigeria. Since the 1970s, the potency of illicit cannabis has increased, with THC levels rising and CBD levels dropping.

Cannabis plants have been grown since at least the 3rd millennium BCE and there is evidence of it being smoked for its psychoactive effects around 500 BCE in the Pamir Mountains, Central Asia. Since the 14th century, cannabis has been subject to legal restrictions. The possession, use, and cultivation of cannabis has been illegal in most countries since the 20th century. In 2013, Uruguay became the first country to legalize recreational use of cannabis. Other countries to do so are Canada, Georgia, Germany, Luxembourg, Malta, South Africa, and Thailand. In the U.S., the recreational use of cannabis is legalized in 24 states, 3 territories, and the District of Columbia, though the drug remains federally illegal. In Australia, it is legalized only in the Australian Capital Territory.

Cannabis is a Scythian word.^[5][6][7] The ancient Greeks learned of the use of cannabis by observing Scythian funerals, during which cannabis was consumed.^[6] In Akkadian, cannabis was known as qunubu (𐎯𐎫𐎠𐎭𐏂).^[6] The word was adopted in to the Hebrew as qaneh bosem (קָנֶה בֹּשׂם).^[6]

Medical cannabis, or medical marijuana, refers to the use of cannabis to treat disease or improve symptoms; however, there is no single agreed-upon definition (e.g., cannabinoids derived from cannabis and synthetic cannabinoids are also used).^[8][9][10] The rigorous scientific study of cannabis as a medicine has been hampered by production restrictions and by the fact that it is classified as an illegal drug by many governments.^[11] There is some evidence suggesting cannabis can be used to reduce nausea and vomiting during chemotherapy, to improve appetite in people with HIV/AIDS, or to treat chronic pain and muscle spasms. Evidence for its use for other medical applications is insufficient for drawing conclusions about safety or efficacy.^[12][13][14] There is evidence supporting the use of cannabis or its derivatives in the treatment of chemotherapy-induced nausea and vomiting, neuropathic pain, and multiple sclerosis. Lower levels of evidence support its use for AIDS wasting syndrome, epilepsy, rheumatoid arthritis, and glaucoma.^[15]

The medical use of cannabis is legal only in a limited number of territories, including Canada,^[16] Belgium, Australia, the Netherlands, New Zealand,^[17][18] Spain, and many U.S. states. This usage generally requires a prescription, and distribution is usually done within a framework defined by local laws.^[15]

According to DEA Chief Administrative Law Judge, Francis Young, "cannabis is one of the safest therapeutically active substances known to man".^[19] Being under the effects of cannabis is usually referred to as being "high".^[20] Cannabis consumption has both psychoactive and physiological effects.^[21] The "high" experience can vary widely, based (among other things) on the user's prior experience with cannabis, and the type of cannabis consumed.^{[22]: p647 } When smoking cannabis, a euphoriant effect can occur within minutes of smoking.^{[23]: p104 } Aside from a subjective change in perception and mood, the most common short-term physical and neurological effects include increased heart rate, increased appetite, impairment of short-term and working memory, and impairment of psychomotor coordination.^[24][25]

Additional desired effects from consuming cannabis include relaxation, a general alteration of conscious perception, increased awareness of sensation, increased libido^[26] and distortions in the perception of time and space. At higher doses, effects can include altered body image, auditory or visual illusions, pseudohallucinations and ataxia from selective impairment of polysynaptic reflexes.^{[citation needed]} In some cases, cannabis can lead to dissociative states such as depersonalization^[27][28] and derealization.^[29]

Cannabis has held sacred status in several religions and has served as an entheogen – a chemical substance used in religious, shamanic, or spiritual contexts^[30] – in the Indian subcontinent since the Vedic period. The earliest known reports regarding the sacred status of cannabis in the Indian subcontinent come from the Atharva Veda, estimated to have been composed sometime around 1400 BCE.^[31] The Hindu god Shiva is described as a cannabis user, known as the "Lord of bhang".^{[32]: p19 }

In modern culture, the spiritual use of cannabis has been spread by the disciples of the Rastafari movement who use cannabis as a sacrament and as an aid to meditation.^[31]

Many different ways to consume cannabis involve heat to decarboxylate THCA into THC;^[33][34] common modes include:

• Smoking, involves burning and inhaling cannabinoids ("smoke") from small pipes, bongs (portable versions of hookahs with a water chamber), paper-wrapped joints, tobacco-leaf-wrapped blunts, or the like.^[35]
• Vaporizing, heating various forms of cannabis to 165–190 °C (329–374 °F),^[36] causing the active ingredients to form vapor without combustion of the plant material (the boiling point of THC is 157 °C (315 °F) at atmospheric pressure).^[37]
• Edibles, adding cannabis as an ingredient to a wide variety of foods, including butter and baked goods. In India it is commonly consumed as the beverage bhang.
• Cannabis tea, prepared with attention to the lipophilic quality of THC, which is only slightly water-soluble (2.8 mg per liter),^[38] often involving cannabis in a saturated fat.^[39]
• Tincture of cannabis, sometimes known as green dragon, is an alcoholic cannabis concentrate.
• Capsules, typically containing cannabis oil, and other dietary supplement products, for which some 220 were approved in Canada in 2018.^[16]

Global estimates of drug users in 2016
(in millions of users)^[40]

Substance	Best estimate	Low estimate	High estimate
Amphetamine- type stimulants	34.16	13.42	55.24
Cannabis	192.15	165.76	234.06
Cocaine	18.20	13.87	22.85
Ecstasy	20.57	8.99	32.34
Opiates	19.38	13.80	26.15
Opioids	34.26	27.01	44.54

In 2013, between 128 and 232 million people used cannabis (2.7% to 4.9% of the global population between the ages of 15 and 65).^[41] Cannabis is by far the most widely used illicit substance,^[42] with the highest use among adults (as of 2018^[update]) in Zambia, the United States, Canada, and Nigeria.^[43]

Between 1973 and 1978, eleven states decriminalized marijuana.^[44] In 2001, Nevada reduced marijuana possession to a misdemeanor and since 2012, several other states have decriminalized and even legalized marijuana.^[44]

In 2018, surveys indicated that almost half of the people in the United States had tried marijuana, 16% had used it in the past year, and 11% had used it in the past month.^[45] In 2014, surveys said daily marijuana use amongst US college students had reached its highest level since records began in 1980, rising from 3.5% in 2007 to 5.9% in 2014 and had surpassed daily cigarette use.^[46]

In the US, men are over twice as likely to use marijuana as women, and 18–29-year-olds are six times more likely to use as over-65-year-olds.^[47] In 2015, a record 44% of the US population has tried marijuana in their lifetime, an increase from 38% in 2013 and 33% in 1985.^[47]

Marijuana use in the United States is three times above the global average, but in line with other Western democracies. Forty-four percent of American 12th graders have tried the drug at least once, and the typical age of first-use is 16, similar to the typical age of first-use for alcohol but lower than the first-use age for other illicit drugs.^[42]

A 2022 Gallup poll concluded Americans are smoking more marijuana than cigarettes for the first time.^[48]

Acute negative effects may include anxiety and panic, impaired attention and memory, an increased risk of psychotic symptoms,^[b] the inability to think clearly, and an increased risk of accidents.^[51][52][53] Cannabis impairs a person's driving ability, and THC was the illicit drug most frequently found in the blood of drivers who have been involved in vehicle crashes. Those with THC in their system are from three to seven times more likely to be the cause of the accident than those who had not used either cannabis or alcohol, although its role is not necessarily causal because THC stays in the bloodstream for days to weeks after intoxication.^[54][55][c]

Some immediate undesired side effects include a decrease in short-term memory, dry mouth, impaired motor skills, reddening of the eyes,^[58] dizziness, feeling tired and vomiting.^[13] Some users may experience an episode of acute psychosis, which usually abates after six hours, but in rare instances, heavy users may find the symptoms continuing for many days.^[59]

Legalization has increased the rates at which children are exposed to cannabis, particularly from edibles. While the toxicity and lethality of THC in children is not known, they are at risk for encephalopathy, hypotension, respiratory depression severe enough to require ventilation, somnolence and coma.^[60][61]

There is no clear evidence for a link between cannabis use and deaths from cardiovascular disease, but a 2019 review noted that it may be an under-reported, contributory factor or direct cause in cases of sudden death, due to the strain it can place on the cardiovascular system. Some deaths have also been attributed to cannabinoid hyperemesis syndrome.^[62] There is an association between cannabis use and suicide, particularly in younger users.^[63]

A 16-month survey of Oregon and Alaska emergency departments found a report of the death of an adult who had been admitted for acute cannabis toxicity.^[64]

A recent study in 2025 suggests that individuals diagnosed with cannabis use disorder—characterized by an inability to stop using cannabis despite its negative effects—face a nearly threefold increase in mortality rates compared to those without the condition over a five-year period.^[65] The research indicates that people with this disorder are ten times more likely to die by suicide than the general population.^[66] Additionally, they have a higher risk of death from trauma, drug poisoning, and lung cancer. In a separate study researchers found an increase in schizophrenia and psychosis cases in Canada linked to cannabis use disorder following the drug’s legalization.^[67]

