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

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.