It's obvious that none of really know about his mental health issues.
However his history when at City, and the way he dealt with the club when trying to get him to sign the contract, suggests that he has a very high opinion of his ability, and didn't want to listen to people with more experience in the game.
He comes across as a bit of a big-headed individual who believes the hype he got when at Dortmund, whilst his games for England and the rags suggest that his opinion doesn't match his performances.
He took the rag's money and has proved to be , for whatever reasons, an unmitigated disaster football wise.
For what it is worth, my opinion is that he is arrogant and conceited, clearly believing he is much better than he really is, and has been found out even by the fucking useless rag management team.
Which is some damning indictment of his time at the swamp.