Drug cuts weight gain in autistic kids who take antipsychotics

By Louise Kinross

Weight gain is a dangerous side effect of antipsychotics used to treat severe irritability and aggression in some children with autism.

Now a randomized study published in JAMA Psychiatry finds that taking the diabetes drug metformin while on atypical antipsychotics decreases this weight gain. The study was led by Holland Bloorview researchers in partnership with scientists at Ohio State University, the University of Pittsburgh, Columbia University and Vanderbilt University.

In the four-month study of 60 kids with autism aged six to 17, those who took metformin saw their body mass index measures fall—three by as much as eight to nine per cent—while those in the placebo group continued to put on pounds. The average weight difference after the study was six pounds: While the kids on metformin maintained their weight while growing taller, the children on placebo grew in both weight and height.

“For the kids who need these medications, we’re trying to prevent long-term health complications from obesity like diabetes and stroke,” says neurologist Evdokia Anagnostou, lead investigator in Holland Bloorview’s autism research centre. “Children on these meds put on more than a pound a week and we think the mechanism for that is insulin resistance. As a result, the kids eat more, the appetite goes up and they store more fat.”

Metformin decreases insulin resistance and has been associated with stopping or reversing weight gain in adults who take antipsychotics.

The children in the Holland Bloorview study were already overweight. Future research will look at whether adding metformin when a child first begins taking antipsychotics prevents weight gain altogether.