Addressing Metabolic Comorbidity in Individuals With Intellectual and Developmental Disability on Antipsychotics

Individuals with intellectual and developmental disabilities (IDDs) are at increased risk for serious metabolic comorbidities, which is further exacerbated by the high rate of antipsychotic use in this population. There is currently a lack of literature on effective treatment options for antipsychotic-induced weight gain and metabolic abnormalities in IDD. This case series reports on the clinical use of metformin in patients with IDD on antipsychotics.We conducted a retrospective review of patients in a novel clinical service at the Centre for Addiction and Mental Health in Toronto, Ontario, Canada for adults with IDD experiencing antipsychotic-related weight gain and other metabolic aberrations. Charts were reviewed for weight and other metabolic outcome measures before and after commencing metformin treatment.In 11 patients referred to this clinic, the mean weight loss while on metformin treatment was 11.1 kg, with over 50% of the sample achieving clinically meaningful weight loss of7%. Additional adaptive changes were observed for fasting glucose, glycated hemoglobin, triglyceride, and high-density lipoprotein cholesterol levels.In line with its use in severe mental illness, metformin may be a safe, effective, and accessible treatment option for patients with IDD experiencing metabolic adverse effects of antipsychotic medication. Further research and randomized controlled trials are needed to examine the efficacy of metformin in this population.