A team of School of Medicine researchers found that an antidepressant medication may reduce the risk of recurrent depression and increase the length of time between depressive episodes in patients with diabetes.
“That’s important not only because people with diabetes will feel better if we can control their depression, but it’s also key to helping manage blood sugar,” said Patrick J. Lustman, Ph.D., principal investigator and professor of psychiatry. “As depression improves, glucose levels also tend to improve.”
Although depression affects about 5 percent of the general population, the rate is about 25 percent for patients with diabetes.
Lustman’s team previously demonstrated that treatment with antidepressants and psychotherapy is an effective way to treat depression in patients with diabetes, but often depression would quickly redevelop.
“As we better understand depression, it’s clear that for many patients, it is a chronic and recurring disease,” Lustman said. “That appears to be especially true for patients with diabetes compared with those otherwise free of medical illness.”
Although they knew that short-term treatment with antidepressants was helpful with mood and with control of blood glucose, team members didn’t know whether the drug could prevent the recurrence of depression in patients with diabetes. They also didn’t know what would happen to glucose levels in the months following successful depression therapy.
So Lustman teamed up with investigators at the University of Arizona and the University of Washington. They studied 152 patients with diabetes at the three sites.
The sample included patients with type 2 diabetes and patients with juvenile, or type 1, diabetes. Study participants averaged just over 50 years old, and they all had recovered from an episode of depression following treatment with sertraline (Zoloft).
After their depression was under control, half the patients continued to take sertraline while the other half took a placebo. Patients were followed for up to a year or until their depression recurred. During that time, investigators regularly measured blood-glucose levels by keeping track of hemoglobin A1C, which reflects an individual’s control of blood glucose over 2-3 months.
After a year, more than 65 percent of those still taking sertraline remained in remission from their depression. Only about 48 percent of those taking placebo were still in remission.
On average, those who continued to take sertraline stayed free of depression four times longer than those who did not. Blood-glucose levels remained lower in both groups of patients, as long as depression remained under control.
“That’s very important,” Lustman said. “We now know that controlling depression, by whatever method — exercise, activity, cognitive therapy or medication — improves the likelihood that blood glucose will be better controlled. That’s the key to preventing the complications of diabetes, such as eye disease, neuropathy and kidney disease.”