For a fiction novel, would like to describe the physical and mental symptoms of the character having a psychotic break/mental breakdown, when they're so overwhelmed, do they do other things that is normally out of character.
Instead of writing, "he had a psychotic break", would like to describe the actual symptoms to make it more realistic and hopefully believable. What would an outside observer see? The guy's eye twitching? Rapid breathing? What would go on in his mind? Any guidance is greatly appreciated!