The sample youth entered a service delivery project funded by the National Institute on Drug Abuse called the Youth Support Project. Self-reported data were collected during confidential, in-depth, baseline interviews lasting an average of 2 hours. The hypothesized model was supported by overall data and for male youth; data for female youth suggested they used alcohol and marijuana for different reasons. The authors emphasize the importance of prevention and early intervention efforts involving at risk youth and their families to reduce the prevalence and adverse consequences of traumatic experiences. 39 references and 2 figures