The use of electroconvulsive therapy (ECT) to treat depression should be immediately suspended, a study says.
ECT involves passing electric currents through a patient's brain to cause seizures or fits.
Dr. John Read, of the University of East London, said there was "no place" for ECT in evidence-based medicine due to risks of brain damage.
But the Royal College of Psychiatrists said ECT offers "life-saving treatment" and should continue in severe cases.
At least 1,600 patients were given ECT in the UK and Ireland in 2017, according to psychiatrists.
The National Institute for Health and Care Excellence (NICE) currently recommends the use of ECT for some cases of moderate or severe depression as well as catatonia and mania.
However, peer-reviewed research published in the journal Ethical Human Psychology and Psychiatry concludes "the high risk of permanent memory loss and the small mortality risk means that its use should be immediately suspended".
NICE says their guidance for ECT was last reviewed in 2014 but it would look at it again if new evidence was likely to affect their recommendations.
The study's lead author, Dr. Read, a professor of clinical psychology, describes previous research justifying the use of ECT in the UK and around the world as "the lowest quality of any I have seen in my 40-year career".
The paper concedes that "the severity and significance of the brain damage and memory loss (following ECT) is rarely studied".
However, the researchers go on to say "it is not hard to find hundreds of personal accounts of debilitating levels of disruption to people's lives".
In 2018, a class action case was settled in the US after a federal court ruled that a reasonable jury could find against manufacturers of ECT equipment if they failed to warn of the dangers of brain damage.
One manufacturer, Somatics, immediately added "permanent brain damage" to the list of risks from the treatment.
The research criticizes a British review of the evidence conducted in 2003 for ignoring the lack of data.
The UK ECT Review Group "fails to acknowledge any of these major problems and unquestioningly included the strong finding in favor of ECT", it says.
The article argues the quality of previous studies into ECT is so poor, they "were wrong to conclude anything about efficacy, either during or beyond the treatment period".
"There is no evidence that ECT is effective for its target demographic—older women, or its target diagnostic group—severely depressed people, or for suicidal people, people who have unsuccessfully tried other treatments first, involuntary patients, or children and adolescent", it says.
The paper suggests the placebo effect may explain why some patients say they find ECT helpful.
The study's joint author, Prof Irving Kirsch, an expert on placebo effects based at Harvard Medical School, says "the failure to find any meaningful benefits in long-term benefits compared to placebo groups are particularly distressing.
"On the basis of the clinical trial data, ECT should not be used for depressed individuals."
In response to the study, the Royal College of Psychiatrists said ECT should not be suspended for "some forms of severe mental illness".
Dr. Rupert McShane, chair of the college's Committee on ECT and Related Treatments, said there was evidence showing "most people who receive ECT see an improvement in their condition".
"For many, it can be a life-saving treatment," he said.
"As with all treatments for serious medical conditions - from cancer to heart disease -, there can be side-effects of differing severity, including memory loss."