Humans have used drugs of various types since prehistoric times. Alcohol has been a common drug in the United States since the colonial period, and opium, marijuana, and heroin were common legal drugs in the late nineteenth century.
The distinction between legal and illegal drugs lacks a logical basis. Alcohol and tobacco kill many more people than all illegal drugs combined.
The use of several drugs is socially patterned. Males are more likely than females to use drugs, and religious people are less likely to use them than those who are less religious. The differences that race/ethnicity, education, and region of country make for drug use depends on the type of drug.
Biological theories assume that drug addiction results from a genetic predisposition, while psychological theories attribute drug use to certain personality traits and to positive reinforcement.
Sociological theories attribute drug use to peer and cultural influences. A sociological perspective suggests that the ultimate roots of drug use lie in the social environment rather than inside the individual.
Major approaches to dealing with drugs include treatment, prevention, harm reduction, and the use of the criminal justice system for illegal drugs. Critics of the war on drugs say that it does more harm than good, and they urge that serious consideration be given to decriminalizing marijuana and perhaps other drugs.