Seizure threshold in electroconvulsive therapy: III. A long-term study

There has been a dearth of long-term studies investigating the seizure-threshold changes in patients receiving electroconvulsive therapy (ECT). This study aimed to determine changes in seizure threshold over acute, continuation, and maintenance ECT (Phases I, II, and III). Twenty schizophrenic patients were estimated to have a seizure threshold by the dose-titration method. All patients had a rise in seizure threshold at the end of Phase I with 185 +/- 196 per cent increments. Ten patients had a further threshold-increase at the sixth month (Phase II, n = 20), and four at the twelfth month (Phase III, n = 14). The overall threshold-increases of Phases II and III were 370 +/- 342 per cent and 416 +/- 427 per cent, respectively. Seizure-threshold increases were robust during acute ECT, and tended to reach a plateau over the continuation and maintenance phases.