I am re-reading UNDER THE INFLUENCE by Milam and Ketcham and they discuss how the actual tissue cells and blood cells of the alcoholic actually are changed by alcohol abuse and these changes modify the physiology of the drinker's body. The changes actually demand more alcohol in order to stay off the effects of withdrawal. It's as though the body passes a point of no return, or at least a point of excruciating return.
The need for alcohol is in charge of the alcoholic and not the persons will or desires.
This is all more complex than any one theory of research study and but there seems to be some understanding in this book...for me. It helps me to cope and go on.