A 2015 meta-analysis found that, although a longer period of abstinence was associated with smaller magnitudes of impairment, both retrospective and prospective memory were impaired in cannabis users. The authors concluded that some, but not all, of the deficits associated with cannabis use were reversible.^[69] A 2012 meta-analysis found that deficits in most domains of cognition persisted beyond the acute period of intoxication, but was not evident in studies where subjects were abstinent for more than 25 days.^[70] Few high quality studies have been performed on the long-term effects of cannabis on cognition, and the results were generally inconsistent.^[71] Furthermore, effect sizes of significant findings were generally small.^[70] One review concluded that, although most cognitive faculties were unimpaired by cannabis use, residual deficits occurred in executive functions.^[72] Impairments in executive functioning are most consistently found in older populations, which may reflect heavier cannabis exposure, or developmental effects associated with adolescent cannabis use.^[73] One review found three prospective cohort studies that examined the relationship between self-reported cannabis use and intelligence quotient (IQ). The study following the largest number of heavy cannabis users reported that IQ declined between ages 7–13 and age 38. Poorer school performance and increased incidence of leaving school early were both associated with cannabis use, although a causal relationship was not established.^[74] Cannabis users demonstrated increased activity in task-related brain regions, consistent with reduced processing efficiency.^[75]

A reduced quality of life is associated with heavy cannabis use, although the relationship is inconsistent and weaker than for tobacco and other substances.^[76] The direction of cause and effect, however, is unclear.^[76]

The long-term effects of cannabis are not clear.^[13] There are concerns surrounding memory and cognition problems, risk of addiction, and the risk of schizophrenia in young people.^[12]

Although global abnormalities in white matter and grey matter are not consistently associated with cannabis use,^[77] reduced hippocampal volume is consistently found.^[78] Amygdala abnormalities are sometimes reported, although findings are inconsistent.^[79][80][81]

Cannabis use is associated with increased recruitment of task-related areas, such as the dorsolateral prefrontal cortex, which is thought to reflect compensatory activity due to reduced processing efficiency.^[81][80][82] Cannabis use is also associated with downregulation of CB₁ receptors. The magnitude of down regulation is associated with cumulative cannabis exposure, and is reversed after one month of abstinence.^[74][83][84] There is limited evidence that chronic cannabis use can reduce levels of glutamate metabolites in the human brain.^[85]

About 9% of those who experiment with marijuana eventually become dependent according to DSM-IV (1994) criteria.^[15] A 2013 review estimates daily use is associated with a 10–20% rate of dependence.^[12] The highest risk of cannabis dependence is found in those with a history of poor academic achievement, deviant behavior in childhood and adolescence, rebelliousness, poor parental relationships, or a parental history of drug and alcohol problems.^[86] Of daily users, about 50% experience withdrawal upon cessation of use (i.e. are dependent), characterized by sleep problems, irritability, dysphoria, and craving.^[74] Cannabis withdrawal is less severe than withdrawal from alcohol.^[87]

According to DSM-V criteria, 9% of those who are exposed to cannabis develop cannabis use disorder, compared to 20% for cocaine, 23% for alcohol and 68% for nicotine. Cannabis use disorder in the DSM-V involves a combination of DSM-IV criteria for cannabis abuse and dependence, plus the addition of craving, without the criterion related to legal troubles.^[74]

From a clinical perspective, two significant school of thought exists for psychiatric conditions associated with cannabis (or cannabinoids) use: transient, non-persistent psychotic reactions, and longer-lasting, persistent disorders that resemble schizophrenia. The former is formally known as acute cannabis-associated psychotic symptoms (CAPS).^[88]

At an epidemiological level, a dose–response relationship exists between cannabis use and increased risk of psychosis and earlier onset of psychosis.^{[89][90][91][92][93]} Although the epidemiological association is robust, evidence to prove a causal relationship is lacking.^[94]

Cannabis may also increase the risk of depression, but insufficient research has been performed to draw a conclusion.^[95][91] Cannabis use is associated with increased risk of anxiety disorders, although causality has not been established.^[96]

A review in 2019 found that research was insufficient to determine the safety and efficacy of using cannabis to treat schizophrenia, psychosis, or other mental disorders.^[97][98] Another found that cannabis during adolescence was associated with an increased risk of developing depression and suicidal behavior later in life, while finding no effect on anxiety.^[99]

Heavy, long-term exposure to marijuana may have physical, mental, behavioral and social health consequences. It may be "associated with diseases of the liver (particularly with co-existing hepatitis C), lungs, heart, and vasculature".^[100] A 2014 review found that while cannabis use may be less harmful than alcohol use, the recommendation to substitute it for problematic drinking was premature without further study.^[101] Various surveys conducted between 2015 and 2019 found that many users of cannabis substitute it for prescription drugs (including opioids), alcohol, and tobacco; most of those who used it in place of alcohol or tobacco either reduced or stopped their intake of the latter substances.^[102]

Cannabinoid hyperemesis syndrome (CHS) is a severe condition seen in some chronic cannabis users where they have repeated bouts of uncontrollable vomiting for 24–48 hours. Four cases of death have been reported as a result of CHS.^[103][104]

A limited number of studies have examined the effects of cannabis smoking on the respiratory system.^[105] Chronic heavy marijuana smoking is associated with respiratory infections,^[106] coughing, production of sputum, wheezing, and other symptoms of chronic bronchitis.^[51] The available evidence does not support a causal relationship between cannabis use and chronic obstructive pulmonary disease.^[107] Short-term use of cannabis is associated with bronchodilation.^[108] Other side effects of cannabis use include cannabinoid hyperemesis syndrome (CHS), a condition which involves recurrent nausea, cramping abdominal pain, and vomiting.^[109]

Cannabis smoke contains thousands of organic and inorganic chemical compounds. This tar is chemically similar to that found in tobacco smoke,^[110] and over fifty known carcinogens have been identified in cannabis smoke,^[111] including; nitrosamines, reactive aldehydes, and polycyclic aromatic hydrocarbons, including benz[a]pyrene.^[112] Cannabis smoke is also inhaled more deeply than tobacco smoke.^[113] As of 2015^[update], there is no consensus regarding whether cannabis smoking is associated with an increased risk of cancer.^[114] Light and moderate use of cannabis is not believed to increase risk of lung or upper airway cancer. Evidence for causing these cancers is mixed concerning heavy, long-term use. In general there are far lower risks of pulmonary complications for regular cannabis smokers when compared with those of tobacco.^[115] A 2015 review found an association between cannabis use and the development of testicular germ cell tumors (TGCTs), particularly non-seminoma TGCTs.^[116] Another 2015 meta-analysis found no association between lifetime cannabis use and risk of head or neck cancer.^[117] Combustion products are not present when using a vaporizer, consuming THC in pill form, or consuming cannabis foods.^[118]

There is concern that cannabis may contribute to cardiovascular disease,^[119] but as of 2018^[update], evidence of this relationship was unclear.^[120] Research in these events is complicated because cannabis is often used in conjunction with tobacco, and drugs such as alcohol and cocaine that are known to have cardiovascular risk factors.^[121] Smoking cannabis has also been shown to increase the risk of myocardial infarction by 4.8 times for the 60 minutes after consumption.^[122]

There is preliminary evidence that cannabis interferes with the anticoagulant properties of prescription drugs used for treating blood clots.^[123] As of 2019^[update], the mechanisms for the anti-inflammatory and possible pain relieving effects of cannabis were not defined, and there were no governmental regulatory approvals or clinical practices for use of cannabis as a drug.^[98]

Emergency room (ER) admissions associated with cannabis use rose significantly from 2012 to 2016; adolescents from age 12–17 had the highest risk.^[124] At one Colorado medical center following legalization, approximately two percent of ER admissions were classified as cannabis users. The symptoms of one quarter of these users were partially attributed to cannabis (a total of 2567 out of 449,031 patients); other drugs were sometimes involved. Of these cannabis admissions, one quarter were for acute psychiatric effects, primarily suicidal ideation, depression, and anxiety. An additional third of the cases were for gastrointestinal issues including cannabinoid hyperemesis syndrome.^[125]

According to the United States Department of Health and Human Services, there were 455,000 emergency room visits associated with cannabis use in 2011. These statistics include visits in which the patient was treated for a condition induced by or related to recent cannabis use. The drug use must be "implicated" in the emergency department visit, but does not need to be the direct cause of the visit. Most of the illicit drug emergency room visits involved multiple drugs.^[126] In 129,000 cases, cannabis was the only implicated drug.^[126][15]

A 2022 study found that smoking cannabis using a bong can greatly increase background levels of fine particulate matter, a carcinogen, in an enclosed space such as a living room. After 15 minutes, mean levels of particulate matter were more than twice the Environmental Protection Agency hazardous air quality threshold, and after 140 minutes, the concentrations were four times greater than those generated by smoking tobacco using a cigarette or hookah. This suggests secondhand cannabis smoke from bongs may present a health risk to non-smokers.^[128]

THC is a weak partial agonist at CB₁ receptors, while CBD is a CB₁ receptor antagonist.^[129][130] The CB₁ receptor is found primarily in the brain as well as in some peripheral tissues, and the CB₂ receptor is found primarily in peripheral tissues, but is also expressed in neuroglial cells.^[131] THC appears to alter mood and cognition through its agonist actions on the CB₁ receptors, which inhibit a secondary messenger system (adenylate cyclase) in a dose-dependent manner.

