Now, a controversial study published Tuesday in The Journal of Sexual Medicine suggests that it may be homophobia - not homosexuality itself - that has elements of a psychiatric disorder.
"After discussing for centuries if homosexuality is to be considered a disease, for the first time we demonstrated that the real disease to be cured is homophobia, associated with potentially severe psychopathologies," senior author Dr. Emmanuele Jannini, a professor of endocrinology and medical sexology at the University of Rome Tor Vergata, said in the press release.
Jannini and his team surveyed 551 university students to measure their levels of homophobia, defense mechanisms, attachment styles, and psychopathologic symptoms (symptoms that are linked to mental disorders).
While the study itself makes no mention of homophobia as a "disease," it did find some evidence supporting the idea that it may be, in part, pathological.
There's "a remarkable association between dysfunctional aspects of personality and homophobic attitude," the researchers write, concluding that psychoticism and immature defense mechanisms can predict to a certain extent whether people are homophobic. (Things like depressive symptoms, meanwhile, were more closely linked to the absence of homophobia.)
There are some important limitations to the study, however. First, any study done using a survey means the results rely on how people answer, which won't always perfectly reflect how they truly feel. This study, for example, could inadvertently be making conclusions about the people who are most forthcoming about their homophobia, rather than about all people who are actually homophobic. Second, all these conclusions are based on a very limited sample; it's highly likely that trends in the general population won't be the same as the trends found within a sample of 551 Italian students.
We must be careful not to extrapolate these results to the real world quite yet, Gregory M. Herek, a psychology professor at the University of California, Davis who has studied LGBT prejudice for decades and wasn't involved in this study, told Tech Insider. That's something he fears the media might try to do.
"We're not really talking about people who have a diagnosable mental illness, rather we're just talking about differences on a questionnaire," Herek said. "And the differences can be relatively small and not meaningful, and still be statistically significant."
In the study, the authors suggest that treating people who show signs of homophobia could be a way to reduce their prejudice toward LGBT individuals.
But Herek disagrees.
"To equate the two [mental illness and homophobia] I think actually steers us in the wrong direction," he told us, "because if you want to cure someone of a mental illness, you approach it very differently than if you're trying to change people's attitudes and get rid of prejudice conceived as a cultural or social phenomenon."
Jannini did not respond to a request for comment in time for publication.