Brown was a headcase pre-Burfict Hit so you can't blame it all on that. That being said, it does seem to have been amplified since then so I wouldn't be surprised if it had something to do with it. Just sad to watch.
This guy has had a reputation since high school. Got in fights, got expelled. Hates authority. Horrible grades. Finally got into Central Michigan of all places, got pampered there. Wasn't on a lot of teams draft boards. There's a reason that he lasted until the 6th round after dominating in the MAC.
I'm a Steelers fan and I remember reading about how much of a hard worker he was early on but he was described as aloof and flaky, an odd duck. After he became a #1 receiver and got his 2nd contract the trouble began. I give credit to Tomlin's coaching and the talent and sheer assholery of Ben Roethlisberger for keeping AB somewhat in line. But a lot of BS was covered up until finally, with the playoffs on the line AB just up and quit the team.
Then there's all of the people who worked for AB who never got paid-- managers, agents, electricians, massage therapists (apparently AB thought that just the opportunity to work on him and get groped by him was pay enough). AB doesn't want to pay anyone yet he will loose it if he thinks he is not getting his due. Someone is always out to get him. He was on the verge of getting a million dollars in incentive bonuses and would have made it. But I bet yesterday's eruption was over his concern that he wasn't getting enough targets and that Brady and the Bucs wanted to keep him from getting "his money".
The concussions could be playing a role, but he's always been a narcissist, probably a psychopath and bipolar. And a first class turd.