The survey examined trends in the prevalence of illicit drug, alcohol, and tobacco use between 1976 and 1993, explored demographic correlates of drug use, obtained information about drug use patterns and problems, and investigated drug use in six Standard Metropolitan Statistical Areas. In 1993, an estimated 12 million individuals were current illicit drug users, compared to 11 million in 1992, 13 million in 1991, and 22 million in 1985. About 9 million people were current marijuana users, 103 million were current drinkers, and 50 million were current smokers in 1993. Marijuana remained the most popular illicit drug in 1993. Overall cocaine use did not change between 1992 and 1993, but the number and proportion of past-year and current cocaine users decreased substantially since their peak years in the late 1970's and early 1980's. Inhalant, hallucinogen, and heroin use remained roughly stable between 1992 and 1993, with fewer than 0.5 percent reporting current use of each drug. Nonmedical use of psychotherapeutic drugs did not change between 1992 and 1993, and such use continued to be highest among males, whites, and the unemployed. Alcohol continued to be the most widely used psychoactive drug in the surveyed population, with 103 million current drinkers and 11 million current heavy drinkers. Cigarette smoking declined for women from 25 percent in 1992 to 22 percent in 1993, although cigarette smoking did not significantly change for men. During 1993, 489,000 cocaine users, 594,000 marijuana users, 4.6 million alcohol drinkers, and 915,000 cigarette smokers reported three or more problems associated with each respective substance. The use of alcohol alone remained the most common drug use pattern. The six metropolitan areas sampled as part of the survey (Chicago, Denver, Los Angeles, Miami, New York, and the District of Columbia) varied in their prevalence of licit and illicit drug use. Denver residents reported the highest and Miami residents the lowest prevalence of lifetime illicit drug use. Appendixes contain NHSDA definitions for survey years 1972-1993, information on the survey methodology, and drug answer sheets from the survey questionnaire. Footnotes, tables, and figures