Supplementary Material for: Short-Term Outcomes for Opiate and Crack Users Accessing Treatment: The Effects of Criminal Justice Referral and Crack Use

<b><i>Background/Aims:</i></b> The English drug treatment population doubled in size between 1998 and 2008, increasingly characterised by crack cocaine use and criminal justice system (CJS) referral. We assessed short-term (median 3.5 month) behaviour changes following participation in drug treatment and the moderating effect of CJS referral/crack use. <b><i>Methods:</i></b> Opiate and/or crack cocaine users (n = 1,267) were recruited from 342 agencies. Outcome effects were assessed via interaction term regression, clustered at participant level, controlling for client characteristics. Treatment retention effects were tested via Cox proportional hazard models. <b><i>Results:</i></b> Statistically significant improvements in health, drug use and offensive behaviour were observed (e.g. heroin use from 87 to 51%, acquisitive offending from 47 to 23%). Referral route was not associated with variation in outcomes. Crack use at baseline was associated with a greater chance of non-fatal overdose at follow-up (p = 0.035, 95% CI 1.08-8.20) but a greater reduction in offending income (p = 0.002, 95% CI £104-£419). <b><i>Conclusion:</i></b> Despite changes in the English drug treatment population, equivalent short-term improvements in client behaviour were observed a decade earlier. Outcomes for CJS-referred clients were comparable to non-CJS. Crack use at treatment entry offered some scope for greater improvements in offending but may be a barrier to cessation of mortality-associated risky behaviour.