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MARIJUANA Marijuana, mixture of leaves, stems, and
flowering tops of the Indian hemp plant Cannabis sativa, smoked or
eaten for its hallucinogenic and pleasure-giving effects. The psychoactive
ingredient of marijuana, tetrahydrocannabinol (THC), is concentrated in the
flowering tops; hashish, a drug prepared from the plant resin, has about
eight times more THC than marijuana. Marijuana grows throughout temperate
regions, with the more potent varieties produced in dry, hot, upland
climates. Except for limited medical purposes, cultivating marijuana is
illegal in all but a few countries. Known in Central Asia and
China as early as 3000 BC, marijuana was used as a folk medicine. About 1900
it started to be used as a pleasure-inducing drug, and by the 1960s and '70s
its use was widespread among students, becoming, after alcohol, the second
most popular drug. Although marijuana has not been proven to be physically
addicting, and no physical withdrawal symptoms occur when its use is
discontinued, psychological dependence does develop. Many users describe two
phases of marijuana intoxication: initial stimulation, giddiness, and euphoria,
followed by sedation and pleasant tranquility. Mood changes are often
accompanied by altered perceptions of time and space and of one's bodily
dimensions. The thinking processes become disrupted by fragmentary ideas and
memories. Many users report increased appetite, heightened sensory awareness,
and pleasure. Negative effects can include confusion, acute panic reactions,
anxiety attacks, fear, a sense of helplessness, and loss of self-control. Chronic marijuana users are said to develop an "amotivational syndrome" characterized by passivity, decreased motivation, and preoccupation with drug taking. The relationship of this syndrome to marijuana use, however, has not been established. Like alcohol intoxication, marijuana intoxication impairs reading comprehension, memory, speech, problem-solving ability, and reaction time. The effects on the intellect of long-term use are unknown. Consistent evidence that marijuana induces or causes brain damage does not exist. Medical research has indicated that the drug is effective in relieving some of the symptoms of glaucoma and in treating the nausea induced by cancer chemotherapy and radiation treatments. Also see: Marijuana Anonymous |
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