Anterograde and retrograde amnesia following electroconvulsive therapy: A controlled longitudinal study accounting for time and depression.

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.