Is being trans a mental illness?

Let's start this series with one of the most common misconceptions

The American Psychological Association says that because trans people do not necessarily experience their cross-sex identity to be distressing or disabling, it does not meet the standard of a mental disorder. Under the Diagnostic and Statistical Manual of Mental Disorders, the current diagnosis for people who experience intense, persistent gender incongruence is "gender dysphoria," which is treatable. Gender dysphoria is described as a "marked incongruence between their experienced or expressed gender and the one they were assigned at birth.”  

Trans people are not a new concept. Trans people have been described throughout history, with ancient Greek and Roman writings describing people who changed their gender. The Roman emperor Elagabalus offered large sums of money to any doctor willing to perform sexual reassignment surgery. In the modern era, the first gender confirmation surgery was performed in 1952.

Although there are many potential hypotheses, it is currently unknown what causes people to have a transgender identity. One study suggested that brain differences between trans women and cisgender men exist prior to medical transition, but its sample size was small, and existing research shows no link between believing that an identity is innate and acceptance for the group with that identity.

Trans people do, however, experience higher rates of mental health disorders related to societal rejection and mistreatment, including depression, anxiety, and substance abuse disorder — which is all the more reason to end the stigma around trans identity. After all, there is no mental illness whose cure is bullying or harassment.