↵a Composite includes lifetime use of alcohol, marijuana, ≥1 more illicit drugs (can include cocaine, inhalants, heroin, methamphetamines, or ecstasy), and ever took prescription drugs without a doctor's prescription.
↵b Had sexual intercourse with ≥1 person during the 3 mo before the survey.
↵c Among students who were currently sexually active.
↵d Sample n is unweighted; percentage is weighted.
↵e Adjusted for sex, race/ethnicity, grade, and IDU.