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.

Seizure threshold in ECT: I. Initial seizure threshold.

Seizure threshold determination is of crucial importance in optimizing electrical stimulus dosage during administering electroconvulsive therapy (ECT). We measured initial seizure threshold by means of Srinakharinwirot University titration schedule in 150 psychotic patients. Initial seizure threshold was approximately 104 millicoulombs on average, but varied widely (12-fold) across patients. Motor seizure duration was inversely related to initial seizure threshold. Seizure threshold could be strongly predicted by age. The results may have important clinical implications for stimulus dosing strategy in ECT.

Seizure threshold in ECT: II. Dose titration vs age and half age methods.

Seizure threshold determination is of crucial importance in optimizing electrical stimulus dosage at electroconvulsive therapy (ECT). We measured initial seizure threshold by means of Srinakharinwirot University titration schedule in 106 patients with schizophrenia or schizoaffective disorder, receiving bilateral ECT. Seizure threshold was approximately 106 millicoulombs on average, and varied 5-fold across patients. Seizure threshold was directly related to age, but inversely related to motor seizure duration. Comparisons of stimulus charge were done with the Age and Half age methods. By using the Half age method, 68 per cent of patients would have seized at the first stimulation and resulted in a closer mean charge to dose-titration method than the Age method. The results may have important clinical implications for stimulus dosing strategy in ECT.

The use of the stabilization period in electroconvulsive therapy research in schizophrenia: II. Implementation.

BACKGROUND: Electroconvulsive therapy (ECT) has been used to treat schizophrenia since its inception in 1938. Nonetheless, there has never been a research study documenting the efficacy of ECT in schizophrenia. All ECT studies suffered unexceptable methodological flaws. The authors hypothesized the 3-week stabilization period as: 1) a screening method for ECT responders, 2) a procedure for obtaining a homogeneous group of patients ideally suitable for the continuation treatment study, and, 3) as a part of our relapse criteria. METHOD: One hundred and fourteen schizophrenic patients received acute Phase I treatment with bilateral ECT and flupenthixol (12-24 mg/d). After the first sign of clinical improvement, all patients had to pass a 3-week stabilization period during which their clinical improvement had to be sustained. The patients had to receive at least 20 ECT treatments before being considered unresponsive to ECT. Fifty one patients enrolled in the continuation (Phase II) treatment study, and were randomized to the 3 treatment groups. RESULTS: In Phase I study, 58 patients were ECT responders by our criteria, 43 were nonresponders, and 13 were drop-outs. Forty five patients either relapsed or completed the Phase II study, while 6 patients dropped out. By our relapse criteria, 6 of 15 relapsed in the combined C-ECT and flupenthixol group, and 14 of 15 relapsed in both the group treated with C-ECT alone or flupenthixol alone. The use of the stabilization period in this study could complete all three objectives previously described. CONCLUSIONS: The use of the stabilization period is very useful in ECT research in schizophrenia.