I have a friend. He has to be listening to music, watching television, reading some article online, chatting with people, and playing some video-game--all simultaneously, all the time--or he feels like his mind is collapsing in on him from the weight of all his thoughts and ideas and ambitions. He often gets drunk just so he can concentrate on only doing one thing--composing a song, say. Even when intensely interested in something--watching a movie with friends, say--he can't actually focus long enough to follow the plot. He ends up having to ask for a summary because he has no idea what happened.

And this is in his optimal environment, completely under his control.

He is not "thriving." He is cache-thrashing.