That makes it a book in which some statements are social reflections rather than statements rooted in good science, which makes other such statements somewhat suspect.
It doesn't mean you should reject the whole thing out of hand but it might be a good idea to try to figure out how much of it is todays bias rather than good science in cases where that is warranted.
I'd contend that the most useful ground state for most of us, being people with no knowledge in the field whatsoever, is to assume that the DSM is broadly correct. From there you can, given some evidence, conclude that parts might not be.
