Objective: The recognition of concurrent disorders (combined mental health and substance use disorders) has increased substantially over the last three decades, leading to greater numbers of people with these diagnoses and a subsequent greater financial burden on the health care system, yet establishing effective modes of management remains a challenge. Further, there is little evidence on which to base recommendations for a particular mode of health service delivery. This paper will further summarize the existing treatment models for a comprehensive overview. The objectives of this study are to determine whether existing service models are effective in treating combined mental health and substance use disorders and to examine whether an integrated model of service delivery should be recommended to policy makers. The following two research questions are the focus of this paper: (1) Are the existing service models effective at treating mental health and substance use disorders? (2) How are existing service models effective at treating mental health and substance use disorders? Methods: We used various databases to systematically review the effectiveness of service delivery models to treat concurrent disorders. Models were considered effective if they are found to be cost-effective and significantly improve clinical and social outcomes. Results: This systematic review revealed that integrated models of care are more effective than conventional, nonintegrated models. Integrated models demonstrated superiority to standard care models through reductions in substance use disorders and improvement of mental health in patients who had diagnoses of concurrent disorders. Our meta-analysis revealed similar findings, indicating that the integrated model is more cost-effective than standard care. Conclusions: Given the limited number of studies in relation to service delivery for concurrent disorders, it is too early to make a strong evidence-based recommendation to policy makers and service providers as to the superiority of one approach over the others. However, the available evidence suggests that integrated care models for concurrent disorders are the most effective models for patient care. More research is needed, especially around the translation of research findings to policy development and, vice versa, around the translation from the policy level to the patients' level.
Keywords: Concurrent disorders service delivery; concurrent disorders treatment; cost effectiveness; integrated treatment.