Flowering Cannabis plant
|Source plant(s)||Cannabis sativa, Cannabis indica, Cannabis ruderalis|
|Part(s) of plant||flower|
|Geographic origin||Central and South Asia.|
|Active ingredients||Tetrahydrocannabinol, Cannabidiol, Cannabinol, Tetrahydrocannabivarin|
|Main producers||Afghanistan (primary), China, Netherlands, United States, Pakistan, India, Thailand, Turkey, Laos, Burma, Mexico, Colombia, Jamaica|
Cannabis, also known as marijuana (from the Mexican Spanish marihuana), and by other names,a[›] is a preparation of the Cannabis plant intended for use as a psychoactive drug and as medicine. Pharmacologically, the principal psychoactive constituent of cannabis is tetrahydrocannabinol (THC); it is one of 483 known compounds in the plant, including at least 84 other cannabinoids, such as cannabidiol (CBD), cannabinol (CBN), tetrahydrocannabivarin (THCV). and cannabigerol (CBG).
Contemporary uses of cannabis are as a recreational or medicinal drug, and as part of religious or spiritual rites; the earliest recorded uses date from the 3rd millennium BC. In 2004, the United Nations estimated that global consumption of cannabis indicated that approximately 4% of the adult world population (162 million people) used cannabis annually, and that approximately 0.6% (22.5 million) of people used cannabis daily. In the United States, cannabis is the most commonly used illicit drug (under federal law); 5.1% of Americans said they used marijuana in the past 30 days. In 1977, 38% of 12th graders reported using cannabis in the past month; in 2011, 23% of the same age group reported using cannabis in the same time span. Since the early 20th century cannabis has been subject to legal restrictions with the possession, use, and sale of cannabis preparations containing psychoactive cannabinoids currently illegal in most countries of the world; the United Nations has said that cannabis is the most-used illicit drug in the world.
Cannabis has psychoactive and physiological effects when consumed. Some alternative media sources report that minimum amount of THC required to have a perceptible psychoactive effect is about 10 micrograms per kilogram of body weight.[medical citation needed] Aside from a subjective change in perception and, most notably, mood, the most common short-term physical and neurological effects include increased heart rate, increased appetite and consumption of food[medical citation needed], lowered blood pressure, impairment of short-term and working memory, psychomotor coordination, and concentration. Long-term effects are less clear. In humans, relatively few adverse clinical health effects have been documented from chronic cannabis use.[medical citation needed]
While many psychoactive drugs clearly fall into the category of either stimulant, depressant, or hallucinogen, cannabis exhibits a mix of all properties, perhaps leaning the most towards hallucinogenic or psychedelic properties, though with other effects quite pronounced as well. THC is typically considered the primary active component of the cannabis plant; various scientific studies have suggested that certain other cannabinoids like CBD may also play a significant role in its psychoactive effects.
Cannabis used medically has several well-documented beneficial effects. Among these are: the amelioration of nausea and vomiting, stimulation of hunger in chemotherapy and AIDS patients, lowered intraocular eye pressure (shown to be effective for treating glaucoma), as well as general analgesic effects (pain reliever).b[›]
Less confirmed individual studies also have been conducted indicating cannabis to be beneficial to a gamut of conditions running from multiple sclerosis to depression. Synthesized cannabinoids are also sold as prescription drugs, including Marinol (dronabinol in the United States and Germany) and Cesamet (nabilone in Canada, Mexico, the United States and the United Kingdom).b[›]
Currently, the U.S. Food and Drug Administration (FDA) has not approved smoked cannabis for any condition or disease in the United States, largely because the FDA claims good quality scientific evidence for its use from U.S. studies is lacking. Eighteen states and the District of Colombia have legalized cannabis for medical use. The United States Supreme Court has ruled in United States v. Oakland Cannabis Buyers' Coop and Gonzales v. Raich that it is the federal government that has the right to regulate and criminalize cannabis, even for medical purposes. Canada, Spain, The Netherlands and Austria have legalized some form of cannabis for medicinal use.
Though the long-term effects of cannabis have been studied, there remains much to be concluded. Many studies have investigated whether long-term use of cannabis can cause or contribute to the development of illnesses such as heart disease, bipolar disorder, depression, mood swings or schizophrenia. Its effects on intelligence, memory, respiratory functions and the possible relationship of cannabis use to mental disorders such as schizophrenia, psychosis, depersonalization disorder and depression are still under discussion.
Both advocates and opponents of cannabis are able to call upon numerous scientific studies supporting their respective positions. For instance, while cannabis has been implicated in the development of various mental disorders in some studies, these studies differ widely as to whether cannabis use is the cause of the mental problems displayed in heavy users, whether the mental problems are exacerbated by cannabis use, or whether both the cannabis use and the mental problems are the effects of some other cause.
It has been pointed out that as cannabis use has risen, rates of schizophrenia have not risen in tandem. Lester Grinspoon argues that the cannabis-causes-psychosis argument is disproved by the lack of "even a blip in the incidence of schizophrenia in the US after millions of people started smoking marijuana in the 1960s". Worldwide prevalence of schizophrenia is about 1% in adults; the amount of cannabis use in any given country seems to have no effect on that rate.
A medical study published in 2009 taken by the Medical Research Council in London, showed there was no significant effect of THC on [11C]-raclopride binding. Thus concluding, recreational cannabis users do not release significant amounts of dopamine from an oral THC dose equivalent to a standard cannabis cigarette, leading to vulnerability to psychosis or schizophrenia.
Positive effects of the drug have also been observed. For example, in a recent study researchers found that compared with those who did not smoke cannabis, long-term cannabis smokers were roughly 62% less likely to develop head and neck cancers.
Dr. Jack E. Henningfield of NIDA ranked the relative addictiveness of 6 substances (cannabis, caffeine, cocaine, alcohol, heroin and nicotine). Cannabis ranked least addictive, with caffeine the second least addictive and nicotine the most addictive.
Adolescent brain development
A 35-year cohort study published August 2012 in Proceedings of the National Academy of Sciences and funded partly by NIDA and other NIH institutes reported an association between long-term cannabis use and neuropsychological decline, even after controlling for education. It was found that the persistent, dependent use of marijuana before age 18 was associated with lasting harm to a person's intelligence, attention and memory, and were suggestive of neurological harm from cannabis. Quitting cannabis did not appear to reverse the loss. However, individuals who started cannabis use after the age of 18 did not show similar declines.
Results of the study came into question when in a new analysis, published January 2013 in Proceedings of the National Academy of Sciences, researchers from Oslo's Ragnar Frisch Center for Economic Research noted other differences among the study group including education, occupation and other socioeconomic factors that showed the same effect on IQ as cannabis use. From the abstract: "existing research suggests an alternative confounding model based on time-varying effects of socioeconomic status on IQ. A simulation of the confounding model reproduces the reported associations from the [August 2012 study], suggesting that the causal effects estimated in Meier et al. are likely to be overestimates, and that the true effect could be zero". The researchers pointed to three other studies which showed cannabis did not cause a decline in IQ. The studies showed that heavy smokers had clear reductions in IQ, but they were not permanent.
A 2012 study conducted by researchers at UC San Diego failed to show deleterious effects on the adolescent brain from cannabis use. Researchers looked at brain scans taken before-and-after of subjects aged 16–20 years who consumed alcohol and compared them to subjects of the same age who used cannabis instead. The 92 person study was conducted over an eighteen-month period. While teen alcohol use resulted in observable reduced white matter brain tissue health, cannabis use was not linked to any structural damage. The study did not measure the subjects' cognitive performance. Publication is scheduled for April 2013 in Alcoholism: Clinical and Experimental Research.
Gateway drug theory
Since the 1950s, United States drug policies have been guided by the assumption that trying cannabis increases the probability that users will eventually use "harder" drugs. This hypothesis has been one of the central pillars of anti-cannabis drug policy in the United States, though the validity and implications of this hypothesis are hotly debated. Studies have shown that tobacco smoking is a better predictor of concurrent illicit hard drug use than smoking cannabis.
