Background: electroconvulsive therapy (ECT) is the most effective treatment in treatment-resistant depression (TRD), but its response remains partial. Identifying useful indicators to guide decision making for treatment and improve clinical response remains a major issue. The objective of the present retrospective study was to determine if clinical response-early (after 5 ECT sessions) or longer-term (after 12 ECT sessions)-was associated with postictal suppression during the first ECT course and/or with postictal suppression frequency during the whole ECT course.
Methods: in a retrospective study, the data of 42 patients suffering from treatment-resistant depression and receiving at least 5 ECT sessions were collected. Two sessions per week of bitemporal brief-pulse ECT sessions were administered to patients. Each of the electroencephalography (EEG) recordings were assessed to determine the presence of postictal suppression.
Results: the postictal suppression from the first ECT session predicted a better long-term clinical response (after 12 ECT sessions), but not early clinical response (after only 5 ECT sessions). The postictal suppression frequency was associated with neither the short- nor the long-term clinical response. In addition, postictal suppression and short-term cognitive performances were not associated.
Conclusions: this EEG indicator is clinically useful if it appears in the first ECT sessions, but it is no longer relevant in the following sessions.
Keywords: electroconvulsive therapy (ECT); electroencephalography (EEG); postictal suppression; treatment-resistant depression (TRD).