This 1982 national survey on drug abuse is the seventh in a series of surveys since 1971 sponsored by the National Institute on Drug Abuse. To investigate the current prevalence of drug abuse in a nationwide sample, 5,624 randomly selected Americans (aged 12 and older) were personally interviewed in their homes using a specially designed answer sheet to assure privacy. An analysis of the results showed a reversal of the upward trends in drug abuse charted in surveys through the 1970's. The use of marijuana among youths (12-17) and young adults (18-25) has leveled off and has significantly declined in the percentage of persons who currently use marijuana, alcohol, narcotics, and tobacco. In the older adult population (26 and older), lifetime use of marijuana and narcotics increased between 1979 and 1982 and current use did not decrease; this trend reflects the fact that drug users in the early 1970s have now moved into a different demographic group. Older adults continued to show a decline in the use of tobacco. Persons who have tried hallucinogens, cocaine or heroin are a subset of those who have tried marijuana. Levels of drug use opportunity remained high with a majority of adolescents and young adults and 41 percent of persons aged 26 and older reporting the availability of the drug if they desired to use it. Similarly, a majority of young adults reported the availability of cocaine. (Numerous tables present the data. The survey questionnaire is appended.) (BL)