Subjective memory complaints after electroconvulsive therapy: systematic review

Abstract

Attribution-NonCommercial-NoDerivatives licence (http:// creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is unaltered and is properly cited. The written permission of Cambridge University Press must be obtained for commercial re-use or in order to create a derivative work. Aims and method Few studies have looked at subjective memory impairment from electroconvulsive therapy (ECT) after treatment completion. We aimed to systematically review all available evidence for subjective post-treatment effects. Results We included 16 studies in this review. There was considerable between-study heterogeneity in clinical population, ECT modality and assessment scales used. The most common assessment scale (eight studies) was the Squire Subjective Memory Questionnaire. The majority of studies reported an improvement in subjective memory after ECT, which correlated with improved depression scores. Subjective complaints were fewer in studies that used ultra-brief pulse ECT. Longer pulse widths were associated with more subjective complaints, as was female gender and younger age of treatment in the largest study. Clinical implications There is considerable heterogeneity between studies, limiting meaningful conclusions. Ultra-brief pulse ECT appears to result in fewer subjective complaints. Declaration of interest None. Electroconvulsive therapy (ECT) is an effective treatment for major depression; however, there is debate around the specific long-term effects of the treatment on memory and the acceptability of this to patients. 1 There is wide variation in the post-treatment satisfaction rates after ECT, with previous studies showing that the percentage of patients who would consider having a second course of ECT varies between 36% and 98%. 2 Multiple studies have shown that dissatisfaction with ECT is related to feeling under-informed of potential side-effects. 3-7 Pre-procedural fear and post-procedural assumptions that deleterious cognitive changes were a direct result of the treatment have been identified as the two areas most likely to lead to a negative view of ECT. 8 Evidence suggests that clin-icians tend to overestimate the effects of medical treatments and underestimate harm, so being able to accurately quantify the additional risk that ECT poses to subjective memory independent of the effects of depression would help both clin-icians and patients alike and may improve outcomes. 9,10 This review aims to summarise all studies that have assessed the post-treatment effects of ECT on meaningful memory loss. Methods This systematic review was completed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines (Fig. 1). Inclusion criteria Studies measuring subjective memory at baseline followed by at least one measurement after the completion of treatment, using a clearly described scale (such as the Squire Subjective Memory Questionnaire, SSMQ 11), or questions that specifically assessed subjective memory were included. A follow-up period of at least 24 h after the completion of therapy was considered sufficient to allow enough time for the acute effects of the final seizure to have passed and no limit was placed on the maximum length of follow-up. Both prospective and retrospective studies were included. Only published studies were included and studies in all languages were considered. Studies measuring memory only during treatment were excluded. Squire's original studies from 1979 were excluded. Information sources The online databases PubMed, Google Scholar, Embase, PsychINFO and Cumulative Index of Nursing and Allied Health Literature (CINAHL) were searched for eligible studies. The following search terms and Boolean operators were used in PubMed as examples: 'subjective AND (ECT OR electroconvulsive)', 'memory AND (ECT OR electroconvulsive').