People with severe depression may be better off having electric shock therapy than taking medication, a study suggests.
ECT is only used on patients with severe depression
Researchers at Oxford University say there is strong evidence that the controversial treatment may be more effective than drugs.
Electroconvulsive therapy (ECT) has been used by psychiatrists since the 1930s. However, some groups have criticised its use saying there is little evidence it works and not enough is known about its long-term effects.
There has also been criticism of the fact that the therapy is often used on patients who are unable to give their consent.
ECT involves placing electrodes on the temples, on one or both sides of the patient's head, and delivering a small electrical current. This aims to shock the brain and to restore its natural chemical balance.
Professor John Geddes and colleagues at Oxford University reviewed more than 73 trials of ECT carried out over the past 40 years.
In the short-term ECT reduces depressive symptoms and it may be a bit better than drugs
These included studies comparing ECT with a dummy electric shock, others comparing the therapy with anti-depressants and others comparing different doses of ECT.
The researchers found that ECT was more effective at reducing the symptoms of patients than a dummy electric shock.
Similarly, the therapy was also more effective at reducing depression than medical drugs.
Writing in the medical journal The Lancet, the researchers said the study provided evidence that ECT works.
"There is a reasonable evidence base for the use of ECT: it does not rest simply on anecdote, habit and tradition," they wrote.
"Although many of the trials are old, and most were small, the randomised evidence consistently shows that in the short-term, ECT is an effective treatment for adult patients with depressive disorders."
Speaking to BBC News Online, Professor Geddes said the study, which was funded by the UK government, is one of the first to review all of the research relating to ECT.
"This is a review of all the available evidence on ECT," he said. "We found that in the short-term ECT reduces depressive symptoms and that it may be a bit better than drugs."
"This is the first time all of the available evidence has been reviewed. We hope our study will enable patients and clinicians to make an informed decision on treatment."
Officials at the mental health strategy Sane welcomed the study.
Margaret Edwards, its head of strategy, said: "ECT can have a beneficial effect and in some cases be life- saving. We are aware that some people experience short-term memory loss and other side effects, but as with any treatment the risks must be balanced against the benefits.
"We believe that individuals should be able to have the choice to refuse ECT or - if it is recommended - to have it, provided they are made aware of the possible side effects and the treatment is administered in full compliance with clinical guidelines.
"It is important to have this validated evidence of the effectiveness of ECT in treating depression. We hope that - as flagged by the authors of the paper - it will be used as a base for formulating national policies and standards in staff training, skills, and information to patients."