Well in my daughters case, I suspect she is slightly on the spectrum. Coped fine at home and in school; our home is very stable and, having four kids, we are quite hot on routines and being self reliant ans she went to a nurturing school with a big group of friends who had known her forever and had her back.
Uni was a competitive, back stabbing course, lots of group work with unreliable people, sharing a flat with people who were obsessed with image and being cool and who took lots of recreational drugs. Boyfriend graduated, couldn't get the amazing job he thought was his due and became really down. DD tends to mirror the people she is with.
By the end of second year in uni, my lovely vibrant feisty girl wasn't getting out of bed some days, let alone looking after herself properly. Her anxiety was causing debilitating IBS and bladder problems. She was an absolute wreck.
She had some counselling, did some reading, decided to sort herself out. She went to America to work in a kids camp for the summer. God knows how she motivated herself to do it. Spent three months running up mountains and swimming in lakes and eating healthy food. Three months with hardly ant screens or alcohol or drugs and surrounded by people doing positive things with their lives.
She came back like a different person, broke up with the gloomy boyfriend, ditched the bitchy friends. She's working hard and living more healthily and she's happy again.