Characteristics of responders and nonresponders to brief-pulse right unilateral ECT in a controlled clinical trial

In a double-blind, randomized controlled study of electroconvulsive therapy (ECT) in patients with major depression, 7 of the 17 patients allocated to the right unilateral group failed to respond to treatment. The nonresponde rs were subsequently openly treated with bitemporal treatment, which produc ed an acceptable outcome in these cases of right unilateral treatment failu re. This paper describes the clinical outcome. electrophysiological charact eristics (impedence, estimated seizure threshold, and change in threshold), and the degree to which stimuli exceeded threshold in the responder and no nresponder groups. Responders had lower seizure thresholds and longer seizu res than nonresponders. In comparison with nonresponders, responders showed trends toward greater impedance and treatment at a somewhat greater degree above threshold during the first few treatments. Threshold change with tre atment was found not to be related to clinical outcome. Early identificatio n of patients likely to respond to low-dose right unilateral ECT, together with the avoidance of benzodiazepine prescription during ECT, may permit ma ny patients to receive low-dose right unilateral ECT successfully and with a minimum of cognitive impairment.