Aims: Research has shown that treatment for opiate use reduces crime, however the extent to which this is maintained is open to question. The objective of this study was to measure the relationship between crime committal rates and ongoing benzodiazepine and cocaine use by clients in opiate drug treatment programs.

Methods: A national, prospective, longitudinal, multi-site drug treatment outcome study was conducted,404 participants were recruited from inpatient and outpatient settings and 97% were located at 3 years. Drug use and crimes committed were ascertained from the Maudsley Addiction Profile of Marsden et al. [Marsden, J., Gossop, M., Stewart, D., Best, D., Farrell, M., Lehmann, P., . . . Strang, J.(1998). The Maudsley Addiction Profile (MAP): A brief instrument for assessing treatment outcome. Addiction, 93, 1857–1867].

Findings: Analysis revealed that of those who had not committed an acquisitive crime at intake, those who used cocaine regularly at 1-year were 6.5 times more likely and those that used benzodiazepines regularly were eight times more likely to commit an acquisitive crime at 1-year. Of those who had committed an acquisitive crime at intake, those who used heroin regularly at 1-year were nine times more likely to commit acquisitive crime at 1-year than those who did not use heroin regularly at 1 year.

Conclusions: Treatment must place greater emphasis on reducing substitute drug use if opiate treatment is to effectively sustain crime reduction.