> For an example, I have read writings of many experts in mental disorders that completely ignore changes in the DSM V.
Nitpick, but it's DSM 5; roman numerals were dropped after DSM IV.
> I do not know if the experts are not aware of the changes or don't agree with them
Almost certainly the latter. Lots of DSM V changes were, and are, controversial (even among people who acknowledge the existence of the problems the changes were intended to fix, the aisle solutions chosen are sometimes controversial.)
