Bulimia: From Impulsive to Compulsive Behavior

What is Bulimia?
Bulimia Nervosa (BN) is an eating disorder characterized by a period of binge eating followed by a period of purging. Binge eating is defined as eating a lot of food in very little time. Purging is the attempt to get rid of that food. The most common form of purging is vomiting
Impulsive Behavior 
There are many situations in which humans make impulse decisions. Often times impulsive action takes place in the face of danger or following intense negative emotion. Research agrees that during times of intense negative emotion people are more likely to make rash impulsive decisions.  A psychology/nuerochemistry review paper I recently read made the argument that the initial binge eating episode that can lead to BN is the result of impulsive action. Often this impulsive action is brought on by negative emotion. The act of binge eating is an immediate relief of this negative emotion.  The writers of this paper also make the argument that the purge episode to follow is brought on by a number of factors including resentment following the impulsive decision. This resentment the writers believe can mostly be attributed to the “expectancy that thinness leads to overgeneralized life improvement.”
Compulsive Behavior
The path from impulsive binge eating and purging to compulsive binge eating and purging begins in the dopaminergic reward centers of the brain. People with BN show a similar reaction in this part of the brain during a binge episode as drug addicts do during drug use. The continued reward in this portion of the brain leads  to a tolerance build up. You see dopamine is the chemical responsible for this reward feeling and in order for dopamine to do its job it has to bind with a dopamine receptor. However if dopamine gets release more often than normal, the brain responds by decreasing the number of dopamine receptors. This means in order to get the same reward feeling, it takes more dopamine than normal. However this reaction from the brain only happens after repeated use. Therefore the initial impulsive decision to binge eat does not exactly cause BN it would be the repeated binge eating and purging episodes that lead to BN.