No widely accepted study has ever demonstrated a cause-and-effect relationship between the use of cannabis and the later use of harder drugs like heroin and cocaine. However, the prevalence of tobacco cigarette advertising and the practice of mixing tobacco and cannabis together in a single large joint, common in Europe, are believed to be cofactors in promoting nicotine dependency among young people trying cannabis.
A 2005 comprehensive review of the literature on the cannabis gateway hypothesis found that pre-existing traits may predispose users to addiction in general, the availability of multiple drugs in a given setting confounds predictive patterns in their usage, and drug sub-cultures are more influential than cannabis itself. The study called for further research on "social context, individual characteristics, and drug effects" to discover the actual relationships between cannabis and the use of other drugs.
Some studies state that while there is no proof for this gateway hypothesis, young cannabis users should still be considered as a risk group for intervention programs. 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.
Another gateway hypothesis is that a gateway effect may be detected as a result of the "common factors" involved with using any illegal drug. Because of its illegal status, cannabis users are more likely to be in situations which allow them to become acquainted with people who use and sell other illegal drugs. By this argument, some studies have shown that alcohol and tobacco may be regarded as gateway drugs. However, a more parsimonious explanation could be that cannabis is simply more readily available (and at an earlier age) than illegal hard drugs, and alcohol/tobacco are in turn easier to obtain earlier than cannabis (though the reverse may be true in some areas), thus leading to the "gateway sequence" in those people who are most likely to experiment with any drug offered.
A 2010 study published in the Journal of Health and Social Behavior found that the main factors in users moving on to other drugs were age, wealth, unemployment status, and psychological stress. The study concluded that there is no validity to the "gateway theory" and that drug use is more closely tied to a person's life situation, although cannabis users are more likely to use other drugs.
Memory, learning, and intelligence
Researchers from the University of California, San Diego School of Medicine failed to show substantial, systemic neurological effects from long-term recreational use of cannabis. Their findings were published in the July 2003 issue of the Journal of the International Neuropsychological Society. The research team, headed by Dr Igor Grant, found that cannabis use did affect perception, but did not cause permanent brain damage. Researchers looked at data from 15 previously published controlled studies involving 704 long-term cannabis users and 484 nonusers. The results showed long-term cannabis use was only marginally harmful on the memory and learning. Other functions such as reaction time, attention, language, reasoning ability, perceptual and motor skills were unaffected. The observed effects on memory and learning, they said, showed long-term cannabis use caused "selective memory defects", but that the impact was "of a very small magnitude".
According to a 2011 study published in the American Journal of Epidemiology, obesity is lower in cannabis users than in nonusers. Authors of the study looked at data from two representative epidemiological studies for US citizens aged 18 and over. Obesity rates in those who didn't use cannabis were 22% and 25.3%. Study participants who smoked cannabis at least three times a week had obesity rates of 14.3% and 17.2%. The association between cannabis smoking and lower risk of obesity remained strong after factors such as cigarette smoking, age and gender, which could have an impact on obesity, were taken into account.
Cannabis is known for inducing hunger, but two cannabinoids, THCV and cannabidiol, were found to have an appetite suppressing effect. In animal tests, the drug also had an impact on the level of fat in the body as well as its response to insulin. Cannabis compounds were shown to raise metabolism in rats, leading to lower levels of fat in the liver and lower cholesterol. Human trials are being conducted to find a drug targeting obesity-related diseases.
A 2012 study published in JAMA and funded by National Institutes of Health looked at a population of over 5,115 American men and women to see whether smoked cannabis has effects on the pulmonary system similar to those from smoking tobacco. The researchers found "Occasional and low cumulative marijuana use was not associated with adverse effects on pulmonary function." Smoking an average of one joint a day for seven years, they found, did not worsen pulmonary health.
Dr. Donald Tashkin commented on the study, saying it confirmed findings from several other studies showing "that essentially there is no significant relationship between marijuana exposure and impairment in lung function." He noted despite containing similar noxious ingredients, one reason cannabis smoke may not be as harmful as tobacco smoke may be due to the anti-inflammatory effects of THC. "We don't know for sure but a very reasonable possibility is that THC may actually interfere with the development of chronic obstructive pulmonary disease", Tashkin elaborated. In his own research, Tashkin unexpectedly found that smoking up to three joints a day appeared to have no decrease in lung function. Tashkin said, "I think that the bottom line is that there does not appear to be any negative impact on lung function of marijuana smoking."
Due to the low number of studies conducted on cannabis, there is not enough evidence to reach a conclusion reagrding the effect of cannabis on overall risk of death or lifespan. Cannabis has not been proven to have caused deaths but an association is currently being researched." There are medical reports of occasional infarction, stroke and other cardiovascular side effects. Marijuana's cardiovascular effects are not associated with serious health problems for most young, healthy users.
According to a 2006 United Kingdom government report, using cannabis is much less dangerous than tobacco, prescription drugs, and alcohol in social harms, physical harm, and addiction. Harvard's Dr. Lester Grinspoon, has stated in a newspaper editorial that "herbal marijuana is remarkably nontoxic".
Dr. Stephen Ross, a professor of child psychiatry and addiction at New York University's Tish Hospital explains reports of some cannabis-related deaths: "deaths associated with the drug are the result of activities undertaken while on the drug, such as driving under the influence". The US Substance Abuse and Mental Health Services Administration stated in its July 2001 report from the Drug Abuse Warning Network Mortality Data: "Marijuana is rarely the only drug involved in a drug abuse death. Thus, in most cases, the proportion of marijuana-involved cases labeled as 'One drug' (i.e., marijuana only) will be zero or nearly zero".
THC, the principal psychoactive constituent of the cannabis plant, has an extremely low toxicity. A 1998 study published in The Lancet reports: "There are no confirmed published cases worldwide of human deaths from cannabis poisoning, and the dose of THC required to produce 50% mortality in rodents is extremely high compared with other commonly used drugs". Cannabis researcher Dr. Paul Hornby said that "you have to smoke something like 15,000 joints in 20 minutes to get a toxic amount of delta-9 tetrahydrocannibinol". Recorded fatalities resulting from cannabis overdose in animals are generally only after intravenous injection of hashish oil.
Many studies have looked at the effects of smoking cannabis on the respiratory system. Cannabis smoke contains thousands of organic and inorganic chemical compounds. This tar is chemically similar to that found in tobacco smoke or cigars. Over fifty known carcinogens have been identified in cannabis smoke. These include nitrosamines, reactive aldehydes, and polycylic hydrocarbons, including benz[a]pyrene. Marijuana smoke was listed as a cancer agent in California in 2009. A 2012 literature review by the British Lung Foundation identified cannabis smoke as a carcinogen and also found awareness of the danger was low compared with the high awareness of the dangers of smoking tobacco particularly among younger users. Other observations include increased risk from each marijuana cigarette due to drawing in large puffs of smoke and holding them; lack of research on the effect of cannabis smoke alone due to common mixing of cannabis and tobacco and frequent tobacco use by cannabis users; low rate of addiction compared to tobacco; and episodic nature of cannabis use compared to steady frequent smoking of tobacco. The review has been criticized by David Nutt. In contrast to the British Lung Foundation report, a large 2006 study found no lung cancer link to marijuana, even in heavy smokers, when adjusting for several confounders including cigarette smoking and alcohol use.
Constraints on open research
Cannabis research is challenging since the plant is illegal in most countries. Research-grade samples of the drug are difficult to obtain for research purposes, unless granted under authority of national governments.
This issue was highlighted in the United States by the clash between Multidisciplinary Association for Psychedelic Studies (MAPS), an independent research group, and the National Institute on Drug Abuse (NIDA), a federal agency charged with the application of science to the study of drug abuse. The NIDA largely operates under the general control of the Office of National Drug Control Policy (ONDCP), a White House office responsible for the direct coordination of all legal, legislative, scientific, social and political aspects of federal drug control policy.
The cannabis that is available for research studies in the United States is grown at the University of Mississippi and solely controlled by the NIDA, which has veto power over the Food and Drug Administration (FDA) to define accepted protocols. Since 1942, when cannabis was removed from the U.S. Pharmacopoeia and its medical use was prohibited, there have been no legal (under federal law) privately funded cannabis production projects. This has resulted in a limited amount of research being done and possibly in NIDA producing cannabis which has been alleged to be of very low potency and inferior quality.
