Eating disorders are complex, multifaceted and often fatal. Yet, at least 30 million Americans suffer from an eating disorder and every 62 hours, at least one person dies as a direct consequence of an eating disorder. Is there an impact on the brain reward response on anorexia
Anorexia nervosa, or simply anorexia, is an eating disorder distinguished by uncharacteristically low body weight, a dedicated and purposeful starvation, a phobia-like fear of gaining weight and a distorted body image. This becomes particularly problematic in today’s obesogenic culture which is rich with food and food cues, where social interactions and family activities revolve primarily around eating.
Hence, individuals battling anorexia develop high levels of anxiety and resort to extreme measures, such as compulsive exercise and starvation, to avoid gaining any weight. Around 0.9 percent of American women are affected by anorexia, with a mortality ratio of 5.86 percent. Almost half of the anorexia patients also suffer from a comorbid psychological disorder. One in five anorexia deaths in by suicide.
It’s important to understand that anorexia isn’t about food: it is a destructive and unhealthy coping mechanism to deal with emotional instability. Clinicians have often thought patients were almost wired to reinforce pursuit of thinness somewhere in the brain. This may be closer to reality than originally thought. Thinness, in this situation, is most likely a pursuit that itself is reinforcing, equated with self-worth and achievement. Just like other disorder, anorexia can take over the patient’s life, enveloping work, relationships, and mental health.
Brain reward response on anorexia
As research continues to explore this disorder in greater depths, one recent study uncovered a significant relationship between the brain’s response to taste stimuli and high levels of anxiety. Researchers at the University of Colorado Anschutz Medical Campus found that the brain’s response to taste stimuli could potentially play a fundamental role in driving anorexia as it was associated with high levels of anxiety and an intense impulse for thinness.
Lead researcher, Dr. Guido Frank, MD, associate professor of psychiatry and neuroscience at the University of Colorado School of Medicine, alongside his team, monitored a large group of patients with anorexia nervosa as they tasted sugar during brain imaging.
A greater brain response was observed in the patient in comparison to the control group, which may represent a biological marker for the illness.
Restricting diet was discovered to activate a brain reward circuitry as if the person had taken a drug of abuse or fulfilled a survival behavior, linked with the neurotransmitter dopamine.
Dopamine, as shown in the 80s, is the reinforcing chemical for these sensations. Yet, in this case, it was also noticed to trigger anxiety. This further worsened the tendencies of food avoidance and extended the often-deadly disease.
“When you lose weight your brain reward response goes up,” explained Dr. Frank. “But instead of driving eating, we believe it elevates anxiety in anorexia nervosa, which makes them want to restrict more. This becomes then a vicious cycle.”
The study examined and assessed 56 females battling anorexia nervosa, aged between 11 and 21, and 52 healthy control participants of the same age. Monitoring the participants’ brain scans, the researchers examined their mental responses to sugar.
All the participants learned to relate colored shapes to either receiving or not receiving a sugary solution. In some instances, when they expected sugar, they received nothing, and in other scenarios, they received sugar when they didn’t expect to.
Patients with the eating disorder had stronger responses to the unexpected getting or not getting of sugar water, most likely due to the release of dopamine. In fact, a higher brain response was found indicative of a higher tendency of harm avoidance in participants with anorexia.
Harm avoidance is understood to be a measure of anxiety depicting excessive worrying and fearfulness. This, in turn, further exacerbated body dissatisfaction and the desire for thinness.
The higher the brain response, the lower the weight gain during treatment.
This brain reward response influences the hypothalamus, the region of the forebrain that controls appetite. The researchers hypothesized that such a heightened response elicited by the dopamine reward system could be understood to be a biological adaptation to starvation.
Hence, for individuals that are particularly vulnerable to the development of anorexia nervosa, such as those in mid-adolescence and fighting emotional struggles, sensitivity to food restriction and modified response mechanisms may be considerably enhanced.
According to Dr. Frank, anorexia nervosa behavioral tendencies could modify the brain circuits and influence its taste-reward processing mechanisms. Those already worried or sensitive about their body shape and weight become even more agitated and reactive.
Consequently, a strong response relaying the urgency of being fed might be overwhelming for such patients and trigger greater food restriction instead of eating.
Even though, as the study noted, most people liked and enjoyed sweet tasting things, those with eating disorders related the taste with weight gain and made more significant efforts to avoid it. It was also discovered that the brain activation among the anorexia group was inversely associated with any pleasant experience of eating sugar.
“Our data raises the possibility that adolescents with anorexia nervosa in this study were negatively conditioned to sweet taste and may have developed an inverse association with dopamine release across the larger (brain) reward circuitry,” the study said.
Dr. Frank believes these insights could potentially pave the way for new and more effective treatments for eating disorders. He stated that such finding could be utilized to operate existing biomarkers in such a way so as to design more suitable treatment for this often-fatal illness.
It is important to keep in mind that eating disorders are essentially multifactorial involving a range of biological and psychosocial facets with a strong genetic influence as well. This data offers novel insights and hope. Yet, it is unlikely to explain all cases.
It is vital to have a model of structural and functional brain modifications to assess any potential predispositions that could contribute to the development of anorexia or other eating disorders. Even though it is difficult to accurately determine the origins of any alterations in the brain structure and/or function, it is essential to realize the role of genetics and environmental factors specifically during childhood and adolescence.
About the Author:
Mark S. Gold, M.D. served as Professor, the Donald Dizney Eminent Scholar, Distinguished Professor and Chair of Psychiatry from 1990-2014. Dr Gold was the first Faculty from the College of Medicine to be selected as a University-wide Distinguished Alumni Professor and served as the 17th University of Florida’s Distinguished Alumni Professor.
Learn more about Mark S. Gold, MD
About the Transcript Editor:
Sana Ahmed is a journalist and social media savvy content writer with extensive research, print, and on-air interview skills. She has previously worked as staff writer for a renowned rehabilitation institute, a content writer for a marketing agency, an editor for a business magazine and been an on-air news broadcaster.
Sana graduated with a Bachelors in Economics and Management from London School of Economics and began a career of research and writing right after. Her recent work has largely been focused upon mental health and addiction recovery.
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 a discussion of various issues by different concerned individuals.
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Published on September 12, 2018.
Reviewed & Approved on September 12, 2018, by Jacquelyn Ekern MS, LPC
Published on EatingDisorderHope.com