['To ascertain the prevalence of psychiatric symptoms and substance use disorders among adolescents with a lifetime history of foster care placement, using data from a nationally representative sample of U.S. adolescents.', 'We studied adolescents aged 12-17 years in the public use file of the 2000 National Household on Drug Abuse (n = 19,430, including 464 adolescents with history of foster care placement). Psychiatric symptoms and substance use disorders were ascertained through direct interviewing of adolescents. Logistic regression analyses were used to estimate the odds of past-year psychiatric symptoms and substance use disorders among adolescents involved with foster care, as compared to those without a lifetime history of foster care placement (comparison group).', 'Adolescents involved with foster care had more past-year psychiatric symptoms, and especially more conduct symptoms, and past-year substance use disorders than those never placed in foster care. Adolescents involved with foster care were about four times more likely to have attempted suicide in the preceding 12 months (adjusted odds ratio [AOR] 3.95; 95% confidence interval [CI] 2.78, 5.61), and about five times more likely to receive a drug dependence diagnosis in the same period (AOR 4.81; 95% CI 3.22, 7.18).'] Do psychiatric symptoms and substance use disorders in a nationally representative sample of American adolescents involved with foster care?