ECT works by placing an electrode on one side of the head and a brief current is turned on. The current triggers seizures that will last about 1 minute, causing the body to convulse. In the past, ECT was not as safe; there was memory loss and broken bones, as the patents were not given muscle relaxers and anesthesia they are today. Today the World of Psychiatric Association has endorsed ECT as a safe and effective treatment especially for people with severe depression. The effects of ECT are not permanent and eventually those who were helped by ECT do need to return once of twice a year to receive treatments to keep their depression in check. Although ECT is effective with depression it is not effective with other disorders such as schizophrenia and alcoholism.
This article states that the importance of electrical dosage and electrode placement in relation to efficacy and side effects in uncertain. In a double-blind study, the psychologist randomly assigned 96 depressed patients to receive right unilateral or bilateral electroconvulsive therapy at either a low electrical dose. Symptoms of depression and cognitive functioning were assessed before, during and immediately after and two months after therapy. The patients who responded to the treatment were followed for one year to asses the rate of relapse. They found that the response rate for low-dose unilateral electroconvulsive therapy was 17% as compared with 43% percent for high dose unilateral therapy, 65% percent for low-dose bilateral therapy, and 63% for high dose bilateral therapy. They discovered that regardless of electrode placement, high dosage resulted in a more rapid improvement.
We can conclude that increasing the electrical dosage increases the efficacy of right unilateral electroconvulsive therapy, but not of bilateral electroconvulsive therapy.