• Positive pressure reduces drug use among justice-involved youths when negative pressures are employed sparingly.
• Negative pressures are associated with increased drug use among justice-involved youths
• Parental involvement in probation reduces drug use among females but is a marker of increased risk for drug use among males.
• Higher levels of treatment involvement early in the course of probation reduces drug use later in probation.
Use of drugs and alcohol by justice-involved youths is a longstanding concern for juvenile justice policy-makers and researchers. However, little explored in this research is how the tactics and strategies employed by probation officers with this population impacts drug use outcomes. This study explored the effects of four types of probation strategies (positive pressure, negative pressure, parental involvement, treatment referrals) on 12-month drug use trajectories in a sample of 144 youths under probation supervision. Multilevel negative binomial regression models found that positive pressures (incentives & rewards) reduced drug use when negative pressures (threats & confrontation) were minimized. More frequent parental involvement early in the course of probation was associated with reduced drug use for girls, and was associated with increased drug use for both boys and girls later during the probation period. Finally, early referral to drug treatment programs was associated with reduced drug use outcomes. These findings suggest practical program and policy strategies to reduce drug use among probation-involved youths.