Via CB₁ receptor activation, THC indirectly increases dopamine release and produces psychotropic effects.^[132] CBD also acts as an allosteric modulator of the μ- and δ-opioid receptors.^[133] THC also potentiates the effects of the glycine receptors.^[134] It is unknown if or how these actions contribute to the effects of cannabis.^[135]

The high lipid-solubility of cannabinoids results in their persisting in the body for long periods of time.^[136] Even after a single administration of THC, detectable levels of THC can be found in the body for weeks or longer (depending on the amount administered and the sensitivity of the assessment method).^[136] Investigators have suggested that this is an important factor in marijuana's effects, perhaps because cannabinoids may accumulate in the body, particularly in the lipid membranes of neurons.^[137]

The main psychoactive component of cannabis is tetrahydrocannabinol (THC), which is formed via decarboxylation of tetrahydrocannabinolic acid (THCA) from the application of heat. Raw leaf is not psychoactive because the cannabinoids are in the form of carboxylic acids.^{[citation needed]} THC is one of the 483 known compounds in the plant,^[138] including at least 65 other cannabinoids,^[139] such as cannabidiol (CBD).^[53]

THC and its major (inactive) metabolite, THC-COOH, can be measured in blood, urine, hair, oral fluid or sweat using chromatographic techniques as part of a drug use testing program or a forensic investigation of a traffic or other criminal offense.^[59] The concentrations obtained from such analyses can often be helpful in distinguishing active use from passive exposure, elapsed time since use, and extent or duration of use. These tests cannot, however, distinguish authorized cannabis smoking for medical purposes from unauthorized recreational smoking.^[140] Commercial cannabinoid immunoassays, often employed as the initial screening method when testing physiological specimens for marijuana presence, have different degrees of cross-reactivity with THC and its metabolites.^[141] Urine contains predominantly THC-COOH, while hair, oral fluid and sweat contain primarily THC.^[59] Blood may contain both substances, with the relative amounts dependent on the recency and extent of usage.^[59]

The Duquenois–Levine test is commonly used as a screening test in the field, but it cannot definitively confirm the presence of cannabis, as a large range of substances have been shown to give false positives.^[142] Researchers at John Jay College of Criminal Justice reported that dietary zinc supplements can mask the presence of THC and other drugs in urine.^[143] However, a 2013 study conducted by researchers at the University of Utah School of Medicine refute the possibility of self-administered zinc producing false-negative urine drug tests.^[144]

CBD is a 5-HT_1A receptor agonist, which is under laboratory research to determine if it has an anxiolytic effect.^[145] It is often claimed that sativa strains provide a more stimulating psychoactive high while indica strains are more sedating with a body high.^[146] However, this is disputed by researchers.^[147]

A 2015 review found that the use of high CBD-to-THC strains of cannabis showed significantly fewer positive symptoms, such as delusions and hallucinations, better cognitive function and both lower risk for developing psychosis, as well as a later age of onset of the illness, compared to cannabis with low CBD-to-THC ratios.^[148]

According to the United Nations Office on Drugs and Crime (UNODC), "the amount of THC present in a cannabis sample is generally used as a measure of cannabis potency."^[149] The three main forms of cannabis products are the flower/fruit, resin (hashish), and oil (hash oil). The UNODC states that cannabis often contains 5% THC content, resin "can contain up to 20% THC content", and that "Cannabis oil may contain more than 60% THC content."^[149]

Studies have found that the potency of illicit cannabis has greatly increased since the 1970s, with THC levels rising and CBD levels dropping.^{[150][151][152]} It is unclear, however, whether the increase in THC content has caused people to consume more THC or if users adjust based on the potency of the cannabis. It is likely that the higher THC content allows people to ingest less tar. At the same time, CBD levels in seized samples have lowered, in part because of the desire to produce higher THC levels and because more illegal growers cultivate indoors using artificial lights. This helps avoid detection but reduces the CBD production of the plant.^[153]

Australia's National Cannabis Prevention and Information Centre (NCPIC) states that the buds (infructescences) of the female Cannabis plant contain the highest concentration of THC, followed by the leaves. The stalks and seeds have "much lower THC levels".^[154] The UN states that the leaves can contain ten times less THC than the buds, and the stalks 100 times less THC.^[149]

After revisions to cannabis scheduling in the UK, the government moved cannabis back from a class C to a class B drug. A purported reason was the appearance of high potency cannabis. They believe skunk accounts for between 70% and 80% of samples seized by police^[155] (despite the fact that skunk can sometimes be incorrectly mistaken for all types of herbal cannabis).^[156][157] Extracts such as hashish and hash oil typically contain more THC than high potency cannabis infructescences.^[158]

Hemp buds (or low-potency cannabis buds) laced with synthetic cannabinoids started to be sold as cannabis street drug in 2020.^{[159][160][161][162]}

The short-term effects of cannabis can be altered if it has been laced with opioid drugs such as heroin or fentanyl.^[163] The added drugs are meant to enhance the psychoactive properties, add to its weight, and increase profitability, despite the increased danger of overdose.^[164][d]

Marijuana or marihuana (herbal cannabis)^[166] consists of the dried flowers and fruits and subtending leaves and stems of the female cannabis plant.^{[167][168][169][170]} This is the most widely consumed form,^[170] containing 3% to 20% THC,^[171] with reports of up to 33% THC.^[172] This is the stock material from which all other preparations are derived. Although herbal cannabis and industrial hemp derive from the same species and contain the psychoactive component (THC), they are distinct strains with unique biochemical compositions and uses. Hemp has lower concentrations of THC and higher concentrations of CBD, which gives lesser psychoactive effects.^[173][174]

Kief is a powder, rich in trichomes,^[175] which can be sifted from the leaves, flowers and fruits of cannabis plants and either consumed in powder form or compressed to produce cakes of hashish.^[176] The word "kif" derives from colloquial Arabic كيف kēf/kīf, meaning pleasure.^[177]

Hashish (also spelled hasheesh, hashisha, or simply hash) is a concentrated resin cake or ball produced from pressed kief, the detached trichomes and fine material that falls off cannabis fruits, flowers and leaves,^[178] or from scraping the resin from the surface of the plants and rolling it into balls. It varies in color from black to golden brown depending upon purity and variety of cultivar it was obtained from.^[179] It can be consumed orally or smoked, and is also vaporized, or 'vaped'.^[180] The term "rosin hash" refers to a high quality solventless product obtained through heat and pressure.^[181]

Cannabinoids can be extracted from cannabis plant matter using high-proof spirits (often grain alcohol) to create a tincture, often referred to as "green dragon".^{[32]: p17 } Nabiximols is a branded product name from a tincture manufacturing pharmaceutical company.^[182]

Hash oil is a resinous matrix of cannabinoids obtained from the cannabis plant by solvent extraction,^[183] formed into a hardened or viscous mass.^[184] Hash oil can be the most potent of the main cannabis products because of its high level of psychoactive compound per its volume, which can vary depending on the plant's mix of essential oils and psychoactive compounds.^[185] Butane and supercritical carbon dioxide hash oil have become popular in recent years.^[186]

There are many varieties of cannabis infusions owing to the variety of non-volatile solvents used.^[187] The plant material is mixed with the solvent and then pressed and filtered to express the oils of the plant into the solvent. Examples of solvents used in this process are cocoa butter, dairy butter, cooking oil, glycerine, and skin moisturizers. Depending on the solvent, these may be used in cannabis foods or applied topically.^[188]

Marihuana prensada ('pressed marijuana') is a cannabis-derived product widespread among the lower classes of South America,^[189] especially from the 90s. Locally it is known as "paraguayo" or "paragua", since its main producer is Paraguay.^[190] Marijuana is dried and mixed with binding agents that make it toxic and highly harmful to health.^[191] It is cut into the shape of bricks (ladrillos) and sold for a low price in Argentina, Brazil, Chile, Peru, Venezuela, and even the United States.^[192]

Cannabis is indigenous to Central or South Asia^[193] and its uses for fabric and rope dates back to the Neolithic age in China and Japan.^[194][195] It is unclear when cannabis first became known for its psychoactive properties. The oldest archeological evidence for the burning of cannabis was found in Romanian kurgans dated 3,500 BC, and scholars suggest that the drug was first used in ritual ceremonies by Proto-Indo-European tribes living in the Pontic-Caspian steppe during the Chalcolithic period, a custom they eventually spread throughout Western Eurasia during the Indo-European migrations.^[196][197] Some research suggests that the ancient Indo-Iranian drug soma, mentioned in the Vedas, sometimes contained cannabis. This is based on the discovery of a basin containing cannabis in a shrine of the second millennium BC in Turkmenistan.^[198]

Cannabis was known to the ancient Assyrians, who discovered its psychoactive properties through the Iranians.^[199] Using it in some religious ceremonies, they called it qunubu (meaning "way to produce smoke"), a probable origin of the modern word cannabis.^[200] The Iranians also introduced cannabis to the Scythians, Thracians and Dacians, whose shamans (the kapnobatai – "those who walk on smoke/clouds") burned cannabis infructescences to induce trance.^[201] The plant was used in China before 2800 BC, and found therapeutic use in India by 1000 BC, where it was used in food and drink, including bhang.^[202][203]

Cannabis has an ancient history of ritual use and has been used by religions around the world. It has been used as a drug for both recreational and entheogenic purposes and in various traditional medicines for centuries.^{[204][205][166]} The earliest evidence of cannabis smoking has been found in the 2,500-year-old tombs of Jirzankal Cemetery in the Pamir Mountains in Western China, where cannabis residue were found in burners with charred pebbles possibly used during funeral rituals.^[206][207] Hemp seeds discovered by archaeologists at Pazyryk suggest early ceremonial practices like eating by the Scythians occurred during the 5th to 2nd century BC, confirming previous historical reports by Herodotus.^[208] It was used by Muslims in various Sufi orders as early as the Mamluk period, for example by the Qalandars.^[209] Smoking pipes uncovered in Ethiopia and carbon-dated to around c. AD 1320 were found to have traces of cannabis.^[210]

Cannabis was introduced to the New World by the Spaniards in 1530–1545.^{[211][212][213]} Following an 1836–1840 travel in North Africa and the Middle East, French physician Jacques-Joseph Moreau wrote on the psychological effects of cannabis use; he founded the Paris' Club des Hashischins in 1844.^[214] In 1842, Irish physician William Brooke O'Shaughnessy, who had studied the drug while working as a medical officer in Bengal with the East India Company, brought a quantity of cannabis with him on his return to Britain, provoking renewed interest in the West.^[215] Examples of classic literature of the period featuring cannabis include Les paradis artificiels (1860) by Charles Baudelaire and The Hasheesh Eater (1857) by Fitz Hugh Ludlow.

