Concurrent disorder refers to a diverse set of combinations of substance use disorders and mental disorders simultaneously in need of treatment. Concurrent disorders are underdiagnosed, undertreated, and more complex to manage, practicing the best recommendations can support better outcomes. The purpose of this work is to systematically assess the quality of the current concurrent disorders’ clinical recommendation management guidelines. Literature searches were performed by two independent authors in electronic databases, web, and gray literature. The inclusion criteria were English language clinical management guidelines for adult concurrent disorders between 2000 and 2020. The initial search resulted in 8841 hits. A total of 24 guidelines were identified and assessed with the standardized guidelines assessment tool: AGREE II (Appraisal of Guidelines for Research and Evaluation). Most guidelines had acceptable standards, however, only the NICE guidelines had all detailed information on all AGREE II Domains. Guidelines generally supported combinations of treatments for individual disorders with a very small evidence base for concurrent disorders, and they provided little recommendation for further structuring of the field, such as level of complexity or staging, or evaluating different models of treatment integration.

The high prevalence of HCV among individuals who were homeless with mental illness underlies the importance of prevention and treatment of HCV in this population, especially those with concurrent substance use disorders. Self-report seems to be a valid tool for evaluation of the HCV status in this population.

Aim: HCV treatment in people who actively inject drugs (PWID) (active PWID) is sometimes withheld. We propose that active PWID can be treated for HCV in the right setting. Methods: HCV-infected active PWID were evaluated at a multidisciplinary clinic in an observational study. The primary end point was a sustained virologic response following HCV therapy. Results: We included 40 active PWID, of which 63% used heroin, 70% used cocaine and 37% received all-oral regimens. With a mean follow-up of 570 days, 78% subjects achieved sustained virologic response (93% on all-oral regimens; p < 0.05), with no recurrent viremia. Conclusion: Active PWID can be effectively treated for HCV, especially with all-oral regimens and rates of recurrent viremia can be reduced in a multidisciplinary healthcare setting.