Patients meeting the criteria for major depressive disorder are the most obvious candidates for treatment. A therapeutic trial may also benefit those patients with persistent depression symptoms that fall short of these criteria but, nevertheless, are associated with sustained impairments in function. Some patients or professionals have a preference for either psychotherapy or antidepressant medication; others may desire a combined approach. Consideration of the individual's symptom picture may provide a basis for treatment selection; the treatment of choice for depression dominated by somatic symptoms might be medication, whereas psychotherapy would be more effective for depression characterized by existential difficulties.
The presence of diabetes and its myriad physical complications can make the selection of depression treatment even more difficult. Conventional tricyclic antidepressants have long been used in primary care and have proved beneficial in regulating sleep. However, the potential for weight gain, anticholinergic side effects, orthostatic hypotension and other adverse cardiovascular side effects can be harmful for patients with diabetes. Furthermore, one study showed that TCAs may worsen glycemic control in patients with diabetes (Lustman et al., 1997b). These researchers found that although nortriptyline (Aventyl, Pamelor) was effective in treating depression, it had an adverse hyperglycemic effect that was unrelated to the medication's effect on weight.
Selective serotonin reuptake inhibitors and other newer antidepressants do not seem to cause hyperglycemia in patients with diabetes. These agents may in fact improve glycemic control, as was demonstrated in a recent trial using fluoxetine (Prozac) (Lustman et al., 2000b). The SSRIs are as effective as TCAs in treating depression but have less problems with weight gain and sedation as side effects. Side effects like sexual dysfunction, gastrointestinal distress and agitation are common and must also be considered, however.
Psychotherapy offers a unique alternative to medication; it has shown to be effective in treating depression, in addition to improving glycemic control, in patients with diabetes (Lustman et al., 1998).
Conclusion
Depression is a prevalent and recurrent condition among patients with either type 1 or type 2 diabetes. This psychiatric disorder complicates the medical disease by promoting poor glycemic control and increasing the risk of diabetes complications. Treatment of depression has significant favorable effects on mood and quality of life, as well as beneficial effects on glycemic control. The presence of diabetes complications or hyperglycemia decreases the likelihood of recovery during depression treatment and increases the probability of recurrence following treatment. Optimal treatment of depression in patients with diabetes may require a comprehensive approach that couples specific depression treatment with focused efforts to improve glycemic control.
Acknowledgement
Dr. Lustman's research on diabetes and depression was supported in part by grants DK36452 and DK53060 from the National Institutes of Health.
Dr. Lustman is professor of medical psychology in the department of psychiatry at Washington University in St. Louis School of Medicine and is recognized for his research on the interaction of psychiatric illness and diabetes. He serves on the editorial board of Clinical Diabetes and the grant review panel of the American Diabetes Association.
Mr. Anderson is clinical research associate in the department of psychiatry at Washington University in St. Louis School of Medicine.