Cannabis was criminalized in some countries beginning in the 14th century and was illegal in most countries by the middle of the 20th century. The colonial government of Mauritius banned cannabis in 1840 over concerns on its effect on Indian indentured workers;^[216] the same occurred in Singapore in 1870.^[217] In the United States, the first restrictions on sale of cannabis came in 1906 (in the District of Columbia).^[218] Canada criminalized cannabis in The Opium and Narcotic Drug Act, 1923,^[219] before any reports of the use of the drug in Canada, but eventually legalized its consumption for recreational and medicinal purposes in 2018.^[16]

In 1925, a compromise was made at an international conference in The Hague about the International Opium Convention that banned exportation of "Indian hemp" to countries that had prohibited its use, and requiring importing countries to issue certificates approving the importation and stating that the shipment was required "exclusively for medical or scientific purposes". It also required parties to "exercise an effective control of such a nature as to prevent the illicit international traffic in Indian hemp and especially in the resin".^[220][221] In the United States in 1937, the Marihuana Tax Act was passed,^[222] and prohibited the production of hemp in addition to cannabis.

In 1972, the Dutch government divided drugs into more- and less-dangerous categories, with cannabis being in the lesser category. Accordingly, possession of 30 grams (1.1 oz) or less was made a misdemeanor.^[223] Cannabis has been available for recreational use in coffee shops since 1976.^[224] Cannabis products are only sold openly in certain local "coffeeshops" and possession of up to 5 grams (0.18 oz) for personal use is decriminalized, however: the police may still confiscate it, which often happens in car checks near the border. Other types of sales and transportation are not permitted, although the general approach toward cannabis was lenient even before official decriminalization.^{[225][226][227]}

In Uruguay, President Jose Mujica signed legislation to legalize recreational cannabis in December 2013, making Uruguay the first country in the modern era to legalize cannabis. In August 2014, Uruguay legalized growing up to six plants at home, as well as the formation of growing clubs (Cannabis social club), and a state-controlled marijuana dispensary regime.

As of 17 October 2018^[update], when recreational use of cannabis was legalized in Canada, dietary supplements for human use and veterinary health products containing not more than 10 parts per million of THC extract were approved for marketing; Nabiximols (as Sativex) is used as a prescription drug in Canada.^[16]

The United Nations' World Drug Report stated that cannabis "was the world's most widely produced, trafficked, and consumed drug in the world in 2010", and estimated between 128 million and 238 million users globally in 2015.^[228][229]

Cannabis has been one of the most used psychoactive drugs in the world since the late 20th century, following only tobacco and alcohol in popularity.^[231] According to Vera Rubin, the use of cannabis has been encompassed by two major cultural complexes over time: a continuous, traditional folk stream, and a more circumscribed, contemporary configuration.^[232] The former involves both sacred and secular use, and is usually based on small-scale cultivation: the use of the plant for cordage, clothing, medicine, food, and a "general use as an euphoriant and symbol of fellowship."^[232][233] The second stream of expansion of cannabis use encompasses "the use of hemp for commercial manufacturers utilizing large-scale cultivation primarily as a fiber for mercantile purposes"; but it is also linked to the search for psychedelic experiences (which can be traced back to the formation of the Parisian Club des Hashischins).^[233]

---

See also countries that have legalized medical use of cannabis.

Since the beginning of the 20th century, most countries have enacted laws against the cultivation, possession or transfer of cannabis.^[234] These laws have had an adverse effect on cannabis cultivation for non-recreational purposes, but there are many regions where handling of cannabis is legal or licensed. Many jurisdictions have lessened the penalties for possession of small quantities of cannabis so that it is punished by confiscation and sometimes a fine, rather than imprisonment, focusing more on those who traffic the drug on the black market.

In some areas where cannabis use had been historically tolerated, new restrictions were instituted, such as the closing of cannabis coffee shops near the borders of the Netherlands,^[235] and closing of coffee shops near secondary schools in the Netherlands.^[236] In Copenhagen, Denmark in 2014, mayor Frank Jensen discussed possibilities for the city to legalize cannabis production and commerce.^[237]

Some jurisdictions use free voluntary or mandatory treatment programs for frequent known users. Simple possession can carry long prison terms in some countries, particularly in East Asia, where the sale of cannabis may lead to a sentence of life in prison or even execution. Political parties, non-profit organizations, and causes based on the legalization of medical cannabis or legalizing the plant entirely (with some restrictions) have emerged in such countries as China and Thailand.^[238][239]

In December 2012, the U.S. state of Washington became the first state to officially legalize cannabis in a state law (Washington Initiative 502) (but still illegal by federal law),^[240] with the state of Colorado following close behind (Colorado Amendment 64).^[241] On 1 January 2013, the first cannabis "club" for private marijuana smoking (no buying or selling, however) was allowed for the first time in Colorado.^[242] The California Supreme Court decided in May 2013 that local governments can ban medical cannabis dispensaries despite a state law in California that permits the use of cannabis for medical purposes. At least 180 cities across California have enacted bans in recent years.^[243]

On 30 April 2024, the United States Department of Justice announced it would move to reclassify cannabis from a Schedule I to a Schedule III controlled substance.^[244][245]

In December 2013, Uruguay became the first country to legalize growing, sale and use of cannabis.^[246] After a long delay in implementing the retail component of the law, in 2017 sixteen pharmacies were authorized to sell cannabis commercially.^[247] On 19 June 2018, the Canadian Senate passed a bill and the Prime Minister announced the effective legalization date as 17 October 2018.^[16][248] Canada is the second country to legalize the drug.^[249]

In November 2015, Uttarakhand became the first state of India to legalize the cultivation of hemp for industrial purposes.^[250] Usage within the Hindu and Buddhist cultures of the Indian subcontinent is common, with many street vendors in India openly selling products infused with cannabis, and traditional medical practitioners in Sri Lanka selling products infused with cannabis for recreational purposes and well as for religious celebrations.^[251] Indian laws criminalizing cannabis date back to the colonial period. India and Sri Lanka have allowed cannabis to be taken in the context of traditional culture for recreational/celebratory purposes and also for medicinal purposes.^[251]

On 17 October 2015, Australian health minister Sussan Ley presented a new law that will allow the cultivation of cannabis for scientific research and medical trials on patients.^[252]

On 17 October 2018, Canada legalized cannabis for recreational adult use^[253] making it the second country in the world to do so after Uruguay and the first G7 nation.^[254] This legalization comes with regulation similar to that of alcohol in Canada, age restrictions, limiting home production, distribution, consumption areas and sale times.^[255] Laws around use vary from province to province including age limits, retail structure, and growing at home.^[253] The Canadian Licensed Producer system aims to become the Gold Standard in the world for safe and secure cannabis production,^[256] including provisions for a robust craft cannabis industry where many expect opportunities for experimenting with different strains.^[257]

As the drug has increasingly been seen as a health issue instead of criminal behavior, cannabis has also been legalized or decriminalized in: Czech Republic,^[258] Colombia,^[259][260] Ecuador,^{[261][262][263]} Portugal,^[264] South Africa^[265] and Canada.^[16] Medical marijuana was legalized in Mexico in mid-2017 and legalized for recreational use in June 2021.^{[266][267][268]}

Germany legalized cannabis for recreational use in April 2024.^[269]

As of 2022, Uruguay and Canada are the only countries that have fully legalized the cultivation, consumption and bartering of recreational cannabis nationwide.^[270][271] In the United States, 24 states, 3 territories, and the District of Columbia have legalized the recreational use of cannabis – though the drug remains illegal at the federal level.^[272] Laws vary from state to state when it comes to the commercial sale. Court rulings in Georgia and South Africa have led to the legalization of cannabis consumption, but not legal sales. A policy of limited enforcement has also been adopted in many countries, in particular Spain and the Netherlands where the sale of cannabis is tolerated at licensed establishments.^[273][274] Contrary to popular belief, cannabis is not legal in the Netherlands,^[275] but it has been decriminalized since the 1970s. In 2021, Malta was the first European Union member to legalize the use of cannabis for recreational purposes.^[276] In Estonia, it is only legal to sell cannabis products with a THC content of less than 0.2%, although products may contain more cannabidiol.^[277] Lebanon has recently become the first Arab country to legalize the plantation of cannabis for medical use.^[278]

Penalties for illegal recreational use ranges from confiscation or small fines to jail time and even death.^[279] In some countries citizens can be punished if they have used the drug in another country, including Singapore and South Korea.^[280][281]

Sinsemilla (Spanish for "without seed") is the dried, seedless (i.e. parthenocarpic) infructescences of female cannabis plants. Because THC production drops off once pollination occurs, the male plants (which produce little THC themselves) are eliminated before they shed pollen to prevent pollination, thus inducing the development of parthenocarpic fruits gathered in dense infructescences. Advanced cultivation techniques such as hydroponics, cloning, high-intensity artificial lighting, and the sea of green method are frequently employed as a response (in part) to prohibition enforcement efforts that make outdoor cultivation more risky.

