Lifetime Duration of Depressive Disorders in Patients With Type 2 Diabetes

Depression in patients with type 2 diabetes (T2D) is associated with long-term complications, disability, and early mortality. No studies have systematically examined the length of episodes and remission in adults with major depressive disorder (MDD) and T2D. This study examined the course of depressive disorders in patients with T2D and MDD.

Participants (N = 50) enrolled in a behavioral intervention for adults with T2D and MDD were interviewed using the Structured Clinical Interview for DSM-IV-TR to assess history of depressive disorders at baseline (lifetime history), postintervention, and 3-month follow-up. Onset and remission dates were recorded for all Axis I depressive disorders from birth to final interview.

Average number of MDD episodes was 1.8 with a mean duration of 23.4 months (SD 31.9; range 0.5-231.3). Over the life course, mean exposure to MDD was 43.1 months (SD 46.5; range 0.5-231.3). Kaplan-Meier survival curve analysis indicated median episode duration decreased with subsequent episodes (14 months, first episode; 9 months, second episode; P < 0.002). In patients with multiple depressive episodes, recovery time was shorter with each subsequent episode (P = 0.002). No differences in length of episode or remission were observed based on chronology of T2D diagnosis.

The overall exposure to depression in this sample of adults with T2D represents a substantial period of time that can contribute to negative medical and psychiatric outcomes. Recurrent episodes decrease in duration as do recovery periods, resulting in a waxing and waning pattern. Findings from this study underscore the need to effectively diagnose and treat depression in patients with T2D to minimize risk of future depressive episodes.