Although most people use prescription medications responsibly, the nonmedical use of prescription drugs is a serious public health concern in the United States. According to the 2000 National Household Survey on Drug Abuse, an estimated 14 million Americans were current illicit drug users—6.3% of the population 12 years old and older. Although marijuana was the most commonly used illicit drug (used by 76% of current illicit drug users), about 41% of current illicit drug users in 2000 (an estimated 5.7 million Americans) used illicit drugs other than, or in addition to, marijuana and hashish.

Of the 5.7 million users of illicit drugs other than marijuana, 3.8 million used psychotherapeutic drugs nonmedically. Psychotherapeutics include pain relievers (2.8 million users), tranquilizers (1 million users), stimulants (0.8 million users), and sedatives (0.2 million users).