Long-Acting Injectable Antipsychotics in Schizophrenia and Comorbid Substance Use Disorder: A Systematic Review of the Literature.

Background/Objectives: The aim of this systematic review is to assess the efficacy, effectiveness, and safety of LAI antipsychotics in patients with schizophrenia and comorbid SUD, providing useful information for clinical decision making and guiding future research in the management of this complex patient population. Methods: The search was conducted on 1 July 2026 and produced 87 results in total; after the screening process, 78 articles were excluded based on the predefined eligibility criteria. The full texts of the remaining 9 studies were retrieved and thoroughly evaluated for inclusion in the qualitative synthesis. Results: The 9 articles that met the criteria for inclusion included 2062 patients in total with follow-up periods varying between 6 months and 3 years. Several studies reported favorable clinical outcomes associated with LAIs; however, not all studies demonstrated clear superiority of LAIs over oral antipsychotics. Conclusions: The present review suggests that LAIs may represent a valuable therapeutic strategy for patients with schizophrenia and comorbid SUD, although the available evidence remains heterogeneous in terms of study design, patient populations, and outcome measures.