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Cannabis, [b] also known as marijuana[c] or weed, among other names, is a non-chemically uniform drug from the cannabis plant. Native to Central or South Asia, the cannabis plant has been used as a drug for both recreational and entheogenic purposes and in various traditional medicines for centuries.
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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.
Cannabis, also known as marijuana, weed, sativa, and indica (as well as other names) [a] is a psychoactive drug from the Cannabis plant used for medical or recreational purposes. [18] [19] [20] (in legalized states).
- Overview
- Physical effects
- Tetrahydrocannabinol (THC)
- Legality
Marijuana is a drug composed of the leaves and flowers of plants in the genus Cannabis. Documented as far back as 2700 BCE in China, marijuana has long been considered valuable as an analgesic, an anesthetic, an antidepressant, an antibiotic, and a sedative.
What is the active ingredient in marijuana?
Tetrahydrocannabinol (THC) is the active ingredient present in all parts of both the male and female marijuana plants, but it is most concentrated in the resin (cannabin) in the flowering tops of the female plant. It was first isolated from the Indian hemp plant (Cannabis sativa) and synthesized in 1965.
What are the medical uses of marijuana?
Medical research has found marijuana useful in lowering internal eye pressure in persons suffering from glaucoma and providing relief from nausea and vomiting caused by treatments given to cancer and AIDS patients. It is also known to reduce muscle pain associated with multiple sclerosis and prevent epileptic seizures in some patients.
What are the effects of consuming or smoking marijuana?
Mentioned in a Chinese herbal dating from 2700 bce, marijuana has long been considered valuable as an analgesic, an anesthetic, an antidepressant, an antibiotic, and a sedative. Although it was usually used externally (e.g., as a balm or smoked), in the 19th century ce its tips were sometimes administered internally to treat gonorrhea and angina pectoris.
Marijuana’s effects vary, depending upon the strength and amount consumed, the setting in which it is taken, and the experience of the user. Psychological effects tend to predominate, with the user commonly experiencing a mild euphoria. Alterations in vision and judgment result in distortions of time and space. Acute intoxication may occasionally induce visual hallucinations, anxiety, depression, extreme variability of mood, paranoid reactions, and psychoses lasting four to six hours. Marijuana’s physical effects include reddening of the eyes, dryness of the mouth and throat, moderate increase in the rapidity of the heartbeat, tightness of the chest (if the drug is smoked), drowsiness, unsteadiness, and muscular incoordination.
The worldwide use of marijuana and hashish as intoxicants has raised various medical and social questions, many of which have been under continuing scientific investigation, especially since the mid-1960s, when THC was first isolated and produced synthetically. Research was directed toward identifying the short- and long-term physical effects of marijuana. In the late 20th and early 21st centuries, medical research revealed various therapeutic effects of marijuana and THC. They were found to be useful in lowering internal eye pressure in persons suffering from glaucoma and in alleviating nausea and vomiting caused by chemotherapeutic drugs used to treat cancer patients and those with AIDS. Marijuana also has been found to reduce the muscle pain associated with multiple sclerosis and to prevent epileptic seizures in some patients.
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In the late 1980s researchers discovered a receptor for THC and THC-related chemicals in the brains of certain mammals, including humans. This finding indicated that the brain naturally produces a THC-like substance that may perform some of the same functions that THC does. Such a substance subsequently was found and named anandamide, from the Sanskrit ānanda (“bliss”).
International trade in marijuana and hashish was first placed under controls during the International Opium Convention of 1925. By the late 1960s most countries had enforced restrictions on trafficking and using marijuana and hashish and had imposed generally severe penalties for their illegal possession, sale, or supply. Beginning in the 1970s, some countries and jurisdictions reduced the penalty for the possession of small quantities. The Netherlands is a notable example; the government there decided to tolerate the sale of small amounts of marijuana. Other European countries also began debating the decriminalization of so-called “soft drugs,” including marijuana.
In the United States, several states passed legislation in the late 1970s and early ’80s to fund research on or to legalize the medicinal use of marijuana, though some of these statutes were later repealed or lapsed. Renewed decriminalization efforts in the 1990s led to the legalization of medicinal marijuana in more than a dozen states, including Alaska, Arizona, California, Colorado, Nevada, Oregon, and Washington. In 2001, however, the U.S. Supreme Court ruled against the use of marijuana for medical purposes. Later that year Canada passed legislation easing restrictions on medicinal marijuana. That country’s new regulations included licensing marijuana growers to produce the drug for individuals with terminal illnesses or chronic diseases. In 2009 U.S. Attorney General Eric Holder issued a new set of guidelines for federal prosecutors in states where the medical use of marijuana was legalized. The policy shift mandated that federal resources were to be focused primarily on prosecuting illegal use and trafficking of marijuana, thereby rendering cases of medical use, in which those individuals in possession of the drug are clearly in compliance with state laws, less prone to excessive legal investigation. (For more information about the medical uses of marijuana, see medical cannabis.)
- The Editors of Encyclopaedia Britannica
While psychoactive drugs are typically categorized as stimulants, depressants, or hallucinogens, cannabis exhibits a mix of all of these effects. Scientific studies have suggested that other cannabinoids like CBD may also play a significant role in its psychoactive effects.
Dec 24, 2019 · Learn about the effects, uses, and risks of marijuana, a drug derived from the cannabis plant. Find out how marijuana affects the brain, body, and behavior, and what are the legal and medical issues surrounding it.
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Feb 6, 2021 · Cannabis is the name used to describe a family of flowering plants that come from the Cannabaceae family. There are several different species of cannabis, all of which contain more than 100 cannabinoids.
