BACKGROUND
Drug abusers are generally more involved in crime, in particular property crime, than people who are not drug abusers. Substitution programs have been developed in order to improve drug users’ quality of life and to decrease their criminal involvement. Several evaluations, but not all, have reported crime reductions following substitution therapies based on heroin and methadone prescription.

MAIN RESULTS
Heroin maintenance reduces crime significantly more than Methadone maintenance. Methadone maintenance reduces offending more than treatments without substitution therapy, but the mean effect size is not significant (p >.1). However, very large (and significant) reductions in criminal behaviour are observed during methadone maintenance therapy with respect to pre-treatment levels. Buprenorphine does not significantly reduce criminal behaviour, although effects are positive, be it with respect to methadone or a placebo. Naltrexone treatment reduces criminality significantly more than behaviour therapy or counselling.

CONCLUSION
Heroin maintenance has been found to significantly reduce criminal involvement among treated subjects, and it is more effective in crime reduction than methadone maintenance. Methadone maintenance greatly reduces criminal involvement, but apparently not significantly more so than other interventions. Buprenorphine and Naltrexone have been found to be promising, although few studies have been identified using these substances in maintenance treatment.