Most US adolescents (60.2%) reported having had the opportunity to use illicit drugs (Table 2). This exposure concerned 39.2% of adolescents aged 13 to 14 years and 81.4% of adolescents aged 17 to 18 years, thereby doubling during the adolescent period. The use of illicit drugs for these same cohorts ranged from 9.6% (nearly a quarter of exposed youth aged 13–14 years) to 42.5% of the oldest adolescents (52.2% of those exposed), respectively. Abuse of illicit drugs was slightly more common than the abuse of alcohol, ranging from 3.4% of youth in the 13- to 14-year cohort to 16.4% of adolescents aged 17 to 18 years old. Figure 2 presents the cumulative prevalence of drug use stages by age. The median ages of onset for each category were 13 years for the first opportunity to use illicit drugs, 14 years for the first illicit drug use, 14 years for drug abuse with dependence, and 15 years for drug abuse without dependence. Similar to the pattern in alcohol use, there was a slight overall male preponderance in prevalence of stages of
