During the ECT procedure, a small amount of electrical current is passed to the brain. This current induces a generalized grand mal seizure affecting brain centers that control mood, appetite, and sleep. ECT is believed to correct the biochemical abnormalities that underlie severe depressive illness. To elicit a seizure alone is not sufficient for the desired therapeutic effect. A combination of factors, including electrode placement and stimulus dosage, are fundamental to achieving the effective therapeutic response.