MAPS, in conjunction with Professor Lyle Craker, PhD, the director of the Medicinal Plant Program at the University of Massachusetts Amherst, sought to provide independently grown cannabis of more appropriate research quality for FDA-approved research studies, and encountered opposition by NIDA, the ONDCP, and the U.S. Drug Enforcement Administration (DEA).
In countries such as the United Kingdom a license for growing cannabis is required if it is to be used for botanical or scientific reasons. It is referred to as a "controlled drug". In such countries a greater depth and variety of scientific research has been performed. Recently several habitual smokers were invited to partake in various tests by British medical companies in order for the UK government to ascertain the influence of cannabis on operating a motor vehicle, with the conclusion that marijuana strongly impairs the ability to drive a motor vehicle.
Varieties and strains
Cannabis indica may have a CBD:THC ratio 4–5 times that of Cannabis sativa. Cannabis strains with relatively high CBD:THC ratios are less likely to induce anxiety than vice versa. This may be due to CBD's antagonistic effects at the cannabinoid receptors, compared to THC's partial agonist effect. CBD is also a 5-HT1A receptor agonist, which may also contribute to an anxiolytic effect. This likely means the high concentrations of CBD found in Cannabis indica mitigate the anxiogenic effect of THC significantly. The effects of sativa are well known for its cerebral high, hence used daytime as medical cannabis, while indica are well known for its sedative effects and preferred night time as medical cannabis.
Concentration of psychoactive ingredients
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." The three main forms of cannabis products are the flower, 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."
A scientific study published in 2000 in the Journal of Forensic Sciences (JFS) found that the potency (THC content) of confiscated cannabis in the United States (US) rose from "approximately 3.3% in 1983 and 1984", to "4.47% in 1997". It also concluded that "other major cannabinoids (i.e., CBD, CBN, and CBC)" (other chemicals in cannabis) "showed no significant change in their concentration over the years". More recent research undertaken at the University of Mississippi's Potency Monitoring Project has found that average THC levels in cannabis samples between 1975 and 2007 have increased from 4% in 1983 to 9.6% in 2007.
Australia's National Cannabis Prevention and Information Centre (NCPIC) states that the buds (flowers) of the female cannabis plant contain the highest concentration of THC, followed by the leaves. The stalks and seeds have "much lower THC levels". The UN states that the leaves can contain ten times less THC than the buds, and the stalks one hundred times less THC.
After revisions to cannabis rescheduling 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 (despite the fact that skunk can sometimes be incorrectly mistaken for all types of herbal cannabis). Extracts such as hashish and hash oil typically contain more THC than high potency cannabis flowers.
While commentators have warned that greater cannabis "strength" could represent a health risk, others have noted that users readily learn to compensate by reducing their dosage, thus benefiting from reductions in smoking side-hazards such as heat shock or carbon monoxide.
Whole flower and leaf
The terms cannabis or marijuana generally refer to the dried flowers and subtending leaves and stems of the female cannabis plant. This is the most widely consumed form, containing 3% to 22% THC. In contrast, cannabis varieties used to produce industrial hemp contain less than 1% THC and are thus not valued for recreational use.
This is the stock material from which all other preparations are derived. It is noted that cannabis or its extracts must be sufficiently heated or dehydrated to cause decarboxylation of its most abundant cannabinoid, tetrahydrocannabinolic acid (THCA), into psychoactive THC.
Hashish (also spelled hasheesh, hashisha, or simply hash) is a concentrated resin cake or ball produced from pressed kief, the detached trichromes and fine material that fell off of Cannabis flowers and leaves. It varies in color from black to golden brown depending upon purity and variety of cultivar it was obtained from. It can be consumed orally or smoked.
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. Nabiximols is a branded product name from a tincture manufacturing pharmaceutical company.
Hash oil is obtained from the cannabis plant by solvent extraction, and contains the cannabinoids present in the natural oils of cannabis flowers and leaves. The solvents are evaporated to leave behind a very concentrated oil. Hemp oil is very different from both Hemp seed oil and Cannabis flower essential oil. Owing to its purity, these products are consumed by smoking, vaporizing, eating, or applied topically.
There are many varieties of cannabis infusions owing to the variety of non-volatile solvents used. 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.
Contaminants may be found in hashish obtained from "soap bar"-type sources. The dried flowers of the plant may be contaminated by the plant taking up heavy metals and other toxins from its growing environment, or by the addition of lead or glass beads, used to increase the weight or to make the cannabis appear as if it has more crystal-looking trichomes indicating a higher THC content.Iin the Netherlands, chalk has been used to make cannabis appear to be higher quality. Increasing the weight of hashish products in Germany with lead caused lead intoxication in at least 29 users.
Despite cannabis being generally perceived as a natural or "chemical-free" product, in a recent Australian survey one in four Australians consider cannabis grown indoors under hydroponic conditions to be a greater health risk due to increased contamination, added to the plant during cultivation to enhance the plant growth and quality.
Methods of consumption
Cannabis is consumed in many different ways:
- smoking, most of which involve inhaling vaporized cannabinoids ("smoke") from small pipes, bongs (portable version of hookah with water chamber), paper-wrapped joints or tobacco-leaf-wrapped blunts, roach clips, and other items.
- vaporizer heats herbal cannabis to 365–410 °F (185–210 °C), causing the active ingredients to evaporate into a vapor without burning the plant material (the boiling point of THC is 390.4 °F (199.1 °C) at 760 mmHg pressure).[not in citation given]
- Cannabis may be consumed orally in any form. Marijuana brownies recipes have been used in consumption by sub-culture groups.
- Cannabis tea has relatively small concentrations of THC because THC is an oil (lipophilic) and is only slightly water-soluble (with a solubility of 2.8 mg per liter). Cannabis tea is made by first adding a saturated fat to hot water (i.e. cream or any milk except skim) with a small amount of cannabis.
Mechanism of action
The high lipid-solubility of cannabinoids results in their persisting in the body for long periods of time. 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). A number of 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.
Until recently[when?], little was known about the specific mechanisms of action of THC at the neuronal level. However, researchers have now confirmed that THC exerts its most prominent effects via its actions on two types of cannabinoid receptors, the CB1 receptor and the CB2 receptor, both of which are G-Protein coupled receptors. 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 as well. 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. These actions can be blocked by the selective CB1 receptor antagonist SR141716A (rimonabant), which has been shown in clinical trials to be an effective treatment for smoking cessation, weight loss, and as a means of controlling or reducing metabolic syndrome risk factors. However, due to the dysphoric effect of CB1 antagonists, this drug is often discontinued due to these side effects.
Via CB1 activation, THC indirectly increases dopamine release and produces psychotropic effects. Cannabidiol also acts as an allosteric modulator of the mu and delta opioid receptors. THC also potentiates the effects of the glycine receptors. The role of these interactions in the "marijuana high" remains elusive.
Detection of consumption
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. 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. 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. Urine contains predominantly THC-COOH, while hair, oral fluid and sweat contain primarily THC. Blood may contain both substances, with the relative amounts dependent on the recency and extent of usage.
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. Despite this, it is common in the United States for prosecutors to seek plea bargains on the basis of positive D-L tests, claiming them definitive, or even to seek conviction without the use of gas chromatography confirmation, which can only be done in the lab. In 2011, researchers at John Jay College of Criminal Justice reported that dietary zinc supplements can mask the presence of THC and other drugs in urine. Similar claims have been made in web forums on that topic.
Cannabis is indigenous to Central and South Asia. Evidence of the inhalation of cannabis smoke can be found in the 3rd millennium BCE, as indicated by charred cannabis seeds found in a ritual brazier at an ancient burial site in present day Romania. In 2003, a leather basket filled with cannabis leaf fragments and seeds was found next to a 2,500- to 2,800-year-old mummified shaman in the northwestern Xinjiang Uygur Autonomous Region of China. Cannabis is also known to have been used by the ancient Hindus of India and Nepal thousands of years ago. The herb was called ganjika in Sanskrit (गांजा/গাঁজা ganja in modern Indo-Aryan languages). The ancient drug soma, mentioned in the Vedas, was sometimes associated with cannabis.
