ECT: Clinical variables, seizure duration, and outcome

The ability to predict treatment response in patients administered electroconvulsive therapy remains limited. Variables such as the duration of the individual seizure or the cumulative seizure duration have been reported to relate to outcome in a 'threshold' or 'therapeutic window' model. In this study, total seizure time, as measured by bifrontal electroencephalogram (EEG) electrodes, did correlate with outcome (r(s) = 0.43, p < 0.01). In addition, 88% of patients with a cumulative seizure time exceeding 300 s responded favorably (χ² = 6.80, p < 0.01). This provides support for the concept of the minimum threshold of accumulated seizure time necessary for clinical response. However, no evidence of an upper limit of benefit suggesting a 'therapeutic window' was found.