Factors influencing treatment frequency of continuation ECT in schizophrenia.

Although continuation and maintenance electroconvulsive therapy (C-ECT and M-ECT) have been used since 1943, no studies reported data that might help guide the selection of C-ECT frequency. This two-phase study was conducted in 32 chronic schizophrenic patients, with history of prior responsiveness to ECT to determine clinical variables associated with treatment frequency of C-ECT. After acute combination treatment with ECT and neuroleptics (Phase I), all patients received weekly ECT during the first 4 weeks of C-ECT (Phase II). They were then assigned to receive either weekly (n = 8) or biweekly (n = 24) ECT, depending on the history of their prior responsiveness to C-/M-ECT and their Brief Psychiatric Rating Scale (BPRS) scores. At the third month, patients with biweekly ECT were assigned to receive either biweekly (n = 17) or triweekly ECT (n = 7) following the same criteria. The duration of Phase II was 6 months. Onset of illness, numbers of admission, educational level, duration of trials of the previously failed neuroleptics, BPRS scores, and percentage of reductions in BPRS scores at the end of Phase I, Global Assessment of Functioning (GAF) scores at the end of Phase I, Mini-Mental State Exam (MMSE) scores at Phase I entry and Phase I end, and GAF and MMSE scores during the first month of Phase II showed a differentiation between patients having weekly treatment versus biweekly treatment. Whereas a history of previously failed flupenthixol treatment, dosage of flupenthixol used in this study, and MMSE scores at the end of Phase I and during the first month of Phase II showed a differentiation between patients having biweekly C-ECT versus triweekly C-ECT. Our results suggest that the better the prognostic factors for each patient, the longer the frequency of C-ECT.