What is bears mental diagnosis/affliction that you believe he has?

I realized the third time watching the movie that the pills and behavior he exhibits might not be all deliberate but also signs of a mental health issue/disorder . It’s not said in the film but I can imagine he might have high functioning autism or possibly borderline personality disorder based on some of his behaviors echo that. If so, I kinda like that the director made the choice to be frankly honest with it and not try to have the story justify or relate to bears actions. What are your thoughts?