Seizure duration and related issues in ect for endogenous depression.

In a study comparing sinusoidal wave and brief-pulse ECT in endogenous depression, seizure duration was monitored by the cuff method in 29 patients over 180 treatment sessions. Mean seizure duration across all treatments was 26.5 secs, and the mean for individual patients across their ECT course ranged from a minimum of 15.7 secs to maximum of38.5 secs. Regression analysis found no variable which significantly predicted mean seizure duration. Of the 22 good responders in the study, response to ECT was associated with a mean seizure duration of secs in 1 patient, ando cs in 11 patients; as just 2 of 7poor responders to ECT had a mean seizure duration of <20 secs in 1 patients, <25 secs in 11 patients, of the 22 good responders in the study; as just 2 of 7 poor responders to ECT had a mean seizure duration of <25 secs, it appears that a cuff seizure duration of over 20 secs may suffice for the seizure to be therapeutic in depression. With (constant current) brief pulse ECT, seizure threshold significantly increased with successive ECTs; thresholds did not however differ between the good and poor responders. There was a trend for seizure duration to decrease over time; again, good and poor responders did not differ. These findings provide little support for the anticonvulsant hypothesis for the antidepressant effect of ECT, but support the literature that ECT exerts an anticonvulsant effect.