The efficacy of electroconvulsive therapy (ECT) in the treatment of affective disorders is well established. Despite its clinical utility, there is no generally accepted theory regarding its mode of action. Several lines of evidence indicate that ECT has significant anticonvulsant properties and results in decreased neural metabolic activity. We suggest that these effects are due to enhanced gamma-aminobutyric acid (GABA) transmission and that localized suppression of neural metabolic activity is associated with therapeutic response to ECT. An implication of this view is that ECT may be a useful adjunctive treatment in intractable epilepsy.