The key factor in is therapy. Once a person has found a therapist she/he likes, this is often the start of a long process toward recovery. The duration of the eating disorder will certainly be the first determining factor: the shorter its history, the more likely and more quickly recovery is possible. For example, a 14-year-old who has been bulimic for under a year is more likely to benefit from therapy than a 30-year-old who has been bulimic since her college days. This doesn't mean that therapy would be ineffective for the 30-year-old, ....