Electroconvulsive therapy (ECT) may be accompanied by amnesia. However, the extent to which different memory subtypes are affected is unclear, as well-controlled longitudinal studies are sparse. We aimed to investigate short- and long-term effects of ECT on different aspects of memory.

We recruited patients with depression referred to ECT (n = 31) or other treatment (n = 21) and healthy participants (n = 29). We measured autobiographical (Columbia Autobiographical Memory Interview – Short Form), verbal (Verbal Learning Test – Delayed), and visual (Rey Complex Figure Test) anterograde memory at baseline (T1), post-ECT (T2), and 6-month follow-up (T3). We performed a repeated measures mixed ANOVA for each outcome. An ANCOVA explored whether age and cognitive reserve were associated with severity of amnesia. ClinicalTrials.gov: NCT04160286.

A substantial effect of ECT on autobiographical memory was indicated by a group-by-time interaction, F (3.45, 103.51) = 22.261, p < 0.001, partial η2 = 0.426. The effect remained stable, and inferior to control groups, at T3 (p < 0.001). A large effect of ECT on verbal anterograde memory was suggested by a group-by-time interaction, F (2, 68) = 6.138, p = 0.004, partial η2 = 0.153, reflecting transient impairment after ECT (p = 0.009). No ECT-related decline in visual anterograde memory was observed (p = 1.0). Neither age nor cognitive reserve was associated with degree of amnesia.

Our findings suggest that ECT may be associated with autobiographical amnesia, potentially lasting at least 6 months, and transient verbal, but not visual, anterograde amnesia.