The Neurobiology of Eating Disorders can be traced partly to the gut and hypothalamic mechanisms contribute to the regulation of energy metabolism and eating behaviors and higher order, corticolimbic systems may play a role in the pathophysiology of eating disorders and may override homeostatic pathways .
There are numerous neural-networks which play a part in eating disorder activation or stimulus. The first of these is the insula and anterior cingulate. The insula processes basic sensory information about food.
The second pathway, including the nucleus accumbens, putamen, caudate, orbitofrontal cortex and amygdala which are responsible for rewarding and monitoring the value of eating and contribute to the approach or avoidance of food .
The third network, the dorsal caudate and dorsal anterior cingulate, prefrontal cortex, and parietal cortex are responsible for control consumption and consideration of both short and long term outcomes of food consumption. This system weighs the reward value of food and the consequences of consuming it to maintain homeostasis .
Connection Between Neurobiology and Eating Disorders
Individuals that struggle with eating disorders, the processing and approach to food varies, neurobiologically. Those with binge eating (Bulimia Nervosa or Binge Eating Disorder), show reduced responses when anticipating food reward, but increased responses to the receipt of food.
Those with Binge Eating Disorder or Bulimia nervosa show regions of brain that respond which is the insula and ventral striatum. Those with Anorexia nervosa show increased and anxious sweet-taste anticipation and reduced responses to the taste itself. The areas of the brain that are activated for those with Anorexia nervosa is the insula, striatum, and prefrontal cortex .
These differences in the way brains anticipate and process food rewards correlates to the way individuals with eating disorders approach food. Besides in response to food, other environmental stimuli are activated, which could indicate a generalized deficit in neural pathways.
Imaging research in eating disorders shows dysfunction in the neural valuation of reward and punishment, meaning that when making choices about financial decisions, those with past or current eating disorders, are unable to differentiate between wins and losses. This research could suggest that individuals with eating disorders may have difficulty evaluating rewards within their environment.
Eating Disorder Symptoms Connected to Neurobiology
Research has shown that dysregulation of these reward and inhibitions systems may contribute to disordered eating. When looking at Anorexia Nervosa (AN), when severe food intake occurs, it over activates the inhibition control networks and under activates the reward networks.
When looking at Bulimia Nervosa (BN), there seems to support for the dysregulation of both inhibition and reward pathways due to the characteristics of bulimia symptoms. In Binge Eating Disorder (BED), with overeating, there seems to be altered sensitivity of the ventral reward pathways .
In addition to food processing deficits, individuals with eating disorders also show difficulty with inhibition control. Typically those with BN or BED show inhibition with substance abuse, shoplifting and self injury. Neuroimaging studies have suggested this may relate to failure in the frontostriatal circuits that regulate behaviors .
Various imaging studies have also shown ineffective or insufficient in activation of the control related regions and may relate to difficulty in stopping eating during binge episodes, as well as resisting urges to purge . Those with AN, show an enhancement of cognitive control and may relate to their ability to restrict intake even when starved.
MRI studies have shown that those with AN have increased activity within the dorsolateral cognitive circuitry which is responsible for decision making and inhibition [1, 2].
Eating disorders and their subcategories have distinct features and symptomatology, but seem to share biological underpinnings. Eating disorders are hereditary and individuals seem to have similar temperaments. Those with eating disorders, as children, prior to eating disorder symptomatology, show anxiety, obsessiveness, perfectionism, and achievement oriented behaviors .
Also important to note is a faulty reward processing system, which is similar across all subtypes of eating disorders. Dopamine, a neurotransmitter that motivates and relaxes, is altered in those with both AN and BN disorders. In those with BN, the brain has a weaker response of dopamine in the reward regions and those with AN are overly sensitive to dopamine responses . In those with AN, the orbitofrontal cortex, signals to the body to stop eating.
Those with AN seem to have a higher rate of activity in this region, the dorsal striatum, which is linked to habitual behavior. Previously, those with AN were stereotyped as having significant willpower to avoid food even when starving.
The right insula is also affected with those with AN. This part of the brain is responsible for taste sensations, and introception to be able to sense one’s own bodily signals. Those with AN, will ignore or numb out the signal of hunger and show hypersensitivity to body sensations [1,2].
Countering support for neurobiology of eating disorders, is that in AN, brain and bodies are severely malnourished which can also cause changes in brain activity and may return to normal after the refeeding process. There are various pre existing features of the brain that put individuals at risk for eating disorders, but other changes are in response to one’s habits.
Impact of Understanding Neurobiology Connection
The Neurobiology of Eating Disorders and its understanding, can help in treatment and understanding of the etiology of the disorder. Helping a patient understand that it is not just behavioral, that there are brain networks and regions that are not functioning properly can help caregivers and individuals further understanding of the illness .
Eating disorders affect 10-24 million people.
Many individuals seek treatment and have seasons of relapse and often times repeating treatment again and again. According to Dr Kaye, Professor of Psychiatry and Director of the Eating Disorder Treatment and Research Program and the University of California, San Diego School of Medicine, states that one reason for difficulty in developing new programs is the fields limited understanding of the the brain contributes to the disorders symptoms .
Kale and his colleagues are working to develop imaging based treatment that specifically addresses the neurobiology of AN. Kale reports that the target of eating disorders is anxiety, and understanding why those with AN feel extreme anxiety with or in anticipation of food. Recent research by this team has show specific alterations in the brain associated with food and anxiety in AN individual’s [3, 4].
With this discovery, treatment can focus on education and biology related symptoms for families and patients. It allows individuals to understand why their eating disorder is driving them to restrict, or binge, and helps target anxiety around food.
When we eat the brain systems of reward is an active participant when eating. When we anticipate food, it activates the neural systems that create a pleasure and reward response . This helps understand the impact of food rewards on eating behaviors.
Pleasure needs to be motivational or as a want, for a food reward to influence eating behavior. Incentive salience is reward and cues, which helps the brain determine foods motivational value. This suggests that cravings for foods, can be triggered by imagination, smells, sights, and taste of foods.
In conclusion, The Neurobiology of Eating Disorders, is a neurobiology process and symptomatic of dysregulation or overproduction of neural pathways within the brain. This can aid in therapist treatment and education approach to assisting patients. Further training and learning for clinicians and support team members can aid in the recovery processes.
Community Discussion – Share Your Thoughts Here!
What are your thoughts on eating disorders having a biological base? Would your treatment and recovery go differently if you had further education on the neurobiology of eating disorders?
About the Author: Libby Lyons, MSW, LCSW, CEDS is a specialist in the eating disorder field. Libby has been treating eating disorders for 10 years within the St. Louis area, and enjoys working with individuals of all ages.
The opinions and views of our guest contributors are shared to provide a broad perspective of eating disorders. These are not necessarily the views of Eating Disorder Hope, but an effort to offer discussion of various issues by different concerned individuals.
We at Eating Disorder Hope understand that eating disorders result from a combination of environmental and genetic factors. If you or a loved one are suffering from an eating disorder, please know that there is hope for you, and seek immediate professional help.
Last Updated & Reviewed By: Jacquelyn Ekern, MS, LPC on January 8, 2017.
Published on EatingDisorderHope.com