Cannabis was also known to the ancient Assyrians, who discovered its psychoactive properties through the Aryans. Using it in some religious ceremonies, they called it qunubu (meaning "way to produce smoke"), a probable origin of the modern word "cannabis". Cannabis was also introduced by the Aryans to the Scythians, Thracians and Dacians, whose shamans (the kapnobatai—"those who walk on smoke/clouds") burned cannabis flowers to induce a state of trance.
Cannabis has an ancient history of ritual use and is found in pharmacological cults around the world. Hemp seeds discovered by archaeologists at Pazyryk suggest early ceremonial practices like eating by the Scythians occurred during the 5th to 2nd century BCE, confirming previous historical reports by Herodotus. One writer has claimed that cannabis was used as a religious sacrament by ancient Jews and early Christians due to the similarity between the Hebrew word "qannabbos" ("cannabis") and the Hebrew phrase "qené bósem" ("aromatic cane"). It was used by Muslims in various Sufi orders as early as the Mamluk period, for example by the Qalandars.
A study published in the South African Journal of Science showed that "pipes dug up from the garden of Shakespeare's home in Stratford-upon-Avon contain traces of cannabis." The chemical analysis was carried out after researchers hypothesized that the "noted weed" mentioned in Sonnet 76 and the "journey in my head" from Sonnet 27 could be references to cannabis and the use thereof. Examples of classic literature featuring cannabis include Les paradis artificiels by Charles Baudelaire and The Hasheesh Eater by Fitz Hugh Ludlow.
John Gregory Bourke described use of "mariguan", which he identifies as Cannabis indica or Indian hemp, by Mexican residents of the Rio Grande region of Texas in 1894. He described its uses for treatment of asthma, to expedite delivery, to keep away witches, and as a love-philtre. He also wrote that many Mexicans added the herb to their cigarritos or mescal, often taking a bite of sugar afterward to intensify the effect. Bourke wrote that because it was often used in a mixture with toloachi (which he inaccurately describes as Datura stramonium), mariguan was one of several plants known as "loco weed". Bourke compared mariguan to hasheesh, which he called "one of the greatest curses of the East", citing reports that users "become maniacs and are apt to commit all sorts of acts of violence and murder", causing degeneration of the body and an idiotic appearance, and mentioned laws against sale of hasheesh "in most Eastern countries".
Cannabis was criminalized in various countries beginning in the early 20th century. In the United States, the first restrictions for sale of cannabis came in 1906 (in District of Columbia). It was outlawed in South Africa in 1911, in Jamaica (then a British colony) in 1913, and in the United Kingdom and New Zealand in the 1920s. Canada criminalized cannabis in the Opium and Drug Act of 1923, before any reports of use of the drug in Canada. 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".
In the United States in 1937, the Marihuana Tax Act was passed, and prohibited the production of hemp in addition to cannabis. The reasons that hemp was also included in this law are disputed—several scholars have claimed that the Act was passed in order to destroy U.S tiny hemp industry, with the primary involvement of businessmen Andrew Mellon, Randolph Hearst, and the Du Pont family. With the invention of the decorticator, hemp became a very cheap substitute for the paper pulp that was used in the newspaper industry and Hearst consequently believed that his extensive timber holdings were at threat. Mellon, Secretary of the Treasury and the wealthiest man in America at that time, had invested heavily in DuPont's new synthetic fiber, nylon, and believed that the replacement of the traditional resource, hemp, was integral to the new product's success.
Hemp was identified as a potential substitute for wood pulp but such claims were based on an inaccurate 1916 government report that concluded that "hemp hurds"—broken parts of the inner core of the hemp stem—were a suitable source for paper production. This has not been confirmed by later research, as the capacity of hemp hurds in such a context has not been established—many hemp advocates have greatly overestimated the proportion of useful cellulose in hemp hurds. In 2003, 95% of the hemp hurds in the European Union (EU) were used for animal bedding and only about 5% were used as building material.[dead link][dead link]
The United Nations' 2012 "Global Drug Report" stated that cannabis "was the world's most widely produced, trafficked, and consumed drug in the world in 2010", identifying that between 119 million and 224 million users existed in the world's adult (18 or older) population.
Since the beginning of the 20th century, most countries have enacted laws against the cultivation, possession or transfer of cannabis. These laws have impacted adversely on the cannabis plant's cultivation for non-recreational purposes, but there are many regions where, under certain circumstances, 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 has been historically tolerated, some new restrictions have been put in place, such as the closing of cannabis coffee shops near the borders of the Netherlands, closing of coffee shops near secondary schools in the Netherlands and crackdowns on "Pusher Street" in Christiania, Copenhagen in 2004.
Some jurisdictions use free voluntary treatment programs and/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. More recently however, many political parties, non-profit organizations and causes based on the legalization of medical cannabis and/or legalizing the plant entirely (with some restrictions) have emerged.
On December 6, 2012, the U.S. state of Washington became the first state to officially legalize cannabis in a state law ( but still illegal by federal law), with the state of Colorado following close behind. On January 1, 2013, the first marijuana "club" for private marijuana smoking (no buying or selling, however) was allowed for the first time in Colorado. The California Supreme Court decided in May 2013 that local governments can ban medical marijuana dispensaries despite a state law in California of 1996 state law that permits the use of weed for medical purposes; at least 180 cities across the state and Bay Area have enacted bans in recent years.
||It has been suggested that this article be merged with Cannabis. (Discuss) Proposed since January 2013.|
It is often claimed by growers and breeders of herbal cannabis that advances in breeding and cultivation techniques have increased the potency of cannabis since the late 1960s and early '70s, when THC was first discovered and understood. However, potent seedless cannabis such as "Thai sticks" were already available at that time. Sinsemilla (Spanish for "without seed") is the dried, seedless inflorescences 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. 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. It is often cited that the average levels of THC in cannabis sold in United States rose dramatically between the 1970s and 2000, but such statements are likely skewed because of undue weight given to much more expensive and potent, but less prevalent samples.
"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%.
The price or street value of cannabis varies widely depending on geographic area and potency.
In the United States, cannabis is overall the #4 value crop, and is #1 or #2 in many states including California, New York and Florida, averaging $3,000/lb. It is believed to generate an estimated $36 billion market. Most of the money is spent not on growing and producing but on smuggling the supply to buyers. The United Nations Office on Drugs and Crime claims in its 2008 World Drug Report that typical U.S. retail prices are $10–15 per gram (approximately $280–420 per ounce). Street prices in North America are known to range from about $150 to $400 per ounce, depending on quality.
The European Monitoring Centre for Drugs and Drug Addiction reports that typical retail prices in Europe for cannabis varies from 2€ to 20€ per gram, with a majority of European countries reporting prices in the range 4–10€. In the United Kingdom, a cannabis plant has an approximate street value of £300, but retails to the end-user at about £160/oz.
^ a: Weed, pot, grass, and herb are among the many other nicknames for marijuana or cannabis as a drug.
^ b: Sources for this section and more information can be found in the Medical cannabis article
- A. ElSohly, Mahmoud (2007). Marijuana and the Cannabinoids. Humana Press. p. 8. ISBN 1-58829-456-0.
- See article on Marijuana as a word.
- Shorter Oxford English Dictionary (6th ed.), Oxford University Press, 2007, ISBN 978-0-19-920687-2
- See, Etymology of marijuana.
- Company, Houghton Mifflin; American Heritage Dictionaries (2007-11-14). Spanish Word Histories and Mysteries. Houghton Mifflin Harcourt. p. 142. ISBN 978-0-618-91054-0.
- "What chemicals are in marijuana and its byproducts?". ProCon.org. 2009. Retrieved 2013-01-13.
- Franjo Grotenhermen, Ethan Russo (2002). Cannabis and Cannabinoids: Pharmacology, Toxicology, and Therapeutic Potential. London: Routledge. p. 28. ISBN 978-0-7890-1508-2.
