I don't think he was ever that good in the head. The first time I saw him was at Arsenal in the 2012/2013 season, he was great that night. Created decent chances, pretty much constantly turned their players and put a few good through balls in. In Bobby's first season, he was great especially at the start of the season, just running at teams and having shots. The problem was he never really developed the skills other players like Arteta, Pienaar even players like Felaini and Bernard now, the ability to keep the ball and make passes and hold the ball at the same time. I remember when we played Arsenal in the cup and he somehow managed to blast the ball over the ball over the bar from like 7 yards out, when he could of just placed it in the bottom corner.
He wasn't that bad in the next 2 seasons, but he certainly didn't develop that much. In the 2016/2017 season I just gave up with him, he needed about 5 seconds to turn with the ball. The amount of time, he just stopped with the ball, when he could of turned and run at goal and made a shot. Going to bars that most normal people, wouldn't go to right after games and getting punched is hardly sensible either. My view is that there was always something off with Barkley, while I wouldn't diagnose him with depression or something, I do think there was something going on behind the scenes, that affected his performances. I think sometimes we falsely assume players have large amount of self confidence I don't think Barkley did. I think quality players either need to be calm, smart or aggressive, Barkley is none of those things.