Homosexuality was classified as a mental disorder in the Diagnostic and Statistical Manual of Mental Disorders (DSM) beginning with the first edition, published in 1952 by the American Psychiatric Association (APA). This classification was challenged by gay rights activists during the gay liberation following the 1969 Stonewall riots, and in December 1973, the APA board of trustees voted to declassify homosexuality as a mental disorder. In 1974, the DSM was updated and homosexuality was replaced with a new diagnostic code for individuals distressed by their homosexuality, termed ego-dystonic sexual orientation. Distress over one's sexual orientation remained in the manual, under different names, until the DSM-5 in 2013.