Cognitive behavior therapy for depression in type 2 diabetes mellitus. A randomized, controlled trial.

BACKGROUND Psychotherapy is the principal nonpharmacologic method for the management of depression, but its usefulness for depressed patients with diabetes remains unknown. OBJECTIVE To assess the efficacy of cognitive behavior therapy (CBT) for depression in patients with diabetes. DESIGN Randomized, controlled trial. SETTING Referral-based academic medical center. PATIENTS 51 patients with type 2 diabetes and major depression. INTERVENTION Patients were assigned either to a group that received 10 weeks of individual CBT or to a control group that received no specific antidepressant treatment. All patients participated in a diabetes education program to control for the effects of supportive attention and the possible influence of enhanced diabetes control on mood. MEASUREMENTS Degree of depression was measured by using the Beck Depression Inventory; glycemic control was measured by using glycosylated hemoglobin levels. Outcomes were assessed immediately after treatment and 6 months after treatment. RESULTS The percentage of patients achieving remission of depression (Beck Depression Inventory score < or = 9) was greater in the CBT group than in the control group: posttreatment, 85.0% of patients in the CBT group (17 of 20) compared with 27.3% of controls (6 of 22) achieved remission (difference, 57.7 percentage points [95% CI, 33 to 82 percentage points]) (P < 0.001); at follow-up, 70.0% of patients in the CBT group (14 of 20) compared with 33.3% of controls (7 of 21) achieved remission (difference, 36.7 percentage points [CI, 9 to 65 percentage points]) (P = 0.03). Post-treatment glycosylated hemoglobin levels were not different in the two groups, but follow-up mean glycosylated hemoglobin levels were significantly better in the CBT group than in the control group (9.5% compared with 10.9%; P = 0.03). CONCLUSIONS The combination of CBT and supportive diabetes education is an effective nonpharmacologic treatment for major depression in patients with type 2 diabetes. It may also be associated with improved glycemic control.