I can only speak for me, but I also have an eating disorder and I binge eat. As a child I could only by sugar and food. I ate to numb the pain. Even today I use food to numb the pain so I don't have to deal with emotional pain.
I can be really determined not to binge eat, but I do it. It is like I can't control myself. I have been learning to try and find out the feeling I am feeling that I haven't yet dealt with so I can deal with it. I am hoping that ptsd therapy will help me in dealing with not only my eating disorder but all the emotional baggage I suffer because of the many years of abuse.
Maybe it is the same with others who have other additions to cover up their emotional pain.
Love and Blessings
Chrisy