Effect of Previous Electroconvulsive Therapy on Subsequent Response to Transcranial Magnetic Stimulation for Major Depressive Disorder

Objectives Patients with major depressive disorder (MDD) who received electroconvulsive therapy (ECT) often seek transcranial magnetic stimulation (TMS) therapy as a less invasive treatment option. How prior history of ECT and its responsiveness may affect TMS treatment outcomes for MDD is unclear. We aim to contribute evidence to this important clinical question. Materials and Methods Retrospective naturalistic TMS treatment data from n = 257 MDD patients. Three sets of analyses were conducted: History of past exposure to ECT (n = 71, "+ECT" vs. n = 186 ECT-naive, "-ECT") was examined as a potential predictor of TMS outcomes (measured by two self-report scales); A subset of n = 38 +ECT patients with adequate ECT trials in current depression episode were compared with -ECT patients blindly matched on clinical variables associated with TMS outcomes; for a subset with available data, TMS outcomes were explored in relation to positive/negative response to prior ECT. Results Compared to -ECT, +ECT patients more likely had past psychiatric hospitalizations (p < 0.01) and were more severely depressed at baseline (p = 0.07). Response (p = 0.07) and remission (p = 0.02) rates were higher in -ECT than +ECT groups on one scale. However, comparison between the subsets (n = 38 each) matched on confounding factors did not find history of ECT to be a significant independent predictor of TMS outcomes. Differential responsiveness to ECT and ECT treatment characteristics did not significantly impact TMS outcomes. Conclusions Although limited by the retrospective nature of this analysis, the results suggest that history of the past ECT, regardless of responsiveness to ECT, may not independently portend differential TMS treatment outcomes.