BACKGROUND ECT is a well-established treatment for severe depression. The available data on psychosis are limited, but reliable. Its therapeutic potential relies on the induction of a generalized seizure. Besides other narcotics, methohexital and etomidate are used for general anesthesia in ECT. Since prolonged seizures have been reported following the use of etomidate, it can be deduced that the substances might differ in their anticonvulsant properties, resulting in a lower increase in stimulus intensity during the course of treatment under etomidate. Besides this hypothesis, we aimed to investigate the differential effects of etomidate and methohexital on clinical features, ECT parameters and side effects of the treatment. METHODS We performed a retrospective analysis of treatment data of patients with affective and psychotic diagnosis who received general anesthesia for ECT either with etomidate or with methohexital. RESULTS ECT with etomidate and methohexital was equally effective. During the course of therapies the administered electric charge increased significantly and equally in both treatment groups. In the methohexital group, but not in the etomidate group, electroencephalographic seizure duration had a declining trend during the course of therapies. We observed more side effects during and immediately after ECT in the methohexital group than in the etomidate group. CONCLUSIONS The limitations of this study are that the patients received various psychotropic co-medications, which influence ictal parameters differently, and, secondly, the study is based on a retrospective analysis. CONCLUSIONS The results of our analysis suggest that etomidate and methohexital affect ictal parameters to different extents. Longer seizure duration and fewer side effects are in favor of etomidate.