Predictors of response to ultrabrief right unilateral electroconvulsive therapy

Recent trials have demonstrated clinically meaningful efficacy and minimal cognitive side effects with ultrabrief pulsewidth right unilateral (RUL) ECT. In many countries it is gradually being adopted into clinical practice and further information on predictors of response is needed.

Data collected from 75 depressed patients who received ultrabrief RUL ECT in a prospective research trial were analysed for predictors of response. Mood improvement was assessed with the Montgomery-Asberg Depression Rating Scale. Improvement in unipolar versus bipolar depression was analysed.

Sixty-one percent of patients met the criteria for response and 36% met the criteria for remission. Logistic regression identified index episode duration ≥one year (OR=10.50, p=.006), fewer failed antidepressant treatments (OR=0.46, p=.003), previous ECT course (OR=7.33, p=.01), and absence of concurrent antidepressant (OR=0.09, p=.005) as predictors of response. Psychotic features (OR=7.18, p=.032) and baseline depression severity (OR=0.90, p=.017) were predictors of remission. There was a trend towards greater improvement in bipolar than unipolar depression in the first week of treatment (p=0.077).

Data were obtained from a prospective but non-randomised clinical trial which was designed to evaluate efficacy rather than to examine predictors of response. Treatment decisions (concurrent medication, switching to other types of ECT) were made on clinical grounds.

This preliminary study suggests that predictors of response for ultrabrief RUL ECT are similar to those identified for other types of ECT previously studied.