Antidepressant drugs show link to diabetes.

People taking antidepressant medication might be at increased risk of developing diabetes.

The unexpected association comes from a study of 3,187 people that was designed to find out whether type 2 diabetes could be prevented. All participants were at high risk of developing diabetes because they were overweight, sedentary, or had other risk factors. Some participants were directed to change their lifestyle, and some received diabetes medication or a placebo.

Roughly 6 percent of participants were taking antidepressants at the start of the study. Over the course of the trial, these people were nearly three times as likely to develop diabetes as were people not taking antidepressants, reports Richard R. Rubin of Johns Hopkins Medical Institutions in Baltimore.

However, people taking antidepressants who were also assigned to receive the diabetes medication metformin (brand name Glucophage) weren't any more likely to develop diabetes during the 3-year study than were people not on antidepressants, the researchers found.

It's unclear how antidepressants might contribute to type 2 diabetes or how metformin might offset such risk. "We don't have a clue as to what's going on, [but] the potential public health implications are substantial," Rubin says.

He counsels people not to change their medication based on the new study. "These are dramatic and striking findings that deserve further investigation," he concludes.--N.S.