Enduring effects of Preventive Cognitive Therapy in adults remitted from recurrent depression: A 10 year follow-up of a randomized controlled trial

Background: Prevention of recurrence is a challenge in the management of major depressive disorder (MDD). The long-term effects of Preventive Cognitive Therapy (PCT) in preventing recurrence in MDD are not known.

Methods: A RCT comparing the addition of PCT to Treatment As Usual (TAU), versus TAU including patients with recurrent depression who were in remission at entry (N=172). PCT consisted of eight weekly group sessions. TAU involved standard treatment. Primary outcome is time to first recurrence of a depressive episode as assessed by blinded interviewers over 10 years based on DSM-IV-TR criteria.

Results: Also over 10 years, the protective effect of PCT was dependent on the number of previous episodes a patient experienced. The protective effect intensified with the number of previous depressive episodes (Cox regression; p=.004, Hazard ratio=.576, 95% CI=.396-.837) and is mainly established within the first half of the 10 year follow-up period. For patients with more than three previous episodes (52% of the sample), PCT significantly increased the median survival time (713.0 days) versus patients that received TAU (205.0 days). No enduring effects were found on secondary outcomes.

Limitations: Dropout rates were relatively high for secondary outcomes, but relatively low for the primary outcome. Results were comparable after multiple imputation.

Conclusions: PCT in remitted patients with multiple prior episodes has long-term preventive effects on time to recurrence. To reduce recurrence rates, booster sessions might be necessary. A personalized medicine approach might be necessary to reduce recurrence rates even further.