Does the Loss of Autobiographical Memories Contribute to the Therapeutic Effect of Electroconvulsive Therapy?

OBJECTIVE: For decades, a persistent claim has been that autobiographical memory loss after electroconvulsive therapy (ECT) for depression might actually contribute to ECT efficacy by reducing or even eliminating autobiographical memories. To test this claim, the primary aim of this study is to examine the association between autobiographical memory loss and remission of depression. The hypothesis is that remitted patients have more autobiographical memory loss after ECT compared to non-remitted patients. METHODS: In 71 patients with major depressive disorder undergoing ECT, autobiographical memory consistency (Kopelman Autobiographical Memory Interview) and depression severity (Montgomery-Åsberg Depression Rating Scale) were assessed before and within 1 week after treatment. Logistic regression analyses were conducted to examine the association between both autobiographical memory loss (i.e., memory consistency) and remission (MADRS < 10), including age, episode duration, baseline MADRS score, and treatment condition as covariates. RESULTS: All logistic regression models were significant. The overall autobiographical memory consistency-score (OR = 1.072, 95% CI [1.018-1.130], p = 0.009) and the consistency-score for recent memories (OR = 1.043, 95% CI [1.006-1.082], p = 0.021) were significantly associated with the odds of remission but in the opposite direction of the hypothesis. A higher age and shorter episode duration further increased the likelihood of remission. Additionally, post hoc analyses showed that the trajectories of autobiographical memory performance over time differed between remitters and non-remitters, indicating a slight decrease in autobiographical memories for more recent events in non-remitters and no change in remitters. CONCLUSIONS: This study shows that, contrary to the hypothesis, remitted patients have less autobiographical memory loss, particularly for recent memories than non-remitters. This refutes the premise that the loss of autobiographical memories contributes to the therapeutic effectiveness of ECT.