The current DSM is no better. It, too, reflects a not-so-subtle liberal bias. The definition of pedophilia, for example, has been changed substantially. While the old definition stated that you had to be at least 16 years of age and had to molest a child to be diagnosed with pedophilia, the new definition states that you must be 18 years old and molest "two or more different children." That's right -- pedophiles now get one freebie before being diagnosed with pedophilia. If this isn't defining deviancy down, it's difficult to see what would be.
On a similar note, the DSM has redefined gender identity disorder (GID) -- or rather, they've renamed it. Gender identity disorder is a mental condition where members of one sex think they're in the wrong bodies. The DSM now calls this condition "gender incongruity," explaining that the new term "better reflects the core of the problem: an incongruence between, on the one hand, what identity one experiences and/or expresses and, on the other hand, how one is expected to live based on one's assigned gender."
Clearly, this is propaganda -- gender is not assigned at birth. It is assigned with biology; as scientific studies have amply shown, males and females have significant differences in brain biology. But the DSM isn't concerned with actual science -- they're more concerned with the issue that "many [transgendered people] very clearly indicated their rejection of the GID term because, in their view, it contributes to the stigmatization of their condition." This is inane. Sufferers of a condition do not get to rename that condition at will to spare their feelings. Otherwise, kleptomaniacs would be able to call themselves "friendly borrowers."
The left consistently argues that the right wants to shut down science. But when the left has an agenda, it ignores science at will, whether with regard to global warming, abortion or mental health. Psychology is a young and still-evolving field, but the more it subjects itself to the whims of political actors, the less legitimate it will be.