Discusses the outcome of electroconvulsive shock therapy (ECT) in 12 patients (aged 46-76 yrs) with resistant depression. Eight Ss had been refractory to a clinically adequate course of ECT (Hamilton Rating Scale for Depresion improvement <20%) and 4 were partial responders (improvement 20-49%). All Ss remitted completely on antidepressant medication within a mean of 2.2 mo of the ECT course. Remission was associated with clomipramine treatment in 7 cases and maprotiline in 1 case. Four Ss who did not respond to a tricyclic antidepressant alone remitted following supplementation with lithium carbonate. Results suggest that ECT may alter the sensitivity of refractory patients to antidepressant medication.