FRIDAY, Dec. 1, 2006 (HealthDay News) -- While increasing numbers of children and teens are being treated for psychiatric illness with medications called atypical antipsychotics, many experience significant weight gain while on these drugs -- as much as a pound or more a week.
However, a new study suggests that the diabetes drug metformin may be able to put the brakes on that weight gain.
During the 16-week study period, children taking metformin along with atypical antipsychotics lost a slight amount of weight, while those given a placebo along with their psychiatric medications gained nearly 9 pounds.
"For someone with a major psychiatric diagnosis, there's a stigma attached to that to begin with, then if you add obesity on top of that, there's an additional stigma," noted the study's lead author, Dr. David Klein, an endocrinologist at Cincinnati Children's Hospital Medical Center. "Now, if people do gain weight, there's an effective treatment to control weight gain."
Results of the study are in the December 2006 issue of the American Journal of Psychiatry.
Atypical antipsychotic medications include risperidone (brand name Risperidal), olanzapine (brand name Zyprexa) and quetiapine (brand name Seroquel). These medications are used to treat a variety of psychiatric illnesses, such as bipolar disorder and schizophrenia.
Increased appetite and accompanying weight gain are common side effects attributed to the drugs.
"We know that appetite increases, but the mechanism behind that isn't fully clear," said Dr. Glenn Hirsch, medical director of the New York University Child Study Center.
Klein said his interest was piqued when he saw a patient with type 2 diabetes who was "eating voraciously." Once he took her off the antipsychotic medications, her diabetes went away. Unfortunately, her psychiatric symptoms quickly returned. Once back on the atypical antipsychotics, her diabetes came back.
That suggested, said Klein, "that there was some 'diabeticogenic' effect of these agents," and that insulin resistance might play some role in the excess weight gain.
So, for the current study, the researchers wanted to learn if medication that can improve the body's use of insulin might also halt the weight gain these children experienced.
For the study, the researchers randomly assigned a group 39 children between the ages of 10 and 17 to receive either 850 milligrams of metformin daily or a placebo. All of the children were taking atypical antipsychotic medications, and all had experienced at least a 10 percent gain in body weight in less than a year.
The study lasted four months. During that time, those taking the placebo gained an average of 8.8 pounds while those on metformin lost 0.2 pounds.
Additionally, there was a significant reduction in insulin resistance in the group taking metformin.
Klein said there were no serious side effects in the treatment group, and the drug was generally well-tolerated.
"For people who need these medicines and start to gain weight, this study suggests we can stop the weight gain," said Hirsch.
However, both Klein and Hirsch said that larger studies of longer duration should be conducted to confirm these findings.
In the meantime, Klein said he expects that physicians will try using metformin if they have patients who are gaining weight while taking atypical antipsychotics.
Hirsch said that if you or your child is taking these drugs, and you've done everything you can to prevent weight gain, including consulting a nutritionist and exercising, but weight gain continues, you should talk to your doctor about possibly trying metformin.
"We have a critical issue here. Certain kids need this type of medication and are helped by it, but we don't want to cause any additional problems. If you have a child who's gaining weight on this medicine, there may be a treatment that can stop the weight gain. It's certainly worth talking with your physician about it," said Hirsch.
To learn more about antipsychotic medications, visit the National Institute of Mental Health.