Since the third edition of DSM, the diagnostic system has changed to focus on observable behavior where clusters of symptoms with a common course, predictable pattern of changes across time, constitute a diagnosis.  Whether clinicians should even be labeling individuals as having a diagnosis is heavily debated in the field because of the impact of that label on the person’s future behavior and adjustment, especially given the flaws in diagnostic system and how the view of mental illness changes. 

            Homosexuality is a striking example of change in perspective. Scientists, church officials, and the general public debate whether genetics and physical differences underlie homosexuality, but few would characterize it as a mental illness today.  In the second edition of DSM, published in 1968, homosexuality was a diagnostic category, a definable mental illness. 

             In the third edition of DSM, this was softened by having a category called “ego dystonic homosexuality,” characterized by a person experiencing extreme distress due to his/her homosexual tendencies.