Metformin Beneficial for Managing Weight in Youth With Bipolar Spectrum Disorder

FRIDAY, Nov. 21, 2025 (HealthDay News) — The benefits of metformin outweigh the risks for young people with bipolar spectrum disorder who have overweight or obesity and are treated with second-generation antipsychotics, according to a study published in the December issue of The Lancet Psychiatry.

Melissa P. DelBello, M.D., from the University of Cincinnati College of Medicine, and colleagues examined the effect of metformin treatment in young people treated with second-generation antipsychotics who had a bipolar spectrum disorder with overweight or obesity. Youth with overweight or obesity aged 8 to 19 years were enrolled and randomly assigned to the healthy eating and physical activity (LIFE) or the metformin plus LIFE (MET plus LIFE) interventions (788 and 777, respectively).

The researchers found that after six and 24 months, assignment to the MET plus LIFE versus LIFE intervention resulted in a greater change in body mass index z-score (standardized effect size, 0.26 and 0.11 at months 6 and 24, respectively). Twelve and one participants taking metformin attempted suicide once and twice, respectively, compared with 25 and three, respectively, among those not taking metformin. The proportion of patients with any suicidality during randomized treatment did not differ significantly (8 versus 9 percent in MET plus LIFE and LIFE, respectively). In the MET plus LIFE group, gastrointestinal adverse events were two to four times more common.

“The interpretation for this is that the effect on weight is modest, but for most patients the benefits of metformin outweigh the risks,” coauthor Christina C. Klein, Ph.D., also from the University of Cincinnati College of Medicine, said in a statement.

Several authors disclosed ties to the biopharmaceutical industry.

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