IntroductionThis review aims to synthesise the literature on the efficacy, evolution, and challenges of implementing Clincian Decision Support Systems (CDSS) in the realm of mental health, addiction, and concurrent disorders.MethodsFollowing PRISMA guidelines, a systematic review and meta‐analysis were performed. Searches conducted in databases such as MEDLINE, Embase, CINAHL, PsycINFO, and Web of Science through 25 May 2023, yielded 27,344 records. After necessary exclusions, 69 records were allocated for detailed synthesis. In the examination of patient outcomes with a focus on metrics such as therapeutic efficacy, patient satisfaction, and treatment acceptance, meta‐analytic techniques were employed to synthesise data from randomised controlled trials.ResultsA total of 69 studies were included, revealing a shift from knowledge‐based models pre‐2017 to a rise in data‐driven models post‐2017. The majority of models were found to be in Stage 2 or 4 of maturity. The meta‐analysis showed an effect size of −0.11 for addiction‐related outcomes and a stronger effect size of −0.50 for patient satisfaction and acceptance of CDSS.DiscussionThe results indicate a shift from knowledge‐based to data‐driven CDSS approaches, aligned with advances in machine learning and big data. Although the immediate impact on addiction outcomes is modest, higher patient satisfaction suggests promise for wider CDSS use. Identified challenges include alert fatigue and opaque AI models.ConclusionCDSS shows promise in mental health and addiction treatment but requires a nuanced approach for effective and ethical implementation. The results emphasise the need for continued research to ensure optimised and equitable use in healthcare settings.