Electroconvulsive therapy (ECT) has been used to treat mental disorders for more than 70 years, but it remains a controversial therapy. Opinions about ECT vary widely, with some researchers considering it to be a safe and effective therapy and others considering it to be an ineffective treatment that causes brain damage. The United Kingdom ECT Review Group conducted a systematic review of scientific and medical databases to evaluate the potential benefits and harms of ECT in the treatment of depression.

The group searched the databases to identify randomized controlled trials (RCTs) of ECT in the treatment of depression, including studies comparing ECT with pharmacotherapy and studies comparing different forms of ECT. Each of the 624 reports reviewed was independently assessed for quality by two reviewers. Data were extracted from 73 RCTs that met quality criteria to assess the efficacy of ECT on symptom relief and the incidence of adverse effects on cognitive function and mortality. The review included a search for evidence of structural brain changes reported in studies that included neuroimaging or postmortem examination of the brain.

Six trials, with a total of 256 patients, compared ECT with simulated procedures in which all components of ECT, including anesthesia, were given but no electrical current was passed. These trials were conducted before 1985, and the largest one included 70 patients. Real ECT was significantly more effective than the simulated procedure, with an estimated gain of 9.7 points on the Hamilton Depression Rating Scale. The duration of benefit is uncertain because the only study that reported a depression score six months after ECT found a nonsignificant difference of 2 points in the simulated ECT group. Compared with the patients who received simulated ECT, those who received real ECT had no differences at six months in memory, ability to learn, or real memory.

In 18 trials with a total of 1,144 patients, ECT was compared with a variety of pharmacotherapeutic agents. In four trials, patients were eligible for randomization only after failing to respond to one or more antidepressant medications. The trials ranged in duration from three to 12 weeks. Overall, fewer patients discontinued ECT than drug therapy for depression. In all but two trials, ECT was more effective than medication in treating depressive symptoms. In the pooled data, the difference was significant, equivalent to a mean difference of 5.2 points on the depression scale. The two trials that assessed cognitive function reported conflicting results. One trial reported no difference in cognitive function between patients treated with ECT and those taking medications, whereas another trial reported more subjective memory loss in patients treated with ECT.

Based on the randomized evidence, the authors conclude that ECT is a consistently effective short-term treatment for depression in selected adult patients. They caution that most evidence is based on older studies, each involving small numbers of patients and, in most instances, comparisons of ECT with older medications. Nevertheless, they find evidence that ECT remains an important option in the treatment of severe depression.

editor's note: Like many physicians of a certain age, I admit to a bias against ECT based on attending sessions during my student and intern days, caring for patients during the postictal period, and worrying about the irreversibility of the treatments. This study leaves us with the uncomfortable feeling that ECT may be underused, but it provides little guidance as to which patients could benefit. As the authors point out, most of the studies in this meta-analysis are older than 10 years and compare ECT with tricyclic antidepressant therapy. Would we be able to conduct updated trials of ECT against the newer antidepressant agents? The trials could not be completely blinded. Valid informed consent is problematic in most psychiatric conditions, and giving anesthesia for “mock ECT” raises all kinds of ethical issues about risk to patients. The situation is further complicated by local factors. ECT should be given by an experienced team, and because its use has declined, family physicians could have difficulty finding psychiatric colleagues with the appropriate expertise. Perhaps the optimal role for ECT is in combination with antidepressant medications rather than as an alternative. Given all the problems over studies, we may never know.—a.d.w.