Effectiveness of a brief motivation enhancing intervention on treatment initiation, treatment retention and abstinence: Results from a multi-site cluster-randomized trial

Abstract The aim of this study was to test the effectiveness of a brief motivational enhancing intervention (MEI) as an add-on to supervision-as-usual (SAU) in reducing time to treatment initiation in offenders with substance use disorders (SUDs) under probation supervision. We also tested the effectiveness in enhancing treatment retention and abstinence of primary substance rates. The study was designed as a multi-site, cluster randomized trial (CRT) in six addiction probation offices. We randomized 73 probation officers (37 to intervention, 36 to control) and followed 220 substance-abusing repeat offenders during their supervision (111 intervention, 109 control). Individualized SAU was compared with supervision with MEI. We report time to treatment initiation, treatment retention rate during the 12 months follow-up, and primary substance abstinence rate in the 30 days before follow-up. Results show that time to treatment initiation (χ2(1) = 1.817, p = .178), and the proportion of treatment retention (OR = 1.980, p = .213) and primary substance abstinence (OR = 0.945, p = .886) did not significantly differ between offenders that received SAU plus MEI and those that received SAU at 12 months follow-up. Our findings provide no evidence that supervision plus a brief manual-base MEI is more effective than SAU.