The main group of drugs that depress the central nervous system are the narcotics, such as codeine, heroin, meperidine, methadone, morphine, and paregoric. Other drugs in this category include alcohol, barbiturates, nicotine, tranquilizers, and some sleeping pills. Drugs that stimulate the central nervous system include cocaine and the amphetamines, such as Benzedrine, Dexedrine, and Methedrine. Drugs that produce hallucinations are known as hallucinogens, or psychedelics. Marijuana is classified as a mild hallucinogen, but it is much less powerful than other drugs in this category.
Depressants slow down the activities of the central nervous system.
If this system slows down too much, the body's vital functions may stop, which could be fatal. Dependence on depressants usually takes the form of both physical and psychological dependence. The narcotic depressants can cause dependence much more quickly than other depressants. The short-term effects of depressants include euphoria, relief of pain, and prevention of withdrawal symptoms. The long-term effects include depression, malnutrition, and constipation.