Predictors of Treatment Response in Patients with Treatment-Resistant Depression: Outcomes of a Randomized Trial

Objective: This report aims to compare the effectiveness between electroconvulsive therapy (ECT) and transcranial direct stimulation (tDCS) among patients with treatment-resistant depression (TRD) and the associated factors. Methods: This was a secondary data analysis of a randomized, controlled, open-label trial conducted from 1 July 2018, to 31 December 2018. The dataset of 90 patients included in the study was retrieved from Mendeley Data. Patients with TRD were randomized 1:1 into either receiving ECT or tDCS. A good treatment response was determined as an improvement from the Hamilton Depression (HAM-D) baseline score at a rate of more than or equal to 50% at the end of a 2-week intervention. A mixed-effect logistic regression was performed to explain the hierarchical data structure of predictors to successful treatment outcome. Results: The largest magnitude of change was consistently observed in the ECT treatment arm across both HAM-D score and the clinical global impression severity scale (CGI-S) scale (p < 0.001). Lower baseline HAM-D scores (OR: 0.72, 95% CI: 0.58, 0.92), lower baseline CGI-S scale (OR: 0.30, 95% CI: 0.17, 0.55), and ECT as the choice of treatment modality (OR: 14.0, 95% CI: 5.08, 38.58) independently predicted successful therapy among TRD patients, while modelling with multiple logistic regression determined that low socio-economic status (aOR: 20.01, 95% CI: 1.89, 211.47), ECT (aOR: 31.7, 95% CI: 6.32, 159.0) and a lower baseline CGI-S scale (aOR: 0.18, 95% CI: 0.06, 0.57) were significantly predictive of a positive treatment outcome among patients with TRD. Conclusions: ECT was more effective in alleviating depressive symptoms in TRD as compared to tDCS.