Adjunctive Metformin May Improve Weight Outcomes in Patients on Antipsychotics: Study
Researchers have found in a new study that adjunctive metformin may help improve weight-related outcomes in patients receiving antipsychotic therapy, though findings from observational data should be interpreted cautiously and require confirmation through randomized controlled trials.
Antipsychotic-associated weight gain (AAWG) remains a debilitating side effect that elevates cardiometabolic risks, yet despite evidence from controlled trials, a significant gap exists in real-world clinical data from diverse settings, particularly regarding routine prescribing practices. To address this, Professor Sara Shreen of the Deccan School of Pharmacy and her team aimed to evaluate the effectiveness of adjunctive metformin therapy in managing these weight-related complications within routine psychiatric care.
Therefore, the six-month, prospective observational study followed 100 adult patients between the ages of 18 and 65 at a hospital in Hyderabad, comparing 50 individuals receiving metformin doses of 500 mg, 850 mg, or 1 g alongside lifestyle modifications against a control group of 50 receiving only lifestyle guidance. Utilizing t-tests and analysis of variance, the researchers evaluated primary endpoints of body weight and body mass index (BMI) changes while excluding those outside the specified age range to ensure a focused clinical assessment.
Key Clinical Findings of the Study Include:
Clinically Meaningful Weight Reduction: The investigation revealed that the metformin cohort achieved a net weight reduction of approximately 2.47 kg, whereas the control group experienced a weight gain of 2.70 kg.
Significant BMI Improvement: The research demonstrated a significant decrease in BMI of 1.0 kg/m² for those on adjunctive therapy, contrasting with a 1.1 kg/m² increase in the lifestyle-only group.
Enhanced Medication Adherence: The analysis highlighted that female participants exhibited greater consistency in following the metformin regimen, although weight outcomes remained similar across genders.
Favorable Tolerability Profile: The study indicated that adverse drug reactions were not significantly associated with weight fluctuations, suggesting the intervention is generally well-tolerated.
Proactive Management Benefit: The study emphasizes that initiating such therapy early may prevent the establishment of a higher weight set point that is often difficult to reverse later.
The results suggest that adjunctive metformin is an effective tool for weight stabilization, as the test group's mean weight dropped from 60.45 kg to 57.98 kg over the six-month period while the control group's weight rose from 58.24 kg to 60.94 kg.
These outcomes indicate that clinicians could consider integrating metformin early in the treatment course for patients at high risk of weight gain to improve their long‑term physical health and medication compliance.
Although the single-center, non-randomized nature of the study and its six-month timeframe are acknowledged limitations, these findings highlight the necessity for future large-scale randomized trials to confirm the enduring metabolic benefits and explore gender-specific adherence behaviors.
Reference
Shreen S, Ali M, Eram SL, Baig M, Nayeem MA, Omer WFA, Nasirabadi MZ, Hussain SA. Metformin for the management and prevention of antipsychotic-induced weight gain. Medicine International. 2026;6(3):312.
