When examined separately, rates were generally higher in the high-risk sample than the normative control group; for example across the demographic groups, 58–75 % reported very early initiation of tobacco use (compared to 39–63 % in the normative sample), 46–62 % reported the very early initiation of alcohol or drug use (compared to 32–49 % in the normative sample), and 18—54 % reported the very early initiation of sexual activity (compared to 2–31 % in the normative sample.) Consistent with prior research, these findings show that children with early-starting conduct problems are at elevated risk for the precocious initiation of illicit substance use and sexual activities. Unprotected sexual activity was common, with one-third of the girls in the high-risk sample reporting a pregnancy and one-fifth reporting an STD by eleventh grade (age 17 for most). Correlations among risk behaviors are shown in Table 2. As anticipated, the timing of first sexual intercourse was correlated with the timing of first tobacco and alcohol/drug use.
