Using data from a recent randomized clinical trial involving juvenile drug court (JDC), youth marijuana use trajectories and the predictors of treatment nonresponse were examined. Participants were 118 juvenile offenders meeting diagnostic criteria for substance use disorders assigned to JDC and their families. Urine drug screen results were gathered from weekly court visits for 6 months, and youth reported their marijuana use over 12 months. Semiparametric mixture modeling jointly estimated and classified trajectories of both marijuana use indices. Youth were classified into responder versus nonresponder trajectory groups based on both outcomes. Regression analyses examined pretreatment individual, family, and extrafamilial predictors of nonresponse. Results indicated that youth whose caregivers reported illegal drug use pretreatment were almost 10 times as likely to be classified into the nonresponder trajectory group. No other variable significantly distinguished drug use trajectory groups. Findings have implications for the design of interventions to improve JDC outcomes.
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