Abstract
The prevalences of methamphetamine and organic solvent abuses are most serious social problems concerning drug abuse in Japan, and such prevalences tend to progressively extend in spite of a strong legal regulation. The drug abuses are not only problems connected with gangstar and juvenile delinquent groups, but also based on a common mechanism to our daily habits, such as drinking alcohol and tea, and smoking cigaretts, i.e., self-administraion of dependence-producing drugs. All of the dependence-producing drugs usually show psychotropic effects, and the effects frequently elicit an euphoria, which becomes a reinforcing effect of drug-taking behavior. The problems of drug abuse/dependence are not only drug-taking behavior itself, but also the psychotoxic effects of these drugs. Amphetamines, cocaine, organic solvents etc. show a strong psychotoxic effect, and easily elicit paranoid-hallucinative schizophrenia-like symptoms. The effect is enhanced by repeated administration of these drugs, i.e., development of reverse tolerance. The reverse tolerance to the psychotoxic effect once produced persists for a long period, and frequently causes the acute exacerbation of schizophrenia-like symptoms. The development of tolerance to the euphorogenic effect of drugs results in an increase in the dose, frequency and number of the drug abuse, and simultaneously accelerates development of reverse tolerance to the psychotoxic effect. In this review, we will discuss drug-abuse problems from the social and pharmacological viewpoints.
