RESUMO
BACKGROUND: Electroconvulsive therapy (ECT) is an effective treatment for depression, mania, and refractory schizophrenia. Its tolerability profile is established for acute treatment, but less is known regarding the effects of longer treatment courses, particularly on cognitive performance. OBJECTIVES: To assess the effect of the long-term ECT on cognition. METHODS: We searched CINAHL, EMBASE, PsychInfo and Pubmed, for the period between January 1, 2010, and June 30, 2022, in English or French, for randomized controlled trials, prospective or retrospective studies of ECT continued for at least 2 months for the treatment of mood or schizophrenic disorders and which measured cognition before and at the end of treatment. Non-peer reviewed records were excluded. The Cochrane Risk of Bias tool was used to assess study quality. Classical meta-analyses, with heterogeneity statistics (tau2, I2) were complemented with three level-meta-analysis and Bayesian Meta-analyses. RESULTS: Nine studies were included in the narrative and quantitative review. Controlled comparison at 6 months (k = 6, n = 334) and at 12 months (k = 3, n = 56), within-subject comparisons at 6 (k = 6, n = 218) and 12 months (k = 4, n = 147) showed no detrimental effect of maintenance or continuation ECT on cognition, with little to no heterogeneity. Bayesian analysis further confirmed that data better supported the no effects hypothesis. LIMITATIONS: Insufficient data resulted in imprecision in estimates. CONCLUSIONS: Continuation and maintenance ECT do not appear detrimental for cognitive performance. However, the low number of studies limit the interpretation of the results.