Interventions for drug-using offenders with co-occurring mental illness

This is an updated version of an original Cochrane review published in Issue 3 2006 (Perry 2006). The review represents one from a family of four reviews focusing on interventions for drug-using offenders. This specific review considers interventions aimed at reducing drug use or criminal activity, or both for drug-using offenders with co-occurring mental illness.

To assess the effectiveness of interventions for drug-using offenders with co-occurring mental illness in reducing criminal activity or drug use, or both.

We searched 14 electronic bibliographic databases (searched between 2004 and 21 March 2013) and five internet resources (searched between 2004 and 11 November 2009). We contacted experts in the field for further information.

We included randomised controlled trials designed to reduce, eliminate or prevent relapse in drug-using offenders with co-occurring mental illness. We also reported data on the cost and cost effectiveness of interventions.

We used standard methodological procedures expected by The Cochrane Collaboration.

We identified 76 trials across the four reviews. Following a process of pre-screening, we judged eight trials to meet the inclusion criteria for this specific review (three of the five trials are awaiting classification). The five included 1502 participants. The interventions reported on case management via a mental health drugs court, a therapeutic community, and an evaluation of a motivational interviewing technique and cognitive skills in comparison to relaxation training. The methodological quality of the trials was generally difficult to rate due to a lack of clear reporting. On most risk of bias items, we rated the majority of studies as unclear. Overall, the combined interventions did not show a statistically significant reduction in self reported drug use (2 studies, 715 participants; risk ratio (RR) 0.82, 95% confidence interval (CI) 0.44 to 1.55). A statistically significantly reduction was shown for re-incarceration (4 studies, 627 participants; RR 0.40, 95% CI 0.24 to 0.67 and mean difference (MD) 28.72, 95% CI 5.89 to 51.54) but not re-arrest (2 studies, 518 participants; RR 1.00, 95% CI 0.90 to 1.12). A specific subgroup analysis combining studies using therapeutic community interventions showed a statistically significant reduction in re-incarceration (2 studies, 266 participants; RR 0.29, 95% CI 0.16 to 0.54) but not re-arrest (1 study, 428 participants; RR 0.90, 95% CI 0.61 to 1.33). Case management via a mental health court and motivational interviewing with cognitive skills did not show a statistically significant reduction in criminal activity (1 study, 235 participants; RR 1.05, 95% CI 0.90 to 1.22) or self reported drug misuse (1 study, 162 participants; MD -7.42, 95% CI -20.12 to 5.28). Due to the small number of studies, we were unable to analyse the impact of setting on outcome. Some cost information was provided in the trials but not sufficient to be able to evaluate the cost effectiveness of the interventions.

This review highlights the paucity of evidence for drug misusing offenders with co-occurring mental health problems. Two of the five trials showed some promising results for the use of therapeutic communities and aftercare, but only in relation to reducing subsequent re-incarceration. The studies overall, showed a high degree of statistical variation demonstrating a degree of caution in the interpretation of the magnitude of effect and direction of benefit for treatment outcomes. More evaluations are required to assess the effectiveness of interventions for drug-using offenders with co-occurring mental health problems.