It has been said that she is having a breakdown of some kind. There is allegedly a spiritual element to it, I don't think it has much to do with cults though [english.pravda.ru]
Its probably that they were going to test her hair follicles for drug use, which could explain her cutting the hair off, when added with psychosis from extended hard drug use.
But now that she is out of rehab, you can be certain that all of the big hollywood cults are trying to recruit her. Tom Cruise and Travolta for Scientology, and Madonna for Kabbalah, and whoever else can get their hands on her. Someone who is vulnerable like her would be an extremely desired target for those cults, and once they can get her converted and promoting the group, she could bring in lots of young women.
My guess is it will be about a month until Britney starts promoting one of those hollywood cults, probably that fake Kabbalah through Madonna.