The research, published in The Lancet Psychiatry journal today and led by the National Institute of Psychiatry Ramón de le Fuente Muñiz, involved interviewing 250 transgender people and found that distress and dysfunction were more strongly predicted by experiences of social rejection and violence than by gender incongruence itself. The study is the first of several field trials and is currently being replicated in Brazil, France, India, Lebanon and South Africa.
"Stigma associated with both mental disorder and transgender identity has contributed to the precarious legal status, human rights violations and barriers to appropriate care among transgender people," says senior author Professor Geoffrey Reed, National Autonomous University of Mexico. "The definition of transgender identity as a mental disorder has been misused to justify denial of health care and contributed to the perception that transgender people must be treated by psychiatric specialists, creating barriers to health care services. The definition has even been misused by some governments to deny self-determination and decision-making authority to transgender people in matters ranging from changing legal documents to child custody and reproduction." 
"Our findings support the idea that distress and dysfunction may be the result of stigmatization and maltreatment, rather than integral aspects of transgender identity," says lead investigator Dr Rebeca Robles, Mexican National Institute of Psychiatry. "The next step is to confirm this in further studies in different countries, ahead of the approval of the WHO revision to International Classification of Diseases in 2018." 
Transgender identity is currently classified as a mental disorder in both of the world's main diagnostic manuals, the WHO's ICD-10 and the American Psychiatric Association's DSM-5. A major component of the definition of mental disorders is that they are associated with distress and impairment in functioning. The classification of transgender identity as a mental disorder is increasingly controversial and a WHO Working Group has recommended that transgender identity should no longer be classified as a mental disorder in ICD-11, but should instead come under a new chapter on conditions related to sexual health.
The study is the first field trial to evaluate the applicability of the proposed re-classification. It was conducted in collaboration with the Condesa Specialized Clinic, the only publicly funded specialized clinic providing transgender health care services in Mexico City. Researchers interviewed 250 transgender people aged 18-65 who were receiving health care services at the Condesa Clinic. Most participants were transgender women, assigned male sex at birth (199 participants, 80%).
Participants reported first becoming aware of their transgender identity during childhood or adolescence (ages 2-17) (table 1). During the study, they completed a detailed interview about their experience of gender incongruence in adolescence (e.g, discomfort with secondary sex characteristics, changes performed to be more similar to the desired gender, and asking to be referred to as the desired gender), and recalled related experiences of psychological distress, functional impairment, social rejection and violence.
Most participants experienced psychological distress related to gender incongruence during their adolescence (208, 83%), with depressive symptoms being the most common. Family, social, or work or academic dysfunction during adolescence related to their gender identity was reported by nearly all participants (226, 90%).
More than three-quarters of participants (191, 76%) reported experiencing social rejection related to gender incongruence, most commonly by family members, followed by schoolmates/co-workers and friends. A majority of participants (157, 63%) had been a victim of violence related to their gender identity (table 3) - in nearly half of these cases, violence was perpetrated by a family member. Psychological and physical violence were the most commonly reported, and some experienced sexual violence.
The researchers then used statistical models to examine whether distress was related to gender incongruence per se or if it was related to experiences of social rejection and violence. They found that none of the gender incongruence variables predicted psychological distress or dysfunction, except in one case where asking to be referred to as the desired gender predicted school/work dysfunction. On the other hand, social rejection and violence were strong predictors of distress and all types of dysfunction (table 4).
Although the study includes a relatively large sample of transgender people, the authors warn of some important limitations. For example, the study was a volunteer sample, so was not representative of the population and participants' experiences were based on their recollection of events, which can be subject to bias. However, the authors note that a similar study would be difficult to conduct prospectively as this would involve children.
"Rates of experiences related to social rejection and violence were extremely high in this study, and the frequency with which this occurred within participants own families is particularly disturbing. Unfortunately, the level of maltreatment experienced in this sample is consistent with other studies from around the world. This study highlights the need for policies and programs to reduce stigmatization and victimization of this population. The removal of transgender diagnoses from the classification of mental disorders can be a useful part of those efforts," says Dr Robles. 
Writing in a linked Comment, Dr Griet De Cuypere, University Hospital, Ghent, Belgium and Dr Sam Winter, Curtin University, Perth, WA, Australia, say: "A prominent UN advocate has put it this way: 'Transphobia is a health issue'. This study prompts primary caregivers and psychiatrists to be aware of a 'slope leading from stigma to sickness' for transgender individuals, and to contribute to their mental health by a gender-affirmative approach." They also note that although the study provides evidence to support moving health-related categories related to transgender identity out of the classification of mental disorders in ICD-11, it does not address where in ICD would be the most appropriate place for the diagnosis, which should be a topic for future research.
NOTE TO EDITORS:
The study was funded by the National Institute of Psychiatry "Ramón de la Fuente Muñiz", Mexico.
 Quote direct from authors and cannot be found in text of Article.
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