Effect of antidepressant medication resistance on short-term response to electroconvulsive therapy

This prospective study assessed the influence of resistance to antidepressant pharmacotherapy on the short-term response to subsequent electroconvulsive therapy (ECT). Previous research has shown that patients with medication resistance were less likely to respond to ECT. This finding may be applicable to the population of depressed inpatients in The Netherlands, where ECT is often preceded by several medication trials. Eighty-five patients (61 female and 24 male patients) with DSM-IV criteria for depressive disorder, both with and without mood congruent psychotic features, were included for analysis. Medication resistance was rated with the Antidepressant Treatment History Form. Medication resistance was predefined in accordance with the previous research in this field. When a reduction of at least 50% on the 17-item version of the Hamilton Rating Scale for Depression (HRSD) between pre- and post-ECT is used as response criterion, medication-resistant patients were equally likely to respond to subsequent ECT (30/48 = 82.5%) than patients without medication resistance (30/37 = 81.1%). Even when post-ECT HRSD score < or = 7 was used (full remission), there was no significant difference between medication-resistant patients (21/48 = 43.8%) and patients without medication resistance (15/37 = 40.5%). When potential confounding variables were taken into account, these differences remain nonsignificant. In contrast to earlier research, medication resistance does not influence short-term response to subsequent ECT and it can still be of considerable efficacy.