Subjective and objective memory effects after electroconvulsive therapy for depressive disorders - systematic review and meta-analysis.

INTRODUCTION

Both objective and subjective memory functioning may be affected by electroconvulsive therapy (ECT). However, the relationship between objectively measured memory performance and subjective memory complaints has not been systematically examined.

METHODS

PubMed, Embase, Web of Science, Scopus, CINAHL were searched for studies of patients with a major depressive episode treated with ECT, assessing both subjective and objective memory, before and after an ECT course. Four separate meta-analyses examined the change within subjects in immediate recall, delayed recall, and autobiographical memory and subjective memory functioning.

RESULTS

Twelve studies involving 837 participants were included. Within one month post-ECT, weighted effect sizes (ESs) indicated no significant change in immediate recall, a significant decline in delayed recall and autobiographical memory, and a significant improvement in subjective memory. Beyond one month post-ECT, immediate and delayed recall significantly improved, autobiographical memory significantly declined while subjective memory significantly improved. Substantial heterogeneity remained across all meta-analyses despite sensitivity and moderator analyses. Moderator analysis indicated that average mood improvement was not associated with ESs for subjective memory within one month post-ECT, but was associated with them thereafter. Studies with a larger decline in autobiographical memory showed a smaller improvement in subjective memory. Similar associations between subjective memory and verbal learning were not observed.

CONCLUSION

Studies with smaller average subjective memory improvement are charactered by larger average autobiographical memory decline immediately following ECT but not beyond one month post ECT. Note, however, that study level associations do not necessarily imply patient level associations. Future research in ECT should focus on the relation between autobiographical and subjective memory complaints and distinguish between acute and long-term cognitive effects.