Effects of stimulus intensity on the efficacy of bilateral ECT in schizophrenia: a preliminary study

Abstract Background: This preliminary study examined the effects of electrical stimulus intensity on the speed of response and efficacy of bilateral electroconvulsive therapy (ECT) in the treatment of schizophrenia. Methods: Sixty-two patients with schizophrenia received combination treatment with bilateral ECT and flupenthixol. Using a randomized, double-blind design, the effects of three dosages of the ECT electrical stimulus were examined. Patients were treated with a stimulus intensity that was just above seizure threshold, two-times threshold, or four-times threshold. Assessments of outcome used the Brief Psychiatric Rating Scale, Global Assessment of Functioning, and the Mini-Mental State Exam. Results: Thirty-three of sixty-two patients met remitter criteria, including maintaining improvement over a 3-week stabilization period. The dosage groups were equivalent in the number of patients who met remitter criteria. The low-dose remitter group ( n = 11) received more ECT treatments and required more days to meet remitter status than both the twofold ( n = 11) and fourfold remitter groups ( n = 11). There was no difference among the groups in change in global cognitive status as assessed by the Mini-Mental State Exam. Conclusions: This preliminary study indicates that treatment with high-dosage bilateral ECT speeds clinical response in patients with schizophrenia. There may be a therapeutic window of stimulus intensity in impacting on the efficacy of bilateral ECT, which needs further study. A more sensitive battery of cognitive tests should be used in future research.