I have a belief about PAWS that isn't orthodox. I'm throwing it out cause it might help, not to engage in controversy.
I believe a lot of reported PAWS isn't really post acute withdrawal syndrome. I think very often a person's compulsive substance use was masking or inadequately treating mood disorders or other psychiatric problems.
I also think sometimes, when people have used many substances for many years, the state of not using anything can be very uncomfortable for a while.
Another thing, if someone has been using continuously from their teens and now their in their late thirties, or later; you likely didn't feel your age when you were always on the hunt or high. Sober in the late thirties plus involves some realizations about aging you've been ignoring while using.
Anyways, not a complete critic of PAWS, but sometimes other situations are a better explanation, imo.