A sixth of British therapists said they had tried to help gay, bisexual and lesbian patients become heterosexual, even though evidence suggests such therapies can be harmful, according to a survey released on Thursday.
Michael King of University College London, who published his findings in the journal BMC Pyschiatry, said the number of therapists who said they had tried to help a person change their sexual orientation was surprising.
"There is very little evidence to show that attempting to treat a person's homosexual feelings is effective and in fact it can actually be harmful," King said in a telephone interview. Such an approach could provoke greater anxiety and confusion.
The survey showed that 17 percent of therapists and psychiatrists working in Britain had sought to help their patients reduce "gay or lesbian feelings" through therapy, the researchers said.
Treating homosexuality as a mental illness was more common in the United States and Britain during the 1970s and 1980s, when so-called "aversion" therapy was in vogue, he added.
These treatments involved tactics such as pairing homosexual imagery with electric shocks to induce feelings of revulsion, King said.
The World Health Organization only removed homosexuality from its list of mental illnesses in 1992, he added
"There was a huge fashion for these treatments in the 1970s and 80s," he said. "Now we are talking more about helping patients control their thoughts, to reduce their homosexual feelings."
King's study showed that some therapists now use more subtle strategies aimed at getting patients to "control" their homosexual feelings, and eventually change their sexual orientation.
King and colleagues asked more than 1,400 therapists if they would try to change a patient's sexual orientation if asked to do so.
Only 4 percent declared that they would. However, in response to further questions, one in six said that they had already tried to help patients control or change their sexual orientation through a range of therapies.
Reasons provided by therapists in the anonymous study ranged from their own religious and moral views about homosexuality to patients' anxiety over discrimination, the researchers said.