Predictors of the longitudinal course of postpartum depression following interpersonal psychotherapy

Objective: We examined the course and predictors of postpartum depression in the 18 months following interpersonal psychotherapy (IPT). Method: We enrolled 120 community women with major depression in a 12-week randomized trial of individual IPT during the postpartum period (O’Hara, Stuart, Gorman, & Wenzel, 2000). At 6, 12, and 18 months posttreatment, women participated in clinical interviews to establish the course of depression over the previous 6 months. We used survival analyses to characterize recovery and recurrence in the follow-up and growth curve modeling techniques to identify predictors of change in depression during the follow-up period. Potential predictors included severity, chronicity, and personal history of depression. Results: Of 35 women who recovered with acute treatment, 20 (57%) achieved sustained recovery during follow-up; average time to recurrence was 33.40 weeks (SD 18.43 weeks). Over 80% of women who did not recover with acute treatment experienced recovery at some point during follow-up; average time to recovery was 28.60 weeks (SD 17.51 weeks). Time depressed each month decreased over the follow-up period. Posttreatment depressive severity and length of the index episode predicted changes in depression over time. Posttreatment depression severity, personal history of depression, and weeks of treatment in the follow-up were significant predictors of time depressed during follow-up. Conclusions: IPT resulted in long-term benefits past the termination of acute treatment, even for women who did not initially recover. Though the vast majority of women who did not recover with acute treatment did recover during the follow-up period, continuation of IPT may accelerate the process.