We had mutual friends and I met him a few times. He had his own "darkness" just like Bill Zeller.
I do wonder if places like Princeton bring out the darkness in people there. I enjoyed my time there but spent the last year of it in and out of counseling and more depressed than I ever hope to be again.
There were some good counselors there in the health center who were kind and patient. It's too bad Bill wasn't able to connect with one of them.
A lot of the problem is with the town. The "town" of Princeton is a sham propped up to impress visiting students. There's really not a whole lot there. Meanwhile, students are required to live in dorms all 4 years, which gives them a really artificial "home life" that doesn't help ground you very much either.
I lived and worked in the town of Princeton for two years after graduation and it was a thoroughly depressing and isolating experience. Unless you're a member of the university community, there's just nothing there to get excited about. You have to leave on the train for the day to do anything interesting.