Use of Zyprexa and other antipsychotics often cause weight gain, and can even lead to diabetes. Now, a diabetes drug seems to help prevent these side effects.

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."