A Post-Hoc Analysis of Depressive Disorders in Patients with Type 2 Diabetes

Background/Objectives: This study is an investigation of the occurrence, remission and recurrence of major depressive disorders (MDDs) in adults with type 2 diabetes (T2DM). Methods: Interviews were conducted with individuals (N = 176) who met the criteria for MDD using the Structured Clinical Interview for the DSM-IV-TR (SCID). Results: N = 176 T2DM adults, with a mean (SD) age of 55.5 (10.4) years, 74% of whom were female and 62% were white, completed the Structured Clinical Interview for the DSM-IV-TR (SCID). A mean (SD) number of 1.8 (0.9) episodes of major depression (MDD) were recorded from birth to the date of interview, with a mean (SD) onset age of the first episode of 40.4 (15.9) years. Median (IQR) MDD episode duration was 13.9 (5.6-31.9) months and the median (IQR) cumulative lifetime exposure duration to MDD was 33 (12.9-63.1) months. Kaplan-Meier survival analysis along with the frailty model, to account for the correlation among multiple recurrences or remissions within a subject, indicated that the median first episode duration was shorter than the median second episode duration (14 vs. 37.9 months, p < 0.0001). Of those who had at least three episodes, the median second episode duration was shorter than the median third-episode duration (13.0 vs. 28.0 months, p = 0.006). The median recurrence time following first remission was significantly longer than the median recurrence time following second remission (138.0 vs. 80.6 months, p = 0.02). Conclusions: These results document that clinical depression is recurrent in adults with T2DM. Moreover, depressive episodes in individuals with T2DM are persistent well beyond episode durations observed in the general population.