The effects of antipsychotic switching on diabetes in chronic schizophrenia

People with severe mental illness have a 20-year life-expectancy shortfall. The majority of antipsychotic medications are associated with obesity and heightened diabetes risk. People with severe mental illness less frequently achieve benchmarked diabetes care, often attributed to poor adherence, lower clinical attendance and documented medical biases in treatment. This case is presented to highlight the profound effect medication change can have on diabetes control.

A 56-year-old man with a 42-year history of schizophrenia had required clozapine treatment for the preceding 14 years. Type 2 diabetes and obesity occurred within 4 years of clozapine instigation. Glycaemic control had been continuously poor, despite frequent contact with diabetes services and multiple medications, including insulin at a dose exceeding 200 IU daily. Request for consideration of antipsychotic review and close interaction with the psychiatry team was initiated at the diabetes outpatient clinic. A gradual medication switch from clozapine to aripiprazole was associated with a reduction in HbA(1c) from 80 to 50 mmol/mol (9.5 to 6.7%) over 4 months, associated with a weight loss of 10 kg. Over the ensuing 2 years, the improvement in HbA(1c) has endured, with total weight loss of 13 kg and halving of insulin requirements.

This case illustrates the benefits of engagement between endocrinologists and psychiatrists to achieve the shared goal of improved physical health in severe mental illness. Greater interdisciplinary collaboration will help bridge the life-expectancy gap in severe mental illness and may assist in preventing disabling diabetes complications in this vulnerable patient group.