That's not particularly staggering, because the guy used to write poetry in between utterly decimating entire defenses, obliterating rushing records, running track and competing in the Winter Olympics. But it's proof that you can overcome mental illness in a big way, particularly since Walker is, by every account I've ever seen, an exceedingly good person as well as a phenomenal athlete.
By the way, the real reason I'm even posting this is to share my buddy Joe's comment on this:
Two personalities? Really? What are they, Badass and SuperDestroyer?