Psychosocial interventions for people with both severe mental illness and substance misuse.

BACKGROUND: Even low levels of substance misuse by people with a severe mental illness can have detrimental effects.

OBJECTIVES: To assess the effects of psychosocial interventions for substance reduction in people with a serious mental illness.

SEARCH STRATEGY: For this update (2007) we searched the Cochrane Schizophrenia Group Trials Register (May 2006) which is based on regular searches of major databases.

SELECTION CRITERIA: We included all randomised controlled trials (RCTs) comparing psychosocial interventions for substance misuse with standard care in people with serious mental illness.

DATA COLLECTION AND ANALYSIS: We extracted data independently. For dichotomous data we calculated relative risks (RR) and their 95% confidence intervals (CI) on an intention-to-treat basis, based on a random effects model. We calculated numbers needed to treat/harm (NNT/NNH) where data were homogeneous. For continuous data, we calculated weighted mean differences (WMD) again based on a random effects model.

MAIN RESULTS: Evaluation of long-term integrated care included 4 RCTs (total n=735). We found no significant difference on measures of substance use (n=85, 1 RCT, RR 0.89 CI 0.6 to 1.3) or loss to treatment (n=603, 3 RCTs, RR 1.09 CI 0.8 to 1.5). For the non-integrated intensive case management trials (4 RCTs, total n=151) we also found no significant difference for loss (n=134, 3 RCTs, RR 1.35 CI 0.8 to 2.2). Motivational interviewing plus cognitive behavioural therapy (3 RCTs, total n=276) did not reveal any advantage for retaining participants (n=36, 1 RCT, RR lost to treatment 0.50 CI 0.1 to 5.0) or for relapse (n=36, 1 RCT, RR 0.58 CI 0.3 to 1.1), and no benefit for reducing substance use (n=119, 1 RCT, RR 0.19 CI -0.2 to 0.6). Cognitive behavioural therapy alone (4 trials, total n=260) showed fewer participants lost from treatment (n=260, 4 RCTs, p=0.02, RR 0.61 CI 0.4 to 0.9). No benefits were observed on measures of lessening cannabis use (n=47, 1 RCT, RR 1.30 CI 0.8 to 2.2) or on the number of participants using substances (alcohol; n=46, 1 RCT, RR 5.88 CI 0.8 to 44.0, drugs; n=46, 1 RCT, RR 2.02 CI 0.9 to 4.8) and no differences were observed on measures of mental state (n=105, 1 RCT, RR 0.52 CI -0.8 to 1.8). We found no advantage for motivational interviewing alone (5 trials, total n=338) in reducing 'lost to evaluation' (n=338, 5 RCTs, RR 0.96 CI 0.6 to 1.5) compared with treatment as usual, although significantly more participants in the motivational interviewing group reported for their first aftercare appointment (n=93, 1 RCT, RR 0.69 CI 0.5 to 0.9, NNT 4 CI 3 to 12). Some differences were observed in abstaining from alcohol favouring treatment (n=28, 1 RCT, RR 0.36 CI 0.2 to 0.8, NNT 2 CI 2 to 5), but not other substances (n=89, 1 RCT, RR -0.07 CI -0.6 to 0.4) and no differences were observed in mental state (n=30, 1 RCT, WMD -4.20 CI -18.7 to 10.3). Finally, we found no significant differences for skills training in the numbers lost to treatment by 12 months (n=94, 2 RCTs, RR 0.70 CI 0.4 to 1.1).

AUTHORS' CONCLUSIONS: We included 25 RCTs and found no compelling evidence to support any one psychosocial treatment over another to reduce substance use (or improve mental state) by people with serious mental illnesses. Furthermore, methodological difficulties exist which hinder pooling and interpreting results; high drop out rates, varying fidelity of interventions, varying outcome measures, settings and samples and comparison groups may have received higher levels of treatment than standard care. Further studies are required which address these concerns and improve the evidence in this important area.