Aims: This review provides evidence of which interventions need to be part of effective outpatient integrated treatment for patients with comorbid schizophrenia and substance use disorders. Methods: A total of 14 randomized controlled trials were included. Effect sizes are provided to assess the magnitude of the treatments' efficacy. Results: Despite the studies' heterogeneity, we can conclude that certain programs (e.g. Behavioral Treatment for Substance Abuse in Severe and Persistent Mental Illness ) and specific interventions (e.g. motivational interviewing, family interventions) seem to be effective. Moreover, programs integrating multiple interventions are more likely to be positively related to better outcomes than single interventions. Finally, the lack of difference between effect sizes of assertive community treatment compared to case management suggests that a lower caseload is not necessary for positive treatment outcomes. Conclusion: Integrated treatment seems advantageous, although effect sizes are mostly modest. More homogeneous and qualitative sound studies are needed.