I find it highly believable as well.
When I finally quit my D1 team after 3 stress fractures, I felt sad, but at the same time liberated. With no practices to worry about, I experimented. I remember staying up all night, working extremely long hours on projects that fascinated me in my major- hanging out with other kids at the lab. It felt so good to have my hours free to interact with non-runners, and staying up all night, not worrying about a bedtime, felt exciting.
I also smoked pot for the first time about a week after quitting the team- also with kids from my major. It hardly sounds rebellious, but I had had an extremely regimented lifestyle due to my running goals for many years. Unlike the author's experience with the cigarette, I found smoking pot the first time to be exhilarating and strangely life affirming. It sounds cheesy, but I finally felt free.
Also, I echo what so, so many other posters have said: this blog hits on so very many things I experienced as a female at a competitive D1 school.