- El-Alfy, Abir T, et al. (Jun 2010). "Antidepressant-like effect of delta-9-tetrahydrocannabinol and other cannabinoids isolated from Cannabis sativa L". Pharmacology Biochemistry and Behavior 95 (4): 434–42. doi:10.1016/j.pbb.2010.03.004. PMC 2866040. PMID 20332000.
- Fusar-Poli P, Crippa JA, Bhattacharyya S, et al. (January 2009). "Distinct effects of delta-9-tetrahydrocannabinol and Cannabidiol on Neural Activation during Emotional Processing". Archives of General Psychiatry 66 (1): 95–105. doi:10.1001/archgenpsychiatry.2008.519. PMID 19124693.
- Rudgley, Richard (1998). Lost Civilisations of the Stone Age. New York: Free Press. ISBN 0-684-85580-1.
- United Nations Office on Drugs and Crime (2006). "Cannabis: Why We Should Care" (PDF). World Drug Report 1 (S.l.: United Nations). p. 14. ISBN 92-1-148214-3.
- "Topics In Brief: Marijuana". National Institute on Drug Abuse.
- "Cannabis: Legal Status". Erowid.org. Retrieved 2011-10-30.
- UNODC. World Drug Report 2010. United Nations Publication. p. 198. Retrieved 2010-07-19.
- "Marijuana and the Brain, Part II: The Tolerance Factor".[unreliable source?]
- M. Szalavitz (2011-09-08). "Marijuana Slims? Why Pot Smokers Are Less Obese". Time.com.
- Riedel, G.; Davies, S.N. (2005). "Cannabinoid function in learning, memory and plasticity". Handb Exp Pharmacol. Handbook of Experimental Pharmacology 168: 446. doi:10.1007/3-540-26573-2_15. ISBN 3-540-22565-X. PMID 16596784.
- L. Iversen (Feb 2005). "Long-term effects of exposure to cannabis". Current Opinion in Pharmacology 5 (1): 69–72. doi:10.1016/j.coph.2004.08.010. PMID 15661628.
- H. Kalant (Aug 2004). "Adverse effects of cannabis on health: an update of the literature since 1996". Progress in Neuro-Psychopharmacology and Biological Psychiatry 28 (5): 849–63. doi:10.1016/j.pnpbp.2004.05.027. PMID 15363608.
- Marijuana use and mortality. PBS. 1996-06-28. Retrieved 2013-01-05.
- Stafford, Peter (1992). Psychedelics Encyclopedia. Berkeley, California, United States: Ronin Publishing, Inc. ISBN 0-914171-51-8.
- McKim, William A (2002). Drugs and Behavior: An Introduction to Behavioral Pharmacology (5 ed.). Prentice Hall. p. 400. ISBN 0-13-048118-1.
- "Information on Drugs of Abuse". Commonly Abused Drug Chart. nih.gov.
- "FDA: Inter-Agency Advisory Regarding Claims That Smoked Marijuana Is a Medicine". Fda.gov. Retrieved 2011-03-26.
- "18 Legal Medical Marijuana States and DC". ProCon.org. 2012-12-06. Retrieved 2013-01-07.
- "FDA: Inter-Agency Advisory Regarding Claims That Smoked Marijuana Is a Medicine". FDA.gov. 2006. Retrieved 2010-09-20.
- "Frequently Asked Questions – Medical Marihuana". Hc-sc.gc.ca. Retrieved 2010-01-02.
- McLaren, Jennifer; Lemon, Jim; Robins, Lisa; Mattick, Richard P. (February 2008). Cannabis and Mental Health: Put into Context. National Drug Strategy Monograph Series. Australian Government Department of Health and Ageing. Retrieved 17 October 2009.
- Harding, Anne (2008-11-03). "Pot-induced psychosis may signal schizophrenia". Reuters. Retrieved 2013-01-03.
- Henquet, C.; Krabbendam, L.; Spauwen, J.; Kaplan, C.; Lieb, R.; Wittchen, H. -U.; Van Os, J. (2005). "Prospective cohort study of cannabis use, predisposition for psychosis, and psychotic symptoms in young people". BMJ 330 (7481): 11. doi:10.1136/bmj.38267.664086.63. PMC 539839. PMID 15574485.
- Simeon, Daphne (2004). "Depersonalization disorder: a contemporary overview". CNS Drugs 18 (6): 343–54. doi:10.2165/00023210-200418060-00002. PMID 15089102.
- "The BEACH Project". Retrieved 17 October 2009.
- Lester Grinspoon (2008). "Cannabis and Schizophrenia". Scribd.com. Retrieved 2013-01-07.
- Stokes PR, Mehta MA, Curran HV, Breen G, Grasby PM. (15 October 2009). "Can recreational doses of THC produce significant dopamine release in the human striatum?". NeuroImage 48 (1): 186–90. doi:10.1016/j.neuroimage.2009.06.029. PMID 19539765.
- Could smoking pot cut risk of head, neck cancer?. Reuters. 2009-08-25. Retrieved 2013-01-07.
- "Relative Addictiveness of Drugs". The New York Times. Tfy.drugsense.org. 1994-08-02. Retrieved 2013-01-03.
- Meier MH, et al. (2012-07-30). "Persistent cannabis users show neuropsychological decline from childhood to midlife". PNAS 109 (40): E2657. doi:10.1073/pnas.1206820109.
- "Persistent Cannabis Users Show Neuropsychological Decline from Childhood to Midlife". JournalistsResource.org. Retrieved 2012-08-29.
- Ole Rogeberg (2013-01-14). "Correlations between cannabis use and IQ change in the Dunedin cohort are consistent with confounding from socioeconomic status". PNAS. doi:10.1073/pnas.1215678110.
- "Does pot really lower IQ? It's not so simple". Vitals.nbcnews.com. 2013-01-14. Retrieved 2013-01-25.
- "Pot smokers might not turn into dopes after all". Nature.com. 2013-01-14. Retrieved 2013-01-25.
- Zalesky A, et al. (Jul 2012). "Effect of long-term cannabis use on axonal fibre connectivity". Brain 135 (7): 2245–55. doi:10.1093/brain/aws136. PMID 22669080.
- "Teen marijuana use may show no effect on brain tissue, unlike alcohol, study finds". Huffingtonpost.com. 2012-12-21. Retrieved 2013-01-03.
- RAND study casts doubt on claims that marijuana acts as "gateway" to the use of cocaine and heroin. RAND Corporation. 2002-12-02. Archived from the original on 2006-11-04.
- Lundin, Leigh (2009-03-01). The Great Smoke-Out. Criminal Brief.[dubious ]
- Torabi MR, Bailey WJ, Majd-Jabbari M (1993). "Cigarette Smoking as a Predictor of Alcohol and Other Drug Use by Children and Adolescents: Evidence of the "Gateway Drug Effect"". The Journal of School Health 63 (7): 302–6. doi:10.1111/j.1746-1561.1993.tb06150.x. PMID 8246462.
- Australian Government Department of Health: National Cannabis Strategy Consultation Paper, p. 4. "Cannabis has been described as a 'Trojan Horse' for nicotine addiction, given the usual method of mixing Cannabis with tobacco when preparing marijuana for administration."
- Hall WD, Lynskey M (January 2005). "Is Cannabis A Gateway Drug? Testing Hypotheses About the Relationship Between Cannabis Use and the Use of Other Illicit Drugs". Drug and Alcohol Review 24 (1): 39–48. doi:10.1080/09595230500126698. PMID 16191720.
- Saitz, Richard (2003-02-18). "Is marijuana a gateway drug?". Journal Watch 2003 (218): 1.
- Degenhardt, Louisa et al. (2007). "Who are the new amphetamine users? A 10-year prospective study of young Australians". Addiction 102 (8): 1269–79. doi:10.1111/j.1360-0443.2007.01906.x. PMID 17624977.
- Morral AR, McCaffrey DF, Paddock SM (2002). "Reassessing the marijuana gateway effect". Addiction 97 (12): 1493–504. doi:10.1046/j.1360-0443.2002.00280.x. PMID 12472629.
- "Marijuana Policy Project- FAQ". Archived from the original on 2008-06-22.
