There wasn't any that I know of from my math PhD program that wound up in a psychiatric ward - I might have been the craziest one, but I ended up ok in the end, largely on my resilience.

I left after 4 years, and in hindsight, I wish I left sooner. The wasted time did give me more of a sense of urgency in anything I do though, so that I do not end up regretting what I have done professionally.