"Skunk" refers to several named strains of potent cannabis, grown through selective breeding and sometimes hydroponics. It is a cross-breed of Cannabis sativa and C. indica (although other strains of this mix exist in abundance). Skunk cannabis potency ranges usually from 6% to 15% and rarely as high as 20%. The average THC level in coffee shops in the Netherlands is about 18–19%.^[282]

The average levels of THC in cannabis sold in the United States rose dramatically between the 1970s and 2000.^[283] This is disputed for various reasons, and there is little consensus as to whether this is a fact or an artifact of poor testing methodologies.^[283] According to Daniel Forbes writing for slate.com, the relative strength of modern strains are likely skewed because undue weight is given to much more expensive and potent, but less prevalent, samples.^[284] Some suggest that results are skewed by older testing methods that included low-THC-content plant material such as leaves in the samples, which are excluded in contemporary tests. Others believe that modern strains actually are significantly more potent than older ones.^[283]

The main producing countries of cannabis are Afghanistan,^[285] Canada,^[286] China, Colombia,^[287] India,^[285] Jamaica,^[285] Lebanon,^[288] Mexico,^[289] Morocco,^[285] the Netherlands, Pakistan, Paraguay,^[289] Spain,^[285] Thailand, Turkey, the United Kingdom,^[290] and the United States.^[285]

The price or street value of cannabis varies widely depending on geographic area and potency.^[291] Prices and overall markets have also varied considerably over time.

• In 1997, cannabis was estimated to be overall the number four value crop in the US, and number one or two in many states, including California, New York, and Florida. This estimate is based on a value to growers of ~60% of retail value, or $3,000 per pound ($6,600/kg).^[292]
• In 2006, cannabis was estimated to have been a $36 billion market.^[293] This estimate has been challenged as exaggerated.^[42] The UN World Drug Report (2008) estimated that 2006 street prices in the US and Canada ranged from about US$8.8 to $25 per gram (approximately $250 to $700 per ounce), depending on quality.^[294] Typical U.S. retail prices were $10–15 per gram (approximately $280–420 per ounce).
• In 2017, the U.S. was estimated to constitute 90% of the worldwide $9.5 billion legal trade in cannabis.^[295]

After some U.S. states legalized cannabis, street prices began to drop. In Colorado, the price of smokable buds (infructescences) dropped 40 percent between 2014 and 2019, from $200 per ounce to $120 per ounce ($7 per gram to $4.19 per gram).^[296]

The European Monitoring Centre for Drugs and Drug Addiction reports that typical retail prices in Europe for cannabis varied from €2 to €20 per gram in 2008, with a majority of European countries reporting prices in the range €4–10.^[297]

The gateway hypothesis states that cannabis use increases the probability of trying "harder" drugs. The hypothesis has been hotly debated as it is regarded by some as the primary rationale for the United States prohibition on cannabis use.^[298][299] A Pew Research Center poll found that political opposition to marijuana use was significantly associated with concerns about the health effects and whether legalization would increase cannabis use by children.^[300]

Some studies state that while there is no proof for the gateway hypothesis,^[301] young cannabis users should still be considered as a risk group for intervention programs.^[302] Other findings indicate that hard drug users are likely to be poly-drug users, and that interventions must address the use of multiple drugs instead of a single hard drug.^[303] Almost two-thirds of the poly drug users in the 2009–2010 Scottish Crime and Justice Survey used cannabis.^[304]

The gateway effect may appear due to social factors involved in using any illegal drug. Because of the illegal status of cannabis, its consumers are likely to find themselves in situations allowing them to acquaint with individuals using or selling other illegal drugs.^[305][306] Studies have shown that alcohol and tobacco may additionally be regarded as gateway drugs;^[307] however, a more parsimonious explanation could be that cannabis is simply more readily available (and at an earlier age) than illegal hard drugs.^{[citation needed]} In turn, alcohol and tobacco are typically easier to obtain at an earlier age than is cannabis (though the reverse may be true in some areas), thus leading to the "gateway sequence" in those individuals, since they are most likely to experiment with any drug offered.^[298]

A related alternative to the gateway hypothesis is the common liability to addiction (CLA) theory. It states that some individuals are, for various reasons, willing to try multiple recreational substances. The "gateway" drugs are merely those that are (usually) available at an earlier age than the harder drugs. Researchers have noted in an extensive review that it is dangerous to present the sequence of events described in gateway "theory" in causative terms as this hinders both research and intervention.^[308]

In 2020, the National Institute on Drug Abuse released a study backing allegations that marijuana is a gateway to harder drugs, though not for the majority of marijuana users.^[309] The National Institute on Drug Abuse determined that marijuana use is "likely to precede use of other licit and illicit substances" and that "adults who reported marijuana use during the first wave of the survey were more likely than adults who did not use marijuana to develop an alcohol use disorder within 3 years; people who used marijuana and already had an alcohol use disorder at the outset were at greater risk of their alcohol use disorder worsening. Marijuana use is also linked to other substance use disorders including nicotine addiction."^[309] It also reported that "These findings are consistent with the idea of marijuana as a "gateway drug". However, the majority of people who use marijuana do not go on to use other, "harder" substances. Also, cross-sensitization is not unique to marijuana. Alcohol and nicotine also prime the brain for a heightened response to other drugs and are, like marijuana, also typically used before a person progresses to other, more harmful substances."^[309]

Research on cannabis is challenging since the plant is illegal in most countries.^{[310][311][312][313][314]} Research-grade samples of the drug are difficult to obtain for research purposes, unless granted under authority of national regulatory agencies, such as the US Food and Drug Administration.^[315]

There are also other difficulties in researching the effects of cannabis. Many people who smoke cannabis also smoke tobacco.^[316] This causes confounding factors, where questions arise as to whether the tobacco, the cannabis, or both that have caused a cancer. Another difficulty researchers have is in recruiting people who smoke cannabis into studies. Because cannabis is an illegal drug in many countries, people may be reluctant to take part in research, and if they do agree to take part, they may not say how much cannabis they actually smoke.^[317]

• Cannabis rights
• Glossary of cannabis terms
• List of books about cannabis
• List of celebrities who own cannabis businesses

Footnotes

Citations

• Media related to Cannabis at Wikimedia Commons
• The dictionary definition of marijuana at Wiktionary

 

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Cannabis (/ˈkænÉ™bɪs/)^[2] is a genus of flowering plants in the family Cannabaceae that is widely accepted as being indigenous to and originating from the continent of Asia.^[3][4][5] However, the number of species is disputed, with as many as three species being recognized: Cannabis sativa, C. indica, and C. ruderalis. Alternatively, C. ruderalis may be included within C. sativa, or all three may be treated as subspecies of C. sativa,^[1][6][7][8] or C. sativa may be accepted as a single undivided species.^[9]

The plant is also known as hemp, although this term is usually used to refer only to varieties cultivated for non-drug use. Hemp has long been used for fibre, seeds and their oils, leaves for use as vegetables, and juice. Industrial hemp textile products are made from cannabis plants selected to produce an abundance of fibre.

Cannabis also has a long history of being used for medicinal purposes, and as a recreational drug known by several slang terms, such as marijuana, pot or weed. Various cannabis strains have been bred, often selectively to produce high or low levels of tetrahydrocannabinol (THC), a cannabinoid and the plant's principal psychoactive constituent. Compounds such as hashish and hash oil are extracted from the plant.^[10] More recently, there has been interest in other cannabinoids like cannabidiol (CBD), cannabigerol (CBG), and cannabinol (CBN).

Cannabis is a Scythian word.^[11][12][13] The ancient Greeks learned of the use of cannabis by observing Scythian funerals, during which cannabis was consumed.^[12] In Akkadian, cannabis was known as qunubu (𐎯𐎫𐎠𐎭𐏂).^[12] The word was adopted in to the Hebrew language as qaneh bosem (קָנֶה בֹּשׂם).^[12]

Cannabis is an annual, dioecious, flowering herb. The leaves are palmately compound or digitate, with serrate leaflets.^[14] The first pair of leaves usually have a single leaflet, the number gradually increasing up to a maximum of about thirteen leaflets per leaf (usually seven or nine), depending on variety and growing conditions. At the top of a flowering plant, this number again diminishes to a single leaflet per leaf. The lower leaf pairs usually occur in an opposite leaf arrangement and the upper leaf pairs in an alternate arrangement on the main stem of a mature plant.

The leaves have a peculiar and diagnostic venation pattern (which varies slightly among varieties) that allows for easy identification of Cannabis leaves from unrelated species with similar leaves. As is common in serrated leaves, each serration has a central vein extending to its tip, but in Cannabis this originates from lower down the central vein of the leaflet, typically opposite to the position of the second notch down. This means that on its way from the midrib of the leaflet to the point of the serration, the vein serving the tip of the serration passes close by the intervening notch. Sometimes the vein will pass tangentially to the notch, but often will pass by at a small distance; when the latter happens a spur vein (or occasionally two) branches off and joins the leaf margin at the deepest point of the notch. Tiny samples of Cannabis also can be identified with precision by microscopic examination of leaf cells and similar features, requiring special equipment and expertise.^[15]

All known strains of Cannabis are wind-pollinated^[16] and the fruit is an achene.^[17] Most strains of Cannabis are short day plants,^[16] with the possible exception of C. sativa subsp. sativa var. spontanea (= C. ruderalis), which is commonly described as "auto-flowering" and may be day-neutral.

