• Posted October 31, 2023

Metformin May Help Young Patients With Bipolar Disorder Avoid Weight Gain

Taking the drug metformin -- typically used for type 2 diabetes -- can help counter weight gain in young people who are taking medication for bipolar disorder, according to a new trial.

While second-generation antipsychotic medications (SGAs) that treat bipolar disorder can help improve mental health, significant side effects include higher blood pressure and blood sugar, increased appetite and weight gain.

"We, the clinicians, naively justified that we're improving your psychosis, so just deal with the weight gain,"said trial co-leader Dr. Victor Fornari, a child/adolescent psychiatrist at Northwell Health in Glen Oaks, N.Y. "But patients stopped taking their medicine because they said they didn't want to gain weight."

A survey showed patients wanted interventions to reduce these side effects, according to Christina Klein, a University of Cincinnati research scientist.

The study had broad enrollment criteria and was conducted at a wide variety of clinics, she said. It included more than 1,500 patients ages 8 to 19 who had bipolar disorder and were taking SGAs.

"It was a large sample of patients to really demonstrate what's going on,"Fornari said in a University of Cincinnati news release. "I don't know that anybody has done a study of this magnitude."

Trial participants received recommendations for healthy eating and exercise. Half were also prescribed metformin.

"If patients weren't doing well on the metformin, they could come off and stay in this study,"Klein said in the release. "Really we're just trying to meet the patients when and where they received services, seeing what happens to them over the course of two years."

In a survey prior to the interventions, 87% of youth reported taking their bipolar medication regularly, but most were unhappy with their weight.

The research team also collected data to determine if young people had metabolic syndrome, a risk for diabetes and heart disease that is a common consequence of taking SGAs. At the outset, about 33% had metabolic syndrome.

"The key elements of metabolic syndrome are obesity, high blood pressure, elevated triglycerides and elevated glucose,"said Dr. Claudine Higdon, a child/adolescent psychiatrist at Northwell Health. "It is important that clinicians monitor for metabolic syndrome when treating youth with second-generation antipsychotics."

Six-month follow-up data showed that metformin had a modest but significant effect in preventing and, in some cases, reversing weight gain. It was safe, with some gastrointestinal symptoms as the only side effect.

"It's not a drug you take and weight falls off of you, but it tends to reduce that out-of-control appetite, which we think then makes it easier for patients to adhere to a healthy diet and as they lose some weight maybe also make it easier for them to engage in more exercise,"said Jeffrey Welge, a professor of psychiatry, behavioral neuroscience and environmental and public health at the University of Cincinnati.

"So, the lifestyle is really what's driving good outcomes, but metformin is in some cases putting the wind at their back to help with that," Welge said in the release.

Taking metformin did not have a significant effect on metabolic syndrome in the short term. More research is needed on that, researchers said.

"It's safe, effective and very inexpensive. It's an intervention that has the potential to have widespread applicability,"Fornari said. "It's not a medicine that you need to have an endocrinologist or a pediatrician prescribe, and I think it really speaks to the fact that the psychiatrist needs to be caring for the entire person, the physical and the mental health of the patient."

Study findings were published in the October issue of Journal of the American Academy of Child & Adolescent Psychiatry and presented Friday at a meeting of the American Academy of Child and Adolescent Psychiatry in New York City.

More information

The U.S. National Institute of Mental Health has more on bipolar disorder.

SOURCE: University of Cincinnati, news release, Oct. 27, 2023