Graduation rates at upper tier schools are very high and suicide rates among young adults in college are no higher and I would venture to guess a tad lower than the general population.
Whether or not someone thrives or fails at the most upper tier schools or the very lowest tier has less to do with the school and more to do with the person/student. Some students will squander and fail in the most enriched supportive college with every advantage available, while another student will scrape, claw, fight and succeed while starting at the lowest ranked struggling institution.