ECT vs. Esketamine

Treatment-resistant depression (TRD) is a common cause of disability and one of the most common psychiatric disorders worldwide. Electroconvulsive therapy (ECT) is currently the most effective treatment for TRD. Recent developments showed esketamine to be a rapid-acting and effective antidepressant drug and it has been hailed as a breakthrough in treating TRD. Common treatment algorithms for TRD list ECT as a treatment option, but esketamine has not yet found its exact position in those algorithms. To the investigators' knowledge, a longitudinal, randomized controlled trial comparing the efficacy of ECT and intranasal esketamine in TRD patients has not been conducted. Furthermore, the investigators intend to measure effects of ECT and intranasal esketamine on brain connectivity and structure, using functional magnetic resonance imaging (fMRI). In this study, inpatients with TRD at the University Hospital for Psychiatry I, Medical University Innsbruck, will be randomized to ECT or intranasal esketamine. Short- and medium-term treatment effects on functional and structural connectivity in the brain will be determined using fMRI.