How effective is it for eating disorders? Cognitive behavioural therapy is the treatment that has the most research behind it. There are other treatments that are variously effective as well, but not as well researched. I would say my reading of the literature is that probably, in terms of bulimia nervosa, about 50% of the patients get better through cognitive behavioural therapy or other treatments that have some evidence base to them. For anorexia nervosa, it's probably around 25% to 30%.
The evidence-based treatments are good, but they're not great in that sense, so there needs to be a lot more done in terms of researching more effective means of getting better outcomes for these patients.