Anterograde Amnesia during Electroconvulsive Therapy: A Prospective Pilot-Study in Patients with Major Depressive Disorder.

Electroconvulsive therapy (ECT) is considered an effective treatment for major depression with melancholic features. However, neurocognitive side-effects such as anterograde amnesia still regularly occur. The present study aims to evaluate the severity and course of anterograde amnesia in severely depressed patients undergoing ECT. In a prospective naturalistic study, anterograde memory function was assessed among inpatients who underwent ECT (n = 11). Subjects met DSM-IV criteria for major depressive disorder. Recruitment took place between March 2010-March 2011 and March 2012-March 2013. Controls treated with antidepressants (n = 9) were matched for age, gender and depression severity. Primary outcome measure was immediate recall; secondary outcome measures were delayed recall, recognition, and visual association. Differences were tested using repeated measures ANOVA and paired t-tests. Correlations with hypothesized covariates were calculated. In patients with major depressive disorder, ECT had a significant effect on delayed memory function (p<0.01 with large effect sizes). Findings on immediate recall were less consistent. Four weeks after treatment discontinuation, these memory functions had recovered. Age was identified as a very important covariate. The main limitations of our study are its naturalistic design, possibly compromising internal validity, and its small sample size. However, if these findings can be reproduced in a more comprehensive study group, then the possible induction of anterograde amnesia is not a justifiable reason for clinicians to disregard ECT as a treatment option

Mean values (SD) of all outcome measures, between-group comparisons, and effect sizes at each time of assessment.

<p>Mean values (SD) of all outcome measures, between-group comparisons, and effect sizes at each time of assessment.</p

Results for repeated measures ANOVA on immediate recall (with +/- 1 SE).

<p>Repeated measures ANOVA showed no significant differences. However, the within-group effect (using paired t-tests) was significant between T2 and T3 in the ECT group (1; p = 0.03) and between T0 and T3 in the control group (2; p = 0.02). T0 = baseline. In the ECT group, T1 = 2 weeks after start of ECT; T2 = 4 weeks after start of ECT; T3 = 4 weeks after discontinuation of ECT. In the control group, assessments are defined as follows: T1 = 2 weeks after reaching adequate blood level of antidepressants; T2 = 4 weeks thereafter; T3 = 8 weeks thereafter.</p

Characteristics of the two study groups.

<p>Characteristics of the two study groups.</p

Flowchart of patient selection in the electroconvulsive therapy (ECT) group.

<p>%M = proportion of missing values over T0-T3; ^#incomplete data were replaced by mean values; *assessments are defined as follows: T0 = baseline. In the ECT group, T1 = 2 weeks after start of ECT; T2 = 4 weeks after start of ECT; T3 = 4 weeks after discontinuation of ECT. In the control group, assessments are defined as follows: T1 = 2 weeks after reaching adequate blood level of antidepressants; T2 = 4 weeks thereafter; T3 = 8 weeks thereafter. RAVLT = Rey Auditory Verbal Learning Test; VAT = Visual Association Test; HRSD = Hamilton Rating Scale for Depression; MMSE = Mini Mental State Examination.</p