Can any generalisations be made about the psychological reasons for why some people are anorexic whilst others are bulimic?

I’m interested in what might be termed a tipping point for going in one direction or the other in terms of these eating disorders i.e. why someone might develop an eating disorder such as anorexia that denies food intake, whilst others that develop bulimia or compulsive eating disorders develop over-eating.

What if any psychological characteristics can determine which way the disorder develops? It occurs to me, although I could be wrong , (please point this out if I am!) that those that have anorexia are unlikely, if ever, to develop bulimia or vice versa and that these coping mechanisms for dealing with food, weight issues and other psychological problems are laid down as such (perhaps wired in the brain?), thereby implying that there are distinct differences between the two on a biological and psychological level.

Hope that makes some sense….I have struggled somewhat to put it into words. Let me know if it’s not clear enough!