Nearly 200,000 transgender people in the United States have been exposed to so-called conversion therapy at some point in their lives, according to a study published Thursday by The American Journal of Public Health.

“Conversion therapy” refers to efforts to change an LGBTQ person’s gender identity or sexual orientation and has been condemned by nearly every major health association, including the American Medical Association, the American Psychological Association and the American Academy of Pediatrics.

Using data from the National Center for Transgender Equality’s 2015 U.S. Transgender Survey and UCLA's Williams Institute, researchers from Harvard and The Fenway Institute estimated that 187,923 trans people across all 50 states — or approximately 13.5 percent of the country’s estimated 1.4 million self-identified trans individuals — have been subjected to attempts to change their gender identity by a “professional,” such as a psychologist, counselor or religious adviser.

“Our research team was extremely concerned to find that this practice, which is widely discredited by major medical organizations, was so prevalent,” Dr. Jack Turban, a resident physician in psychiatry at Harvard Medical School and the study’s lead author, told NBC News in an email.

The researchers broke down the data in several ways, including by state. Respondents in Wyoming, South Dakota and Montana were the most likely to experience gender conversion therapy in their lifetime, with more than 20 percent of respondents in each state reporting they had experienced gender conversion therapy methods.

In addition to examining lifetime exposure of psychological attempts to change a person’s gender identity from transgender to cisgender (PACGI), researchers also examined exposure to such conversion efforts from 2010-15, “to capture the diagnostic change from ‘gender identity disorder’ to ‘gender dysphoria’” by the American Psychiatric Association.

Gender identity disorder was historically used by mental health professionals to diagnose trans individuals despite objections from advocates, who argued that the term further stigmatized trans people by assigning them a lifelong mental health diagnosis. Gender dysphoria, which is used to describe the emotional distress over “a marked incongruence between one’s experienced/expressed gender and assigned gender,” has been deemed the more accurate terminology by the APA since 2010.

Researchers found that 5 percent of trans people reported exposure to conversion therapy from 2010 to 2015. The number of individuals varied across states, but similar to the lifetime exposure results, respondents from South Dakota (16.3 percent) and Wyoming (9.1 percent) were the most likely to experience gender conversion therapy at some point during this five-year period.

Most major medical organizations, including the American Medical Association, have labeled gender identity conversion efforts as unethical and state that they can lead to adverse mental health outcomes.

Trans individuals suffer elevated risks of anxiety and depression compared with the general U.S. population, according to experts. In an earlier study, Turban looked at such mental health outcomes for transgender individuals and determined that exposure to conversion therapy is “associated with severe mental distress, suicide ideation and suicide attempts.”

Turban said he hopes his findings will highlight the magnitude of this controversial practice for state legislators who are considering legislation to ban the practice on minors.

“In the past, some state legislators have argued that such bans are not necessary because gender identity change efforts do not occur in their state,” Turban said.

He cited as an example former Maine Gov. Paul LePage, who vetoed a 2018 bill to ban conversion therapy in the state because he said there was “no evidence” that the practice was employed.

“Our findings show that this is false,” Turban said. “Transgender people in every U.S. state reported exposure to gender identity change efforts.”

In the last 30 months, 13 laws have been passed protecting minors against conversion therapy. Currently 18 states, along with the District of Columbia, ban the practice on minors.

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