- Ellgren, Maria (9 February 2007). Neurobiological effects of early life cannabis exposure in relation to the gateway hypothesis (in English and Swedish). Stockholm. ISBN 978-91-7357-064-0.
- Ellgren, Maria; Spano, Sabrina M; Hurd, Yasmin L (2006). "Adolescent Cannabis Exposure Alters Opiate Intake and Opioid Limbic Neuronal Populations in Adult Rats". Neuropsychopharmacology 32 (3): 607–615. doi:10.1038/sj.npp.1301127. PMID 16823391.
- "Risk of marijuana's 'gateway effect' overblown, new research shows". Sciencedaily.com. 2010-09-02. Retrieved 2010-09-20.
- "Minimal long-term effects of marijuana use found in central nervous system by UCSD researchers". Health.ucsd.edu. 2003-06-27. Retrieved 2012-12-31.
- Deena Beasley (2003-06-27). "Study – Pot doesn't cause permanent brain damage". Reuters. Retrieved 2012-12-31.
- Yann Le Strat, Bernard Le Foll (2011-08-24). "Obesity and cannabis use: results from 2 representative national surveys". Am. J. Epidemiol. 174 (8): 929–33. doi:10.1093/aje/kwr200. PMID 21868374.
- Does pot prevent obesity? What new marijuana study says. CBS News. 2011-09-07. Retrieved 2013-01-09.
- Szalavitz, Maia (2011-09-08). "Marijuana slims? Why pot smokers are less obese". TIME.com. Retrieved 2013-01-09.
- Cannabis could be used to treat obesity-related diseases. Telegraph. 2012-07-08. Retrieved 2013-01-09.
- Mark Pletcher et al. (2012-05-02). "Association between marijuana exposure and pulmonary function over 20 years". JAMA 307 (2): 173–81. doi:10.1001/jama.2011.1961.
- Kim, Leland (2012-01-10). "Marijuana shown to be less damaging to lungs than tobacco". UCSF.edu. Retrieved 2013-01-25.
- "Study finds no cancer-marijuana connection". Washingtonpost.com. 2006-05-25. Retrieved 2013-01-25.
- O'Connor, Anahad (2012-01-11). "Moderate marijuana use does not impair lung function, study finds". NYTimes.com. Retrieved 2013-01-25.
- Szalavitz, Maia (2012-01-10). "Study: smoking marijuana not linked with lung damage". TIME.com. Retrieved 2013-01-25.
- Szalavitz, Maia (2012-06-14). "Marijuana doesn't increase risk of lung cancer, mental illness or death". Time.com. Retrieved 2013-01-02.[dubious ]
- Calabria B, et al. (May 2010). "Does cannabis use increase the risk of death? Systematic review of epidemiological evidence on adverse effects of cannabis use". Drug Alcohol Rev. 29 (3): 318–30. doi:10.1111/j.1465-3362.2009.00149.x. PMID 20565525.
- Aranya, A; Williams, M (2007). "Marijuana as a trigger of cardiovascular events: Speculation or scientific certainty?". International Journal of Cardiology 118 (2): 141–147. Retrieved 31 January 2013.
- Walker, J.Michael; Huang, Susan M (2002). "Cannabinoid analgesia". Pharmacology & Therapeutics 95 (2): 127–35. doi:10.1016/S0163-7258(02)00252-8. "... to date, there are no deaths known to have resulted from overdose of cannabis. (p. 128)"
- Jones, R. T. (2002). "Cardiovascular system effects of marijuana". Journal of clinical pharmacology 42 (11 Suppl): 58S–63S. PMID 12412837.
- David J Nutt, et al. (Nov 2010). "Drug harms in the UK: a multicriteria decision analysis". The Lancet 376 (9752): 1558–65. doi:10.1016/S0140-6736(10)61462-6. PMID 21036393.
- "Puffing is the best medicine". Articles.latimes.com. 2006-05-05. Retrieved 2013-01-25.
- Susan E. Matthews (2012-07-03). "Toddler's marijuana cookie ingestion was harmless, expert says". MyHealthNewsDaily.com. Retrieved 2013-01-02.
- "Mortality data from the Drug Abuse Warning Network". ProCon.org. 2001. Retrieved 2013-01-05.
- "Deaths from Marijuana v. 17 FDA-Approved Drugs". ProCon.org. 2005. Retrieved 2013-01-05.
- W. Hall, N. Solowij (1998-11-14). "Adverse effects of cannabis". Lancet 352 (9140): 1611–16. doi:10.1016/S0140-6736(98)05021-1. PMID 9843121.
- Dave Smith (2012-08-08). "Medical marijuana: 10 health benefits that legitimize legalization". Ibtimes.com. Retrieved 2012-12-31.
- Kochanowski, M.; Kała, M. (2005). "Tetrahydrocannabinols in clinical and forensic toxicology". Przeglad lekarski 62 (6): 576–580. PMID 16225128.
- Wade, D. (2012). "Evaluation of the safety and tolerability profile of Sativex®: Is it reassuring enough?". Expert Review of Neurotherapeutics 12 (4s): 9–5. doi:10.1586/ern.12.12. PMID 22509986.
- Gumbiner, Jann (2011-02-17). Does Marijuana Cause Cancer?. Psychology Today. Retrieved 2013-01-09.
- Does smoking cannabis cause cancer?. Cancer Research UK. 2010-09-20. Retrieved 2013-01-09.
- Tashkin, Donald (March 1997). Effects of marijuana on the lung and its immune defenses. UCLA School of Medicine. Retrieved 2012-06-23.
- "Chemicals known to the state to cause cancer or reproductive toxicity". ca.gov. 2012-07-20. Retrieved 2013-01-08.
- The impact of cannabis on your lungs. British Lung Association. June 2012. Retrieved 2013-01-09.
- Nutt, Professor David (2012-06-11). "Smoke without fire? Scaremongering by the British Lung Foundation over cannabis vs tobacco : Evidence not Exaggeration". Profdavidnutt.wordpress.com. Retrieved 2013-01-25.
- Hashibe, M.; Morgenstern, H.; Cui, Y.; Tashkin, D. P.; Zhang, Z. -F.; Cozen, W.; Mack, T. M.; Greenland, S. (2006). "Marijuana Use and the Risk of Lung and Upper Aerodigestive Tract Cancers: Results of a Population-Based Case-Control Study". Cancer Epidemiology Biomarkers & Prevention 15 (10): 1829–1834. doi:10.1158/1055-9965.EPI-06-0330. PMID 17035389.
- "Marijuana Research". scientificamerican.com. 2004-11-22. Retrieved 2013-01-15.
- Laura L. Boles Ponto (May 2006). "Challenges of marijuana research". Brain 129 (5): 1081–3. doi:10.1093/brain/awl092.
- Alok Jha (2012-05-31). Ecstasy and cannabis should be freely available for study, says David Nutt. The Guardian. Retrieved 2013-01-15.
- "Medical Marijuana Policy in the United States". Stanford.edu. 2012-05-15. Retrieved 2013-01-15.
- "Research into marijuana's medical benefits limited; scientists cite challenge of studying an illegal drug". bostonglobe.com. 2012-10-19. Retrieved 2013-01-15.
- Lyle E. Craker, Ph. D. v. U.S. Drug Enforcement Administration, Docket No. 05-16, May 8, 2006, 8–27 PDF
- People Working to Legalize Medical Marijuana, ACLU, 2005-11-29, retrieved 2010-03-05
- J. E. Joy, S. J. Watson, Jr., and J. A. Benson, Jr. (1999). Marijuana and Medicine: Assessing The Science Base. Washington, D.C.: National Academy of Sciences Press. ISBN 0-585-05800-8.
- Why Does Cannabis Potency Matter?. United Nations Office on Drugs and Crime. 2009-06-29.
- ElSohly MA, Ross SA, Mehmedic Z, Arafat R, Yi B, Banahan BF (January 2000). "Potency Trends of delta9-THC and Other Cannabinoids in Confiscated Marijuana from 1980 to 1997". Journal of Forensic Sciences 45 (1): 24–30. PMID 10641915.
