Memory reactivation before electroconvulsive therapy does not offer significant benefits

Emotional memory reactivation before electroconvulsive therapy for depression did not offer significant benefits vs. control memory reactivation, according to results of a randomized clinical trial published in JAMA Network Open.

“Research indicates that when memories are reactivated they may become temporarily labile and require re-stabilization processes to be maintained, a process known as reconsolidation,” Dominique S. Scheepens, MD, of the department of psychiatry at University of Amsterdam in the Netherlands, and colleagues wrote. “Pharmacologic interventions that disrupt the re-stabilization processes may selectively weaken the reactivated memory. Studies in the 1960s and 1970s reported that electroconvulsive treatment disrupted reactivated memories in rats and that reactivation of obsessive-compulsive symptoms in patients before applying [electroconvulsive therapy] (ECT) increased effectiveness.”

Results of a 2014 study suggested that one ECT session could selectively impair memory for a learned emotional story if reactivated right before an ECT session. Thus, if one ECT session could weaken memory, several emotional memory reactivations (EMRs) among consecutive sessions might boost effectiveness of ECT, increase its rapid response times and reduce relapse rates following successful ECT, according to the researchers.

Scheepens and colleagues aimed to test this hypothesis in the current study, which they conducted in departments of psychiatry among three Netherlands hospitals. They randomly assigned 66 participants 1:1 to two parallel groups to received either EMR-ECT of control memory reactivation ECT (CMR-ECT) intervention prior to ECT sessions and used the Hamilton Depression Rating Scale (HDRS) to assess depression symptoms during and after ECT, with a follow-up period of 6 months. Participants had a primary diagnosis of unipolar major depressive disorder according to DSM-4 criteria, an ECT indication and were between ages 18 and 70. The investigators used the HDRS to evaluate depression scores and relapse rates within 6 months, and they analyzed them using logistic and linear multiple regression analyses.

Results showed response among 42.4% of patients, with a 50% decrease of symptom severity on the HDRS, regardless of the memory intervention. Among responders, 39.3% relapsed within 6 months. The intervention did not appear to significantly alter remission rates, mean HDRS scores after the ECT course, total mean number of required ECT sessions for response and relapse rates.

“Personalized reactivation of emotional memories just before ECT sessions for MDD was well tolerated but did not improve ECT efficacy, decrease the time to response, or reduce the relapse rate,” Scheepens and colleagues wrote. “This RCT highlights the difficulties of translating insights from laboratory research into clinical practice and may provide direction for future studies to further improve ECT for patients with severe MDD.”