"That's important not only because people with diabetes will feel better if we can control their depression. It's also key to helping manage blood sugar," says 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 antidepressant drugs 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 says. "That appears to be especially true for patients with diabetes compared to 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, Lustman's team didn't know whether the drug could prevent the recurrence of depression in patients with diabetes. He 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, Tucson, and at the University of Washington, Seattle. They studied a total of 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 of age, and all had recovered from an episode of depression following treatment with sertraline (Zoloft®).
After their depression was under control, half of the study patients continued to take sertraline while the other half took an inactive 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 two to three months.
At one 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 continue to take medication. Blood glucose levels remained lower in both groups of patients, as long as depression remained under control.
"That's very important," Lustman says. "We now know that controlling depression, by whatever method -- whether with 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."
Lustman PJ, Clouse RE, Nix BD, Freedland KE, Rubin EH, McGill JB, Williams MM, Gelenberg AJ, Ciechanowski PS, Hirsch IB. Sertraline for prevention of depression recurrence in diabetes mellitus. Archives of General Psychiatry, vol. 63; pp. 521-529, May 2006.
Funding from the National Institutes of Health and an unrestricted educational grant from Pfizer Inc. supported this research.
Washington University School of Medicine's full-time and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine is one of the leading medical research, teaching and patient care institutions in the nation, currently ranked fourth in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children's hospitals, the School of Medicine is linked to BJC HealthCare.
Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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