- Olemiss.edu[dead link]
- Cannabis Potency. National Cannabis Prevention and Information Centre. Retrieved 2011-12-13.
- "BBC: Cannabis laws to be strengthened. May 2008 20:55 UK". BBC News. 2008-05-07. Retrieved 2010-09-20.
- Di Forti, M; Morgan, C; Dazzan, P; Pariante, C; Mondelli, V; Marques, TR; Handley, R; Luzi, S et al. (2009). "High-potency cannabis and the risk of psychosis". British Journal of Psychiatry 195 (6): 488–91. doi:10.1192/bjp.bp.109.064220. PMC 2801827. PMID 19949195. Retrieved 2010-01-02.
- Hope, Christopher (2008-02-06). "Use of extra strong 'skunk' cannabis soars". The Daily Telegraph (London).
- "High Times in Ag Science: Marijuana More Potent Than Ever". Wired.com. 2008-12-22. Retrieved 2010-01-02.
- "Marijuana". dictionary.reference.com.
- "Hemp Facts". Naihc.org. Retrieved 2013-01-09.
- "Decarboxylation – Does Marijuana Have to be Heated to Become Psychoactive?". Cannabisculture.com. 2003-01-02. Retrieved 2012-10-09.
- "Kief". Cannabisculture.com. 2005-03-09. Retrieved 2010-01-02.
- "Hashish". dictionary.reference.com.
- "Hash Oil Info". a1b2c3.com.
- Soapbar – Just Say No to polluted hash[unreliable medical source?]
- Flin Flon Mine Area Marijuana Contamination, Medicalmarihuana.ca, retrieved 2011-04-20
- "Warnings over glass in cannabis". BBC News. 2007-02-01. Retrieved 2010-05-23.
- "Electronenmicroscopisch onderzoek van vervuilde wietmonsters".
- Busse F, Omidi L, Timper K, et al. (April 2008). "Lead poisoning due to adulterated marijuana". N. Engl. J. Med. 358 (15): 1641–2. doi:10.1056/NEJMc0707784. PMID 18403778.
- Hall, W.; Nelson, J. (1995). Public perceptions of the health and psychological consequences of cannabis use. Canberra: Australian Government Publishing Service. ISBN 978-0-644-42830-9.[page needed]
- StollzNow (2006). Market research report: Australians on cannabis. Report prepared for NDARC and Pfizer Australia. Sydney: StollzNow Research and Advisory.[page needed]
- THC. ChemSpider.
- Dronabinol in the ChemIDplus database
- Leo E. Hollister, et al. (March 1986). "Health aspects of cannabis". Pharma Review (38): 1–20. Archived from the original on 1986. Retrieved 2011-02-17.
- Wilson, R. & Nicoll, A. (2002). "Endocannabinoid signaling in the brain". Science 296 (5568): 678–682. doi:10.1126/science.1063545. PMID 11976437.
- Fernandez, J. & Allison, B. (2004). "Rimbonabant Sanofi-Synthelabo". Current Opinion in Investigational Drugs (5): 430–435.
- Kathmann, Markus; Flau, Karsten; Redmer, Agnes; Tränkle, Christian; Schlicker, Eberhard (2006). "Cannabidiol is an allosteric modulator at mu- and delta-opioid receptors". Naunyn-Schmiedeberg's Archives of Pharmacology 372 (5): 354–361. doi:10.1007/s00210-006-0033-x. PMID 16489449.
- Nadia Hejazi, Chunyi Zhou, Murat Oz, Hui Sun, Jiang Hong Ye, Li Zhang (March 2006). "Δ9-tetrahydrocannabinol and endogenous cannabinoid anandamide directly potentiate the function of glycine peceptors". Molecular Pharmacology 69 (3): 991–7. doi:10.1124/mol.105.019174. PMID 16332990.
- R. Baselt, Disposition of Toxic Drugs and Chemicals in Man, 8th edition, Biomedical Publications, Foster City, CA, 2008, pp 1513–1518.
- Coulter C, Taruc M, Tuyay J, Moore C (2009). "Quantitation of tetrahydrocannabinol in hair using immunoassay and liquid chromatography with tandem mass spectrometric detection". Drug Test. Anal. 1 (5): 234–39. doi:10.1002/dta.40. PMID 20355201.
- DM Schwope, G Milman, MA Huestis (2010). "Validation of an enzyme immunoassay for detection and semiquantification of cannabinoids in oral fluid". Clin. Chem. 56 (6): 1007–1014. doi:10.1373/clinchem.2009.141754. PMC 3159868. PMID 20360126.
- Huestis MA, Scheidweiler KB, Saito T, Fortner N, Abraham T, Gustafson RA, Smith ML (2008). "Excretion of Δ9-Tetrahydrocannabinol in Sweat". Forensic Sci. Int. 174 (2–3): 173–177. doi:10.1016/j.forsciint.2007.04.002. PMC 2277330. PMID 17481836.
- John Kelly (2010-06-28). Has the most common marijuana test resulted in tens of thousands of wrongful convictions?. AlterNet.
- Venkatratnam, Abhishek; Nathan H. Lents (July 2011). "Zinc Reduces the Detection of Cocaine, Methamphetamine, and THC by ELISA Urine Testing". Journal of Analytical Toxicology 35 (6): 333–340. doi:10.1093/anatox/35.6.333. PMID 21740689.
- Matthews, A; Matthews, L (2007). Learning Chinese Characters. p. 336. ISBN 978-0-8048-3816-0.
- Stafford, Peter (1992). Psychedelics Encyclopedia. Berkeley, CA, USA: Ronin Publishing. ISBN 0-914171-51-8.
- "Marijuana and the Cannabinoids", ElSohly (p. 8).
- Lab work to identify 2,800-year-old mummy of shaman. People's Daily Online. 2006.
- Hong-En Jiang, et al. (2006). "A new insight into Cannabis sativa (Cannabaceae) utilization from 2500-year-old Yanghai tombs, Xinjiang, China". Journal of Ethnopharmacology 108 (3): 414–22. doi:10.1016/j.jep.2006.05.034. PMID 16879937.
- Leary, Timothy (1990). Tarcher & Putnam, ed. Flashbacks. New York: GP Putnam's Sons. ISBN 0-87477-870-0.
- Miller, Ga (1911). "Encyclopædia Britannica". Science 34 (883) (11 ed.). pp. 761–2. doi:10.1126/science.34.883.761. PMID 17759460.
- Rudgley, Richard (1998). Little, Brown, et al, ed. The Encyclopedia of Psychoactive Substances. ISBN 0-349-11127-8.
- Franck, Mel (1997). Marijuana Grower's Guide. Red Eye Press. p. 3. ISBN 0-929349-03-2.
- Rubin, Vera D (1976). Cannabis and Culture. Campus Verlag. p. 305. ISBN 3-593-37442-0.
- Cunliffe, Barry W (2001). The Oxford Illustrated History of Prehistoric Europe. Oxford University Press. p. 405. ISBN 0-19-285441-0.
- Walton, Robert P (1938). Marijuana, America's New Drug Problem. JB Lippincott. p. 6.
- Matthew J. Atha (Independent Drug Monitoring Unit). "Types of Cannabis Available in the United Kingdom (UK)".
- "Cannabis linked to Biblical healing". News (BBC). 2003-01-06. Retrieved 2009-12-31.
- Ibn Taymiyya (2001). Le haschich et l'extase (in FR). Beyrouth: Albouraq. ISBN 2-84161-174-4.
- "Bard 'used drugs for inspiration'". BBC News. 2001-03-01. Retrieved 2009-08-07.
- "Drugs clue to Shakespeare's genius". CNN (Turner Broadcasting System). 2001-03-01. Retrieved 2009-08-07.
- John G. Bourke (1984-01-05). "Popular medicine, customs, and superstitions of the Rio Grande". Journal of American folklore 7–8: 138.
- "(Record of "marijuan" sample submitted by Bourke to the National Museum, 1892)".
- Bourke cites an anonymous writer in the "Evening Star", Washington, D. C., January 13, 1894 for additional remarks on the use of mariguan and Jamestown weed by inhabitants of the area.
