What an interesting discussion!
Mental disorders are one of my favorite things to think about with my version, I’m actually going to make that the next subject of my Werewolf Guide whenever I get around to drawing the next picture for it.
My wolves don’t have it easy in the mental illness department. If bitten they keep any problems they had while human. The best changing can do for them is reduce the likelihood of coming down with some genetic problems that are partially environmentally based. If the problem is purely genetic or you are already pretty far along by the time you get changed you’re out of luck. Interestingly enough there are some built in “safety devices,” for lack of a better way to describe it. It is not unheard of for a werewolf with severe mental illness or trauma that is causing erratic behavior to suddenly shut down mentally or even commit suicide. I’m still not sure how this would work out, but I imagine it could be a kind of “survival of the fittest” thing that has been bred into them over the centuries, or perhaps something that has always been an element of their condition. Much of their behavior can change radically when they get into situations where they risk exposing themselves and their whole race to humankind (my only way of imagining a decently sized werewolf population living alongside humans for all these years without being noticed. This is one of the things I struggle with the most when trying to make is sound at least halfway realistic). Without knowing it, they sometimes alter their behavior in ways that are destructive to themselves but beneficial to their entire race. The idea definitely works better when thinking of it as a magically based condition that may at some time in the distant past been designed to give them the ability to adapt to their environment on a non-genetic level. This of course doesn’t help with the ones who actively chose to kill or expose themselves and cause problems for everybody else- people like that are usually taken care of by others in the werewolf community who are focused on keeping a low profile. Good old vigilante justice.
To make things more difficult for them they are more susceptible to some mental disorders than humans. Many of those are anxiety based and are things that bother them at the level of their animal instincts. Claustrophobia for example is more common in werewolves than humans, they sometimes panic at the feeling of being caged or cornered. Some werewolves actually use this to their advantage by creating psychological torture devices for their enemies, since many werewolves have a very high threshold for physical pain.
And then there are mental disorders that are completely unique to them. One I have come up with is Shapeshifting Maladjustment Syndrome, which is a rare disorder where for some unknown reason the werewolf cannot keep the normal balance between human and wolf instincts. Human instincts are supposed to be dominant if the werewolf is trying to live alongside humans, even while in wolf form. I did this to one of my first characters. He started out after being bitten as a normal werewolf with full control over himself, but over the next few years became confused and increasingly more aggressive and fearful in everyday situations. He ended up killing several people, then feeling guilty about it and turning himself in to the police. He swore that he could change himself into a wolf but refused to show anyone, and before the courts could sort through the whole mess he killed himself. Poor Erick.