OBJECTIVE: Several clinical variables assumed to be predictive of electroconvulsive therapy (ECT) outcome in major depressive disorder show substantial interrelations. The current study tries to disentangle this interdependence to distill the most important predictors of treatment success to help improve patient-treatment matching.
METHODS: We constructed a conceptual framework of interdependence capturing age, episode duration, and treatment resistance, all variables associated with ECT outcome, and the clinical symptoms of what we coin core depression, ie, depression with psychomotor agitation, retardation, psychotic features, or a combination of the three. The model was validated in a sample of 73 patients with a major depressive episode according to DSM-5 treated twice weekly with ECT (August 2015-January 2018) using path analyses, with the size and direction of all direct and indirect paths being estimated using structural equation modeling. Reduction in Montgomery-Asberg Depression Rating Scale (MADRS) scores during treatment was the ECT outcome measure.
RESULTS: The baseline presence of psychomotor agitation, retardation, and/or psychotic symptoms strongly correlated with beneficial ECT outcome (z = 0.84 [SE = 0.17]; P < .001), and the association between age and the effect of ECT appears to be mediated by their presence (z = 0.53 [SE = 0.18]; P = .004). There was no direct correlation between age and ECT response (P = .479), but there was for episode duration and ECT outcome (z = -0.38 [SE = 0.08]; P < .001).
CONCLUSIONS: ECT is a very effective treatment option for severe depressive disorder, especially for patients suffering from severe depression characterized by the presence of psychomotor agitation, psychomotor retardation, psychotic symptoms, or a combination of these 3 features, with the chance of a beneficial outcome being reduced in patients with a longer episode duration. Age may heretofore have been given too much weight in ECT decision making.
TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02562846.