A study into predictors for the speed of response to electroconvulsive therapy.

The efficacy of electroconvulsive therapy (ECT) has been firmly established in the treatment of depression. However, prediction of the speed of response to ECT is an issue that needs to be further explored. This study aims to examine the presence of predictors for the speed of response. In a retrospective chart review using 57 patients suffering from major depression who received ECT, the relation of several patient and ECT variables with the speed of response was explored. Response was defined as a drop of at least 35% in Hamilton rating scale of depression (HRSD) score from baseline after 3 or 4 ECT sessions. Patients received ECT with an aged-based stimulus dosage in a clinical setting. Multiple regression analysis showed that high baseline HRSD score and high seizure energy index (SEI) were significantly and independently associated with a rapid response. In a regression model, baseline HRSD score and SEI can be used to predict the speed of response to ECT. Rapid responders to ECT achieved remission significantly more often than slow responders did. SEI can be modified by the clinician. This offers the possibility to optimize ECT treatment.