Two waves of interviews have been completed that measure the youths' alcohol/other drug use, delinquency/crime, and mental health problems (physical and sexual abuse and emotional/psychological functioning). The measures include urine test results for drug use and recidivism measured to 3 1/2 years following their initial interviews. Initial interviews were completed with 399 youths, and follow-up interviews were completed with 305 youths (236 males and 69 females). The classification scheme reflects a profile of different detainee types having different degrees of risk for pursuing troubled behavior over time. Results are consistent with the growing body of literature that has found delinquent/criminal behavior to increase following involvement in illicit drug use and that shows arrests for drug offenses and property offenses decline with decreasing frequency of drug use. The youths in the study should be viewed in holistic terms, however. Their substance use and delinquency/crime are not only related to one another, but to a variety of mental health issues. Intervention programs should take these multiple needs into account. 10 tables and 65 references