The study found that patterns of cocaine use changed little during adolescence and early adulthood for many of these justice-involved individuals. Their cocaine use was related to their involvement with deviant peers. Youth who reported high levels of cocaine use were more likely to have friends who used drugs and who had contact with the justice system compared with youths with lower levels of cocaine use. Further, the youths had family members who also had some degree of involvement with the justice system. These findings suggest that interventions designed to reduce cocaine use among many justice-involved youth should involve a multipronged focus on countering the influence of deviant peers and family members. Study data were obtained from a sample of 278 youth involved in the Youth Support Project (YSP), an innovative intervention program for youth involved in the justice system in Hillsborough County, FL. The youth completed at least one of three followup interviews. Interviews addressed family-member alcohol abuse, other drug abuse, mental health problems, and criminal behavior. Interviews also focused on friends' substance use and involvement with the criminal justice system. 5 tables, 3 figures, 64 references, and appended results of factor analyses of the family and friends questions as well as a description of the hair testing of the youth for drug use