Cannabis is predominantly dioecious,^[16][18] having imperfect flowers, with staminate "male" and pistillate "female" flowers occurring on separate plants.^[19] "At a very early period the Chinese recognized the Cannabis plant as dioecious",^[20] and the (c. 3rd century BCE) Erya dictionary defined xi 枲 "male Cannabis" and fu 莩 (or ju 苴) "female Cannabis".^[21] Male flowers are normally borne on loose panicles, and female flowers are borne on racemes.^[22]

Many monoecious varieties have also been described,^[23] in which individual plants bear both male and female flowers.^[24] (Although monoecious plants are often referred to as "hermaphrodites", true hermaphrodites – which are less common in Cannabis – bear staminate and pistillate structures together on individual flowers, whereas monoecious plants bear male and female flowers at different locations on the same plant.) Subdioecy (the occurrence of monoecious individuals and dioecious individuals within the same population) is widespread.^[25][26][27] Many populations have been described as sexually labile.^[28][29][30]

As a result of intensive selection in cultivation, Cannabis exhibits many sexual phenotypes that can be described in terms of the ratio of female to male flowers occurring in the individual, or typical in the cultivar.^[31] Dioecious varieties are preferred for drug production, where the fruits (produced by female flowers) are used. Dioecious varieties are also preferred for textile fiber production, whereas monoecious varieties are preferred for pulp and paper production. It has been suggested that the presence of monoecy can be used to differentiate licit crops of monoecious hemp from illicit drug crops,^[25] but sativa strains often produce monoecious individuals, which is possibly as a result of inbreeding.

Cannabis has been described as having one of the most complicated mechanisms of sex determination among the dioecious plants.^[31] Many models have been proposed to explain sex determination in Cannabis.

Based on studies of sex reversal in hemp, it was first reported by K. Hirata in 1924 that an XY sex-determination system is present.^[29] At the time, the XY system was the only known system of sex determination. The X:A system was first described in Drosophila spp in 1925.^[32] Soon thereafter, Schaffner disputed Hirata's interpretation,^[33] and published results from his own studies of sex reversal in hemp, concluding that an X:A system was in use and that furthermore sex was strongly influenced by environmental conditions.^[30]

Since then, many different types of sex determination systems have been discovered, particularly in plants.^[18] Dioecy is relatively uncommon in the plant kingdom, and a very low percentage of dioecious plant species have been determined to use the XY system. In most cases where the XY system is found it is believed to have evolved recently and independently.^[34]

Since the 1920s, a number of sex determination models have been proposed for Cannabis. Ainsworth describes sex determination in the genus as using "an X/autosome dosage type".^[18]

The question of whether heteromorphic sex chromosomes are indeed present is most conveniently answered if such chromosomes were clearly visible in a karyotype. Cannabis was one of the first plant species to be karyotyped; however, this was in a period when karyotype preparation was primitive by modern standards. Heteromorphic sex chromosomes were reported to occur in staminate individuals of dioecious "Kentucky" hemp, but were not found in pistillate individuals of the same variety. Dioecious "Kentucky" hemp was assumed to use an XY mechanism. Heterosomes were not observed in analyzed individuals of monoecious "Kentucky" hemp, nor in an unidentified German cultivar. These varieties were assumed to have sex chromosome composition XX.^[35] According to other researchers, no modern karyotype of Cannabis had been published as of 1996.^[36] Proponents of the XY system state that Y chromosome is slightly larger than the X, but difficult to differentiate cytologically.^[37]

More recently, Sakamoto and various co-authors^[38][39] have used random amplification of polymorphic DNA (RAPD) to isolate several genetic marker sequences that they name Male-Associated DNA in Cannabis (MADC), and which they interpret as indirect evidence of a male chromosome. Several other research groups have reported identification of male-associated markers using RAPD and amplified fragment length polymorphism.^[40][28][41] Ainsworth commented on these findings, stating,

It is not surprising that male-associated markers are relatively abundant. In dioecious plants where sex chromosomes have not been identified, markers for maleness indicate either the presence of sex chromosomes which have not been distinguished by cytological methods or that the marker is tightly linked to a gene involved in sex determination.^[18]

Environmental sex determination is known to occur in a variety of species.^[42] Many researchers have suggested that sex in Cannabis is determined or strongly influenced by environmental factors.^[30] Ainsworth reviews that treatment with auxin and ethylene have feminizing effects, and that treatment with cytokinins and gibberellins have masculinizing effects.^[18] It has been reported that sex can be reversed in Cannabis using chemical treatment.^[43] A polymerase chain reaction-based method for the detection of female-associated DNA polymorphisms by genotyping has been developed.^[44]

• 
  A male hemp plant
• 
  Dense raceme of female flowers typical of drug-type varieties of Cannabis
• 
  Male Lemon Kush cannabis plant (12 foot plant)
• 
  Male Lemon Kush cannabis Flowers
• 
  A young female Acapulco Gold plant (Mexican x Nepalese). Seed grown plant from seeds obtained from a cannabis seed bank.^[45]
• 
  Acapulco Gold female plant in bloom
• 
  Indoor grown Acapulco Gold female plant in final stages of flowering (flushing in amber and gold tones)

Cannabis plants produce a large number of chemicals as part of their defense against herbivory. One group of these is called cannabinoids, which induce mental and physical effects when consumed.

Cannabinoids, terpenes, terpenoids, and other compounds are secreted by glandular trichomes that occur most abundantly on the floral calyxes and bracts of female plants.^[46]

• 
  Root system side view
• 
  Root system top view
• 
  Micrograph C. sativa (left), C. indica (right)

Cannabis, like many organisms, is diploid, having a chromosome complement of 2n=20, although polyploid individuals have been artificially produced.^[47] The first genome sequence of Cannabis, which is estimated to be 820 Mb in size, was published in 2011 by a team of Canadian scientists.^[48]

The genus Cannabis was formerly placed in the nettle family (Urticaceae) or mulberry family (Moraceae), and later, along with the genus Humulus (hops), in a separate family, the hemp family (Cannabaceae sensu stricto).^[49] Recent phylogenetic studies based on cpDNA restriction site analysis and gene sequencing strongly suggest that the Cannabaceae sensu stricto arose from within the former family Celtidaceae, and that the two families should be merged to form a single monophyletic family, the Cannabaceae sensu lato.^[50][51]

Various types of Cannabis have been described, and variously classified as species, subspecies, or varieties:^[52]

• plants cultivated for fiber and seed production, described as low-intoxicant, non-drug, or fiber types.
• plants cultivated for drug production, described as high-intoxicant or drug types.
• escaped, hybridised, or wild forms of either of the above types.

Cannabis plants produce a unique family of terpeno-phenolic compounds called cannabinoids, some of which produce the "high" which may be experienced from consuming marijuana. There are 483 identifiable chemical constituents known to exist in the cannabis plant,^[53] and at least 85 different cannabinoids have been isolated from the plant.^[54] The two cannabinoids usually produced in greatest abundance are cannabidiol (CBD) and/or Δ⁹-tetrahydrocannabinol (THC), but only THC is psychoactive.^[55] Since the early 1970s, Cannabis plants have been categorized by their chemical phenotype or "chemotype", based on the overall amount of THC produced, and on the ratio of THC to CBD.^[56] Although overall cannabinoid production is influenced by environmental factors, the THC/CBD ratio is genetically determined and remains fixed throughout the life of a plant.^[40] Non-drug plants produce relatively low levels of THC and high levels of CBD, while drug plants produce high levels of THC and low levels of CBD. When plants of these two chemotypes cross-pollinate, the plants in the first filial (F₁) generation have an intermediate chemotype and produce intermediate amounts of CBD and THC. Female plants of this chemotype may produce enough THC to be utilized for drug production.^[56][57]

Whether the drug and non-drug, cultivated and wild types of Cannabis constitute a single, highly variable species, or the genus is polytypic with more than one species, has been a subject of debate for well over two centuries. This is a contentious issue because there is no universally accepted definition of a species.^[58] One widely applied criterion for species recognition is that species are "groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups."^[59] Populations that are physiologically capable of interbreeding, but morphologically or genetically divergent and isolated by geography or ecology, are sometimes considered to be separate species.^[59] Physiological barriers to reproduction are not known to occur within Cannabis, and plants from widely divergent sources are interfertile.^[47] However, physical barriers to gene exchange (such as the Himalayan mountain range) might have enabled Cannabis gene pools to diverge before the onset of human intervention, resulting in speciation.^[60] It remains controversial whether sufficient morphological and genetic divergence occurs within the genus as a result of geographical or ecological isolation to justify recognition of more than one species.^[61][62][63]

The genus Cannabis was first classified using the "modern" system of taxonomic nomenclature by Carl Linnaeus in 1753, who devised the system still in use for the naming of species.^[64] He considered the genus to be monotypic, having just a single species that he named Cannabis sativa L.^{[a 1]} Linnaeus was familiar with European hemp, which was widely cultivated at the time. This classification was supported by Christiaan Hendrik Persoon (in 1807), Lindley (in 1838) and De Candollee (in 1867). These first classification attempts resulted in a four group division:^[65]

• Kif (southern hemp - psychoactive)
• Vulgaris (intermediate - psychoactive and fiber)
• Pedemontana (northern hemp - fiber)
• Chinensis (northern hemp - fiber)

