Metformin for Antipsychotic-induced Weight Gain in Adults With Intellectual Disability

This study is testing whether metformin — a widely used and safe diabetes medication — can help prevent or reverse weight gain caused by antipsychotic medications in people with intellectual and developmental disabilities (IDD). Antipsychotic medications are commonly prescribed to manage challenging behaviors in people with IDD, but they often cause significant weight gain, which in turn raises the risk of diabetes, heart disease, and other serious health problems. Metformin is known to counter antipsychotic-related weight gain in the general population, but this hasn't been well studied in people with IDD. Eligible participants must be 16 to 65 years old with an IDD diagnosis, be on a stable antipsychotic regimen for at least 3 months, and have obesity or overweight with related health complications. Women of childbearing age must use appropriate contraception. People with diabetes, metabolic acidosis, serious kidney or liver disease, or a history of unsuccessful metformin treatment are excluded. This research is critically important because people with IDD are among the most vulnerable to medication side effects and the least represented in clinical research. They experience high rates of antipsychotic prescribing and disproportionate rates of obesity-related illness. An effective, accessible, and affordable solution like metformin could dramatically reduce the cardiometabolic burden on this population and improve their long-term health outcomes.