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.