In 1785, evolutionary biologist Jean-Baptiste de Lamarck published a description of a second species of Cannabis, which he named Cannabis indica Lam.^[66] Lamarck based his description of the newly named species on morphological aspects (trichomes, leaf shape) and geographic localization of plant specimens collected in India. He described C. indica as having poorer fiber quality than C. sativa, but greater utility as an inebriant. Also, C. indica was considered smaller, by Lamarck. Also, woodier stems, alternate ramifications of the branches, narrow leaflets, and a villous calyx in the female flowers were characteristics noted by the botanist.^[65]

In 1843, William O’Shaughnessy, used "Indian hemp (C. indica)" in a work title. The author claimed that this choice wasn't based on a clear distinction between C. sativa and C. indica, but may have been influenced by the choice to use the term "Indian hemp" (linked to the plant's history in India), hence naming the species as indica.^[65]

Additional Cannabis species were proposed in the 19th century, including strains from China and Vietnam (Indo-China) assigned the names Cannabis chinensis Delile, and Cannabis gigantea Delile ex Vilmorin.^[67] However, many taxonomists found these putative species difficult to distinguish. In the early 20th century, the single-species concept (monotypic classification) was still widely accepted, except in the Soviet Union, where Cannabis continued to be the subject of active taxonomic study. The name Cannabis indica was listed in various Pharmacopoeias, and was widely used to designate Cannabis suitable for the manufacture of medicinal preparations.^[68]

In 1924, Russian botanist D.E. Janichevsky concluded that ruderal Cannabis in central Russia is either a variety of C. sativa or a separate species, and proposed C. sativa L. var. ruderalis Janisch, and Cannabis ruderalis Janisch, as alternative names.^[52] In 1929, renowned plant explorer Nikolai Vavilov assigned wild or feral populations of Cannabis in Afghanistan to C. indica Lam. var. kafiristanica Vav., and ruderal populations in Europe to C. sativa L. var. spontanea Vav.^[57][67] Vavilov, in 1931, proposed a three species system, independently reinforced by Schultes et al (1975)^[69] and Emboden (1974):^[70] C. sativa, C. indica and C. ruderalis.^[65]

In 1940, Russian botanists Serebriakova and Sizov proposed a complex poly-species classification in which they also recognized C. sativa and C. indica as separate species. Within C. sativa they recognized two subspecies: C. sativa L. subsp. culta Serebr. (consisting of cultivated plants), and C. sativa L. subsp. spontanea (Vav.) Serebr. (consisting of wild or feral plants). Serebriakova and Sizov split the two C. sativa subspecies into 13 varieties, including four distinct groups within subspecies culta. However, they did not divide C. indica into subspecies or varieties.^[52][71][72] Zhukovski, in 1950, also proposed a two-species system, but with C. sativa L. and C. ruderalis.^[73]

In the 1970s, the taxonomic classification of Cannabis took on added significance in North America. Laws prohibiting Cannabis in the United States and Canada specifically named products of C. sativa as prohibited materials. Enterprising attorneys for the defense in a few drug busts argued that the seized Cannabis material may not have been C. sativa, and was therefore not prohibited by law. Attorneys on both sides recruited botanists to provide expert testimony. Among those testifying for the prosecution was Dr. Ernest Small, while Dr. Richard E. Schultes and others testified for the defense. The botanists engaged in heated debate (outside of court), and both camps impugned the other's integrity.^[61][62] The defense attorneys were not often successful in winning their case, because the intent of the law was clear.^[74]

In 1976, Canadian botanist Ernest Small^[75] and American taxonomist Arthur Cronquist published a taxonomic revision that recognizes a single species of Cannabis with two subspecies (hemp or drug; based on THC and CBD levels) and two varieties in each (domesticated or wild). The framework is thus:

• C. sativa L. subsp. sativa, presumably selected for traits that enhance fiber or seed production.
  • C. sativa L. subsp. sativa var. sativa, domesticated variety.
  • C. sativa L. subsp. sativa var. spontanea Vav., wild or escaped variety.
• C. sativa L. subsp. indica (Lam.) Small & Cronq.,^[67] primarily selected for drug production.
  • C. sativa L. subsp. indica var. indica, domesticated variety.
  • C. sativa subsp. indica var. kafiristanica (Vav.) Small & Cronq, wild or escaped variety.

This classification was based on several factors including interfertility, chromosome uniformity, chemotype, and numerical analysis of phenotypic characters.^[56][67][76]

Professors William Emboden, Loran Anderson, and Harvard botanist Richard E. Schultes and coworkers also conducted taxonomic studies of Cannabis in the 1970s, and concluded that stable morphological differences exist that support recognition of at least three species, C. sativa, C. indica, and C. ruderalis.^{[77][78][79][80]} For Schultes, this was a reversal of his previous interpretation that Cannabis is monotypic, with only a single species.^[81] According to Schultes' and Anderson's descriptions, C. sativa is tall and laxly branched with relatively narrow leaflets, C. indica is shorter, conical in shape, and has relatively wide leaflets, and C. ruderalis is short, branchless, and grows wild in Central Asia. This taxonomic interpretation was embraced by Cannabis aficionados who commonly distinguish narrow-leafed "sativa" strains from wide-leafed "indica" strains.^[82] McPartland's review finds the Schultes taxonomy inconsistent with prior work (protologs) and partly responsible for the popular usage.^[83]

Molecular analytical techniques developed in the late 20th century are being applied to questions of taxonomic classification. This has resulted in many reclassifications based on evolutionary systematics. Several studies of random amplified polymorphic DNA (RAPD) and other types of genetic markers have been conducted on drug and fiber strains of Cannabis, primarily for plant breeding and forensic purposes.^{[84][85][28][86][87]} Dutch Cannabis researcher E.P.M. de Meijer and coworkers described some of their RAPD studies as showing an "extremely high" degree of genetic polymorphism between and within populations, suggesting a high degree of potential variation for selection, even in heavily selected hemp cultivars.^[40] They also commented that these analyses confirm the continuity of the Cannabis gene pool throughout the studied accessions, and provide further confirmation that the genus consists of a single species, although theirs was not a systematic study per se.

An investigation of genetic, morphological, and chemotaxonomic variation among 157 Cannabis accessions of known geographic origin, including fiber, drug, and feral populations showed cannabinoid variation in Cannabis germplasm. The patterns of cannabinoid variation support recognition of C. sativa and C. indica as separate species, but not C. ruderalis. C. sativa contains fiber and seed landraces, and feral populations, derived from Europe, Central Asia, and Turkey. Narrow-leaflet and wide-leaflet drug accessions, southern and eastern Asian hemp accessions, and feral Himalayan populations were assigned to C. indica.^[57] In 2005, a genetic analysis of the same set of accessions led to a three-species classification, recognizing C. sativa, C. indica, and (tentatively) C. ruderalis.^[60] Another paper in the series on chemotaxonomic variation in the terpenoid content of the essential oil of Cannabis revealed that several wide-leaflet drug strains in the collection had relatively high levels of certain sesquiterpene alcohols, including guaiol and isomers of eudesmol, that set them apart from the other putative taxa.^[88]

A 2020 analysis of single-nucleotide polymorphisms reports five clusters of cannabis, roughly corresponding to hemps (including folk "Ruderalis") folk "Indica" and folk "Sativa".^[89]

Despite advanced analytical techniques, much of the cannabis used recreationally is inaccurately classified. One laboratory at the University of British Columbia found that Jamaican Lamb's Bread, claimed to be 100% sativa, was in fact almost 100% indica (the opposite strain).^[90] Legalization of cannabis in Canada (as of 17 October 2018^[update]) may help spur private-sector research, especially in terms of diversification of strains. It should also improve classification accuracy for cannabis used recreationally. Legalization coupled with Canadian government (Health Canada) oversight of production and labelling will likely result in more—and more accurate—testing to determine exact strains and content. Furthermore, the rise of craft cannabis growers in Canada should ensure quality, experimentation/research, and diversification of strains among private-sector producers.^[91]

The scientific debate regarding taxonomy has had little effect on the terminology in widespread use among cultivators and users of drug-type Cannabis. Cannabis aficionados recognize three distinct types based on such factors as morphology, native range, aroma, and subjective psychoactive characteristics. "Sativa" is the most widespread variety, which is usually tall, laxly branched, and found in warm lowland regions. "Indica" designates shorter, bushier plants adapted to cooler climates and highland environments. "Ruderalis" is the informal name for the short plants that grow wild in Europe and Central Asia.^[83]

Mapping the morphological concepts to scientific names in the Small 1976 framework, "Sativa" generally refers to C. sativa subsp. indica var. indica, "Indica" generally refers to C. sativa subsp. i. kafiristanica (also known as afghanica), and "Ruderalis", being lower in THC, is the one that can fall into C. sativa subsp. sativa. The three names fit in Schultes's framework better, if one overlooks its inconsistencies with prior work.^[83] Definitions of the three terms using factors other than morphology produces different, often conflicting results.

Breeders, seed companies, and cultivators of drug type Cannabis often describe the ancestry or gross phenotypic characteristics of cultivars by categorizing them as "pure indica", "mostly indica", "indica/sativa", "mostly sativa", or "pure sativa". These categories are highly arbitrary, however: one "AK-47" hybrid strain has received both "Best Sativa" and "Best Indica" awards.^[83]

Cannabis likely split from its closest relative, Humulus (hops), during the mid Oligocene, around 27.8 million years ago according to molecular clock estimates. The centre of origin of Cannabis is likely in the northeastern Tibetan Plateau. The pollen of Humulus and Cannabis are very similar and difficult to distinguish. The oldest pollen thought to be from Cannabis is from Ningxia, China, on the boundary between the Tibetan Plateau and the Loess Plateau, dating to the early Miocene, around 19.6 million years ago. Cannabis was widely distributed over Asia by the Late Pleistocene. The oldest known Cannabis in South Asia dates to around 32,000 years ago.^[92]

Cannabis is used for a wide variety of purposes.

