Reward Circuitry in the Anorexic and Bulimic Brain

Researcher Walter Kaye and his team at the UC San Diego Eating Disorder Center believe that brain imaging may play a key role in shaping the way we understand disordered eating behaviors. The team identified specific reward mechanisms within the brain that may be altered in those struggling with eating disorders and that may contribute to the maintenance of the eating pathology. These findings could lead to the development of new and modern therapies, reverse stigmas associated with eating disorders and usher us into a new era of understanding and sensitivity.

Kaye and his team first aimed to understand how brain structures/responses in those struggling with bulimia and anorexia physically differed from those of their peers.  “The brains of individuals with anorexia nervosa and bulimia nervosa process reward, food and hunger/satiety differently than healthy peers. Women recovered from anorexia nervosa tend to show decreased brain response to both food and money in brain reward regions, whereas women recovered from bulimia nervosa tend to show increased brain reward response.”

How would this function serve to maintain either disorder? For those struggling with AN, the reward response region was more inactive in response to both money and food explaining why women with anorexia are not motivated to eat and maintain the ability to starve themselves. Simply put, the brain associates less reward with the experience of eating and like anything/anyone else that is driven by reward, if the reward is not satisfying, one would not be compelled to engage in that target behavior.

The opposite experience was observed to be true for those with bulimia nervosa. In BN the amplified brain reward response will not diminish once the individual becomes “full.” Imaging suggests that the brain does not appear to have the ability to devalue food after enough has been consumed to sustain the individual, contributing to the propensity to binge eat.

Where do we go from here? While there is a general understanding of the various environmental, social and genetic factors that contribute to the heritability and development of an eating disorder, very little work has been done that helps definitely prove a brain basis to eating disorders. An article from UCSD explains “The history of medicine is that a better understanding of the causes of an illness often leads to more effective treatment. We really know very little about the causes and factors that maintain eating disorders, which has hampered our ability to effectively treat these disorders.”  It is one hope of researchers that with a greater understanding of the biological basis for eating disorders, stigmas (e.g. that it is a disease for the vain, manipulative, willful) will be reduced and individuals will receive better quality treatment within the community.

How may this enhance existing therapies? With a greater understanding of neuro-imaging, clinicians in the field can incorporate biological psychoeducation into the treatment plan in an attempt to improve patients’ understanding of the disorder and validate their experiences. Further, if our clients can have a better understanding of the factors driving their struggles, they will be better able to cope with or manage them effectively.