Electroconvulsive therapy (ECT) is one of the most robust antidepressant treatments available. However, there is the potential for significant acute and longer term adverse cognitive effects with ECT and the antidepressant response requires multiple treatment sessions, increasing risk of adverse effects. Further, antidepressant response to ECT is often less than maximal and relapse is common. Growing preclinical and clinical evidence of the rapid-acting antidepressant properties of the anesthetic agent ketamine suggests the use of ketamine anesthesia as a strategy to increase rate of response and shorten treatment course in the administration of ECT. In addition, preclinical and clinical evidence suggests the potential of ketamine to decrease the adverse cognitive effects associated with ECT.~The investigators propose a pilot study to measure both acute therapeutic efficacy and cognitive side effects of ECT using ketamine compared to methohexital in depressed patients. The investigators will also explore other parameters of ECT such as seizure duration and morphology, as well as hemodynamic and behavioral changes.
The primary objectives of this study are to investigate the potential for ketamine anesthesia to increase the antidepressant efficacy of Electroconvulsive therapy (ECT) and to decrease acute ECT-induced adverse cognitive effects.