The NSDUH is an annual survey of the civilian, noninstitutionalized population of the United States aged 12 years old or older. An estimated 19.5 million Americans, or 8.3 percent of the population aged 12 or older, were current illicit drug users in 2002. Current drug use means use of an illicit drug during the month prior to the survey interview. Marijuana was the most commonly used drug. An estimated 2 million persons (0.9 percent) were cocaine users. An estimated 6.2 million persons (2.6 percent) were current users of psychotherapeutic drugs taken nonmedically. Approximately 1.9 million persons had used OxyContin nonmedically at least once in their lifetime. Among youths aged 12 to 17, 11.6 percent were current illicit drug users. An estimated 120 million Americans aged 12 or older reported being current drinkers of alcohol (51 percent). The prevalence of current alcohol use increased with increasing age. About one in seven persons drove under the influence of alcohol at least once in the 12 months prior to the interview. An estimated 71.5 million (30.4 percent) reported current use of a tobacco product. A higher proportion of males than females smoked cigarettes. The percentage of youths aged 12 to 17 that had ever used marijuana declined slightly from 21.9 to 20.6 percent in 2001-2002. Nonmedical pain reliever incidence increased in 1990, when there were 628,000 initiates, and in 2000, when there were 2.7 million. In 2001, the number was 2.4 million, not significantly different from 2000. The number of new daily cigarette smokers decreased from 2.1 million in 1998 to 1.4 million in 2001. The percentages of youths reporting that it was fairly or very easy to obtain specific drugs were 55 percent for marijuana, 25 percent for cocaine, 19.4 percent for LSD, and 15.8 percent for heroin. An estimated 22 million Americans were classified with substance dependence or abuse in 2002. The rate of substance dependence or abuse was highest among American Indians/Alaskan Natives. 1 table, 16 figures, 7 references, appendix