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根据下面资料，回答题 "Substance Abuse"--Severe Anxiety to Society
Technically, any substance other than food that alters our bodily or 31 functioning is a drug. Many people mistakenly believe the term drug refers only to some sort of medicine or an illegal chemical taken by drug addicts. They don' t realize that familiar substances such as alcohol and tobacco are also drugs. This is why the more neutral term substance is now used by many physicians and psychologists. The phrase "substance abuse" is often used 32 of "drug abuse" to make clear that substances such as alcohol and tobacco can be just as harmfully 33 as heroin and cocaine.
We live in a society in which the medicinal and social use of substances (drugs) is 34 : an aspirin to quiet a headache, some wine to be sociable, coffee to get going in the morning, a cigarette for the nerves. When do these socially acceptable and apparently constructive uses of a substance become misuses? First of all, most substances taken in 35 will produce negative effects such as poisoning or intense 36 distortions. Repeated use of substance can also lead to physical addiction or substance dependence. Dependence is marked first by an increased tolerance, with more and more of the substance required to produce the desired effect, and then by the appearance of unpleasant withdrawal symptoms when the substance is 37 .
Drugs (substances) that affect central nervous system and alter perception, mood, and behavior are known as psychoactive substances. Psychoactive substances are commonly grouped 38 to whether they are stimulants, depressants, or hallucinogen. Stimulants initially speed 39 or activate the central nervous system, 40 depressants slow it down. Hallucinogens have their primary effect on perception, distorting and altering it in a variety of ways including producing hallucinations. These are the substances often called psychedelic ( from the Greek word meaning "mind-manifesting" ) because they seemed to radically alter one' s state of consciousness.
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