Methamphetamine, which increases physical activity and suppresses the appetite, is of limited usefulness in the treatment of attention deficit disorder, narcolepsy, and obesity. However, heavy or prolonged use (drug abuse) may produce powerful side effects, including aggression and paranoia, kidney and lung disorders, brain and liver damage, chronic depression, immune deficiency disorders, convulsions, and schizophrenia. It is normally taken in pill form or, as a crystalline powder (“crystal meth”), sniffed through a hollow tube; it may also be taken intravenously.

Methamphetamine was viewed with deep suspicion and hostility in the United States by the 1960s, not only by law-enforcement officials, politicians, the media, and medical professionals but also by large sections of the drug subculture. After the Controlled Substances Act (1970) severely restricted its availability, a large illicit manufacturing industry, relying on hundreds of clandestine “meth labs,” arose in the Southwest and West and spread to parts of the Midwest in the 1990s. Despite periodic police crackdowns, large quantities of the drug continue to be produced in these labs.

Methamphetamine use has been particularly widespread in Pacific Rim nations, where it has become a serious social problem. Partly because of its association with energy and aggression, its growing use was often correlated with rapid modernization and industrialization. Although reliable figures were very hard to find, some studies suggested that a substantial increase in usage did not occur in the 1990s. Nevertheless, in the United States a survey in the mid-1990s claimed that nearly five million people had tried methamphetamine, representing an increase of approximately 240 percent from 1990.