CONCLUSION: Although several RCTs were identified, substantial clinical and methodological heterogeneity was evident among the studies (e.g., patients with multiple disorders, and multi-faceted interventions). Smaller systematic reviews focused on specific interventions (e.g., behavioural therapies) and concurrent disorders (e.g., depression and substance use) may be warranted. Due to considerable heterogeneity, more RCTs are needed before conducting larger systematic reviews or meta-analyses.
