The proposed research will determine the effects of past and current sexual and physical abuse on client engagement in drug treatment and treatment effectiveness. It will test the Abuse-Distress (A-D) theoretical model that predicts lower levels of treatment engagement and a higher risk of relapse for those with histories of sexual and physical abuse. The findings will add to the evidentiary record concerning the effects of potentially traumatic experiences and comorbidity on treatment participation, retention and outcomes. Moreover, it will empirically explore the utility of the A-D model for males and females, ethnic populations, and those with different abuse and treatment histories. Finally, it will identify client characteristics that are important predictors of treatment engagement and relapse and that are potentially amenable to clinical intervention. The analyses will utilize data from five recently completed and ongoing treatment evaluations that """"""""piggy-back"""""""" basic science questions with the evaluation concerns. The evaluations involve retrospective/prospective longitudinal designs soliciting pre-treatment, in-treatment, and post-treatment client information on more than 1000 male and female subjects with differing ethnic and racial backgrounds. All five studies include standardized measures of sexual and physical abuse along with frequently used measures and standardized scales assessing the A-D and other predictor variables. Along with OLS and logistic regressions, repeated measures, discriminant analysis, and other multivariate statistical applications, structural equations modeling (EQS) will be utilized to measure the interrelationship between the A-D predictor variables and treatment engagement and relapse risk.