According to genetic and archaeological evidence, cannabis was first domesticated about 12,000 years ago in East Asia during the early Neolithic period.^[5] The use of cannabis as a mind-altering drug has been documented by archaeological finds in prehistoric societies in Eurasia and Africa.^[93] The oldest written record of cannabis usage is the Greek historian Herodotus's reference to the central Eurasian Scythians taking cannabis steam baths.^[94] His (c. 440 BCE) Histories records, "The Scythians, as I said, take some of this hemp-seed [presumably, flowers], and, creeping under the felt coverings, throw it upon the red-hot stones; immediately it smokes, and gives out such a vapour as no Greek vapour-bath can exceed; the Scyths, delighted, shout for joy."^[95] Classical Greeks and Romans also used cannabis.

In China, the psychoactive properties of cannabis are described in the Shennong Bencaojing (3rd century AD).^[96] Cannabis smoke was inhaled by Daoists, who burned it in incense burners.^[96]

In the Middle East, use spread throughout the Islamic empire to North Africa. In 1545, cannabis spread to the western hemisphere where Spaniards imported it to Chile for its use as fiber. In North America, cannabis, in the form of hemp, was grown for use in rope, cloth and paper.^{[97][98][99][100]}

Cannabinol (CBN) was the first compound to be isolated from cannabis extract in the late 1800s. Its structure and chemical synthesis were achieved by 1940, followed by some of the first preclinical research studies to determine the effects of individual cannabis-derived compounds in vivo.^[101]

Globally, in 2013, 60,400 kilograms of cannabis were produced legally.^[102]

Cannabis is a popular recreational drug around the world, only behind alcohol, caffeine, and tobacco. In the U.S. alone, it is believed that over 100 million Americans have tried cannabis, with 25 million Americans having used it within the past year.^[when?][104] As a drug it usually comes in the form of dried marijuana, hashish, or various extracts collectively known as hashish oil.^[10]

Normal cognition is restored after approximately three hours for larger doses via a smoking pipe, bong or vaporizer.^[105] However, if a large amount is taken orally the effects may last much longer. After 24 hours to a few days, minuscule psychoactive effects may be felt, depending on dosage, frequency and tolerance to the drug.

Cannabidiol (CBD), which has no intoxicating effects by itself^[55] (although sometimes showing a small stimulant effect, similar to caffeine),^[106] is thought to attenuate (i.e., reduce)^[107] the anxiety-inducing effects of high doses of THC, particularly if administered orally prior to THC exposure.^[108]

According to Delphic analysis by British researchers in 2007, cannabis has a lower risk factor for dependence compared to both nicotine and alcohol.^[109] However, everyday use of cannabis may be correlated with psychological withdrawal symptoms, such as irritability or insomnia,^[105] and susceptibility to a panic attack may increase as levels of THC metabolites rise.^[110][111] Cannabis withdrawal symptoms are typically mild and are not life-threatening.^[112] Risk of adverse outcomes from cannabis use may be reduced by implementation of evidence-based education and intervention tools communicated to the public with practical regulation measures.^[113]

In 2014 there were an estimated 182.5 million cannabis users worldwide (3.8% of the global population aged 15–64).^[114] This percentage did not change significantly between 1998 and 2014.^[114]

Medical cannabis (or medical marijuana) refers to the use of cannabis and its constituent cannabinoids, in an effort to treat disease or improve symptoms. Cannabis is used to reduce nausea and vomiting during chemotherapy, to improve appetite in people with HIV/AIDS, and to treat chronic pain and muscle spasms.^[115][116] Cannabinoids are under preliminary research for their potential to affect stroke.^[117] Evidence is lacking for depression, anxiety, attention deficit hyperactivity disorder, Tourette syndrome, post-traumatic stress disorder, and psychosis.^[118] Two extracts of cannabis – dronabinol and nabilone – are approved by the FDA as medications in pill form for treating the side effects of chemotherapy and AIDS.^[119]

Short-term use increases both minor and major adverse effects.^[116] Common side effects include dizziness, feeling tired, vomiting, and hallucinations.^[116] Long-term effects of cannabis are not clear.^[120] Concerns including memory and cognition problems, risk of addiction, schizophrenia in young people, and the risk of children taking it by accident.^[115]

The term hemp is used to name the durable soft fiber from the Cannabis plant stem (stalk). Cannabis sativa cultivars are used for fibers due to their long stems; Sativa varieties may grow more than six metres tall. However, hemp can refer to any industrial or foodstuff product that is not intended for use as a drug. Many countries regulate limits for psychoactive compound (THC) concentrations in products labeled as hemp.

Cannabis for industrial uses is valuable in tens of thousands of commercial products, especially as fibre^[121] ranging from paper, cordage, construction material and textiles in general, to clothing. Hemp is stronger and longer-lasting than cotton. It also is a useful source of foodstuffs (hemp milk, hemp seed, hemp oil) and biofuels. Hemp has been used by many civilizations, from China to Europe (and later North America) during the last 12,000 years.^[121][122] In modern times novel applications and improvements have been explored with modest commercial success.^[123][124]

In the US, "industrial hemp" is classified by the federal government as cannabis containing no more than 0.3% THC by dry weight. This classification was established in the 2018 Farm Bill and was refined to include hemp-sourced extracts, cannabinoids, and derivatives in the definition of hemp.^[125]

The Cannabis plant has a history of medicinal use dating back thousands of years across many cultures.^[126] The Yanghai Tombs, a vast ancient cemetery (54 000 m²) situated in the Turfan district of the Xinjiang Uyghur Autonomous Region in northwest China, have revealed the 2700-year-old grave of a shaman. He is thought to have belonged to the Jushi culture recorded in the area centuries later in the Hanshu, Chap 96B.^[127] Near the head and foot of the shaman was a large leather basket and wooden bowl filled with 789g of cannabis, superbly preserved by climatic and burial conditions. An international team demonstrated that this material contained THC. The cannabis was presumably employed by this culture as a medicinal or psychoactive agent, or an aid to divination. This is the oldest documentation of cannabis as a pharmacologically active agent.^[128] The earliest evidence of cannabis smoking has been found in the 2,500-year-old tombs of Jirzankal Cemetery in the Pamir Mountains in Western China, where cannabis residue were found in burners with charred pebbles possibly used during funeral rituals.^[129][130]

Settlements which date from c. 2200–1700 BCE in the Bactria and Margiana contained elaborate ritual structures with rooms containing everything needed for making drinks containing extracts from poppy (opium), hemp (cannabis), and ephedra (which contains ephedrine).^{[131]: 262 } Although there is no evidence of ephedra being used by steppe tribes, they engaged in cultic use of hemp. Cultic use ranged from Romania to the Yenisei River and had begun by 3rd millennium BC Smoking hemp has been found at Pazyryk.^{[131]: 306 }

Cannabis is first referred to in Hindu Vedas between 2000 and 1400 BCE, in the Atharvaveda. By the 10th century CE, it has been suggested that it was referred to by some in India as "food of the gods".^[132] Cannabis use eventually became a ritual part of the Hindu festival of Holi. One of the earliest to use this plant in medical purposes was Korakkar, one of the 18 Siddhas.^{[133][134][self-published source?]} The plant is called Korakkar Mooli in the Tamil language, meaning Korakkar's herb.^[135][136]

In Buddhism, cannabis is generally regarded as an intoxicant and may be a hindrance to development of meditation and clear awareness. In ancient Germanic culture, Cannabis was associated with the Norse love goddess, Freya.^[137][138] An anointing oil mentioned in Exodus is, by some translators, said to contain Cannabis.^[139]

In modern times, the Rastafari movement has embraced Cannabis as a sacrament.^[140] Elders of the Ethiopian Zion Coptic Church, a religious movement founded in the U.S. in 1975 with no ties to either Ethiopia or the Coptic Church, consider Cannabis to be the Eucharist, claiming it as an oral tradition from Ethiopia dating back to the time of Christ.^[141] Like the Rastafari, some modern Gnostic Christian sects have asserted that Cannabis is the Tree of Life.^[142][143] Other organized religions founded in the 20th century that treat Cannabis as a sacrament are the THC Ministry,^[144] Cantheism,^[145] the Cannabis Assembly^[146] and the Church of Cognizance.

Since the 13th century CE, cannabis has been used among Sufis^[147][148] – the mystical interpretation of Islam that exerts strong influence over local Muslim practices in Bangladesh, India, Indonesia, Turkey, and Pakistan. Cannabis preparations are frequently used at Sufi festivals in those countries.^[147] Pakistan's Shrine of Lal Shahbaz Qalandar in Sindh province is particularly renowned for the widespread use of cannabis at the shrine's celebrations, especially its annual Urs festival and Thursday evening dhamaal sessions – or meditative dancing sessions.^[149][150]

• All pages with titles beginning with Cannabis
• All pages with titles containing Cannabis
• Cannabis drug testing
• Cannabis edible
• Cannabis flower essential oil
• Hash, Marihuana & Hemp Museum
• Indian Hemp Drugs Commission
• Legal history of cannabis in the United States
• Legality of cannabis by U.S. jurisdiction
• List of books about cannabis
• List of celebrities who own cannabis businesses
• Occupational health concerns of cannabis use

• International Plant Names Index (IPNI)