Metformin for the management and prevention of antipsychotic-induced weight gain

Psychiatric disorders are commonly treated with antipsychotic medications; however, their use is frequently complicated by antipsychotic-associated weight gain (AAWG), which contributes to reduced treatment adherence and an increased cardiometabolic risk. Metformin, an insulin-sensitizing agent widely used in the management of diabetes, has emerged as a potential adjunctive therapy for mitigating AAWG, although real-world clinical data remain limited. The present prospective observational study evaluated the effectiveness of adjunctive metformin therapy in the management of AAWG in a routine psychiatric care setting. The present study was conducted over a period of 6 months and included 100 adult patients receiving antipsychotic treatment. Participants were allocated into two groups based on routine clinical practice: A test group receiving metformin in addition to antipsychotic therapy and lifestyle modifications (n=50), and a control group receiving antipsychotic therapy with lifestyle modifications alone (n=50). Changes in body weight and body mass index (BMI) were assessed as primary outcomes. The study population predominantly comprised younger adults aged 18-29 years, with a higher proportion of female patients. Olanzapine was the most frequently prescribed antipsychotic, and schizophrenia was the most common psychiatric diagnosis. The test group demonstrated a reduction in mean body weight and BMI over the study period, whereas the control group exhibited an increase in both parameters. Female patients reported a greater adherence to metformin therapy; however, adherence was assessed using self-reports and pill counts. These findings suggest that adjunctive metformin therapy may be associated with improvements in weight-related outcomes among patients receiving antipsychotics. Given the observational and non-randomized design, the results should be interpreted with caution, and further randomized controlled studies are warranted to confirm the long-term metabolic benefits.