- Statement of Dr. William C. Woodward. Drug library. Retrieved 2010-09-20.
- "Debunking the Hemp Conspiracy Theory".
- W. W. Willoughby (1925). Opium as an international problem. Baltimore: The Johns Hopkins Press. Retrieved 2010-09-20.
- Opium as an international problem: the Geneva conferences – Westel Woodbury Willoughby at Google Books
- French, Laurence; Manzanárez, Magdaleno (2004). NAFTA & neocolonialism: comparative criminal, human & social justice. University Press of America. p. 129. ISBN 978-0-7618-2890-7.
- Earlywine, 2005: p. 24
- Peet, 2004: p. 55
- Sterling Evans (2007). Bound in twine: the history and ecology of the henequen-wheat complex for Mexico and the American and Canadian Plains, 1880–1950. Texas A&M University Press. p. 27. ISBN 978-1-58544-596-7.
- Evans, Sterling, ed. (2006). The borderlands of the American and Canadian Wests: essays on regional history of the forty-ninth parallel. University of Nebraska Press. p. 199. ISBN 978-0-8032-1826-0.
- Gerber, Rudolph Joseph (2004). Legalizing marijuana: drug policy reform and prohibition politics. Greenwood Publishing Group. p. 7. ISBN 978-0-275-97448-0.
- Earleywine, Mitchell (2005). Understanding marijuana: a new look at the scientific evidence. Oxford University Press. p. 231. ISBN 978-0-19-518295-8.
- Robinson, Matthew B & Scherlen, Renee G (2007). Lies, damned lies, and drug war statistics: a critical analysis of claims made by the office of National Drug Control Policy. SUNY Press. p. 12. ISBN 978-0-7914-6975-0.
- Rowe, Thomas C (2006). Federal narcotics laws and the war on drugs: money down a rat hole. Psychology Press. p. 26. ISBN 978-0-7890-2808-2.
- Sullivan, Larry E et al, ed. (2005). Encyclopedia of Law Enforcement: Federal. SAGE. p. 747. ISBN 978-0-7619-2649-8.
- Lusane, Clarence (1991). Pipe dream blues: racism and the war on drugs. South End Press. pp. 37–8. ISBN 978-0-89608-410-0.
- Lyster H. Dewey and Jason L. Merrill Hemp Hurds as Paper-Making Material USDA Bulletin No. 404, Washington, DC, October 14, 1916, p. 25.
- "Hayo MG van der Werf: Hemp facts and hemp fiction". Hempfood.com. Retrieved 2011-10-30.[dead link]
- "Dr. Ivan BÛcsa, GATE Agricultural Research Institute, Kompolt — Hungary, Book Review Re-discovery of the Crop Plant Cannabis Marihuana Hemp (Die Wiederentdeckung der Nutzplanze Cannabis Marihuana Hanf)". Hempfood.com. Retrieved 2011-10-30.[dead link]
- Karus, Michael (2004). "European Hemp Industry 2002 – Cultivation, Processing and Product Lines". Journal of Industrial Hemp 9 (2). doi:10.1300/J237v09n02_10. Retrieved 16 March 2013.
- Eliana Dockterman (29). "Marijuana Now the Most Popular Drug in the World". Time NewsFeed. Time Inc. Retrieved 16 March 2013.
- "Many Dutch coffee shops close as liberal policies change, Exaptica". Expatica.com. 2007-11-27. Retrieved 2010-09-20.
- EMCDDA Cannabis reader: Global issues and local experiences, Perspectives on Cannabis controversies, treatment and regulation in Europe, 2008, p. 157.
- "43 Amsterdam coffee shops to close door", Radio Netherlands, Friday 21 November 2008[dead link]
- Luncheon with Gil Kerlikowske at National Press Club, April 17, 2013
- Marijuana goes legal in Washington state amid mixed messages. Reuters. Retrieved December 14, 2012.
- Alan Duke (2012-11-08). "2 states legalize pot, but don't 'break out the Cheetos' yet". CNN.com. Retrieved 2013-01-02.
- "Marijuana clubs ring in new year in Colorado as legalized pot smoking begins". Abcnews.go.com. 2013-01-01. Retrieved 2013-01-02.
- Horward Mintz (2013-05-06). "Medical pot: California Supreme Court allows cities to ban weed dispensaries". Marin Independent Journal.
- Daniel Forbes (2002-11-19). "The Myth of Potent Pot". Slate.com.
- World Drug Report 2006. United Nations Office on Drugs and Crime. Ch. 2.3.
- "Cannabis: Wholesale, street prices and purity levels" (PDF). UNODC.org. 2005. Retrieved 2013-01-09.
- Report on U.S. Domestic Marijuana Production. NORML. Retrieved 2010-01-02.
- Marijuana Crop Reports. NORML. Retrieved 2010-01-02.
- Marijuana Called Top U.S. Cash Crop. 2008 ABCNews Internet Ventures.
- United Nations Office on Drugs and Crime (2008). World drug report (PDF). United Nations Publications. p. 264. ISBN 978-92-1-148229-4.
- European Monitoring Centre for Drugs and Drug Addiction (2008). Annual report: the state of the drugs problem in Europe (PDF). Luxembourg: Office for Official Publications of the European Communities. p. 38. ISBN 978-92-9168-324-6.
- "Dearne Safer Neighbourhood Team (SNT) recovers cannabis with a street value of approximately £9,000". southyorks.police.uk. 2009-04-23. Archived from the original on 2011-11-26.
- Weed – Definition. Merriam-Webster Dictionary. Retrieved 2012-10-09.
- Pot – Definition. Merriam-Webster Dictionary. Retrieved 2012-10-09.
- Grass – Definition. Merriam-Webster Dictionary. Retrieved 2012-10-09.
- Herb – Definition. Merriam-Webster Dictionary. Retrieved 2012-10-09.
- "Marijuana Dictionary".
- Booth, Martin (2005). Cannabis: A History. Macmillan Publishers & Random House, Inc. ISBN 978-0-312-42494-7.
- Deitch, Robert (2003). Hemp: American history revisited: the plant with a divided history. Algora Pub. ISBN 0-87586-206-3.
- Earleywine, Mitchell (2005). Understanding marijuana: a new look at the scientific evidence. Oxford University Press. ISBN 0-19-513893-7.
- Emmett, David; Graeme Nice (2009). What you need to know about cannabis: understanding the facts. Jessica Kingsley Publishers. ISBN 1-84310-697-3.
- Geoffrey William, Guy; Brian Anthony Whittle, Philip Robson (2004). The medicinal uses of cannabis and cannabinoids. Pharmaceutical Press. ISBN 0-85369-517-2.
- Holland, Julie M.D. (2010). The pot book : a complete guide to cannabis : its role in medicine, politics, science, and culture. Park Street Press. ISBN 978-1-59477-368-6.
- Iversen, Leslie L (2008). The science of marijuana (2nd ed.). Oxford University Press. ISBN 978-0-19-532824-0.
- Jenkins, Richard (2006). Cannabis and young people: reviewing the evidence. Jessica Kingsley. ISBN 1-84310-398-2.
- Lambert, Didier M (2008). Cannabinoids in Nature and Medicine. Wiley-VCH. ISBN 3-906390-56-X.
- Roffman, Roger A; Robert S. Stephens (2006). Cannabis dependence: its nature, consequences, and treatment. Cambridge University Press. ISBN 0-521-81447-2.
- Russo, Ethan; Melanie Creagan Dreher, Mary Lynn Mathre (2004). Women and cannabis: medicine, science, and sociology. Haworth Press. ISBN 0-7890-2101-3.
- Solowij, Nadia (1998). Cannabis and cognitive functioning. Cambridge University Press. ISBN 0-521-59114-7.
|Look up Marijuana in Wiktionary, the free dictionary.|
|Wikimedia Commons has media related to: Cannabis|
- Wiktionary Appendix of Cannabis Slang
- Montana PBS documentary,Clearing the Smoke
- Cannabis (Marijuana) – Erowid
- Reefer Madness!—slideshow by Life magazine
- "Cannabis: a health perspective and research agenda", Programme on Substance Abuse, World Health Organization, 1997