Results revealed a high prevalence of drug use due to the unique population studied. All but two of the heroin users were incarcerated youth. Drug use frequencies were highly associated with psychosocial variables such as sensation seeking, peer drug use, family drug use, susceptibility to peer pressure, perceived control to gain access to drugs, intention to try other substances, and perceived adverse consequences of drug use. Findings also revealed that females who used marijuana and females who occasionally used heroin were characterized by higher levels of sensation seeking and susceptibility to peer pressure than their male counterparts. Polydrug use was generally related to high levels of psychosocial vulnerability factors. The exclusive use of marijuana was associated with high susceptibility to peer pressure and with perceived control to gain access to drugs. Findings indicate a complex interplay of psychosocial variables and adolescent drug use, but they cannot be generalized beyond this sample. Figures, tables, and 55 references