CW: This post will discuss anorexia and current research that reviews its relation to the brain.
Please read with caution.
Eating disorders are a class of complex and life-threatening mental illnesses characterized by disturbances in thoughts and behaviors relating to food, eating, body weight, and shape. Two of the most common eating disorders are bulimia nervosa and anorexia nervosa. Anorexia nervosa has one of the highest mortality rates amongst eating disorders. Developing an understanding of anorexia nervosa at the psychological, neurological, and medical levels is imperative for the development of treatment and prevention.
Recent research has found that brain connectivity and activity are abnormal in individuals that engage in anorexic behaviors and cognitions. Utilizing fMRI data, researchers observed hyperconnectivity in the dorsal visual network for anorexia nervosa and body dysmorphic disorder, this region associated with visual perception of one’s body (Moody et al., 2021). Specifically for anorexia nervosa, researchers noted that there were no differences of connectivity in the parietal lobe when compared to healthy controls (Moody et al., 2021). These results implicate distinctions between anorexia nervosa and body dysmorphic disorder as well as information for novel treatment methods. Is it possible that brain stimulation of an individual with anorexia nervosa may lead to better outcomes?
The answer to that question is leaning towards yes. A longitudinal study in Canada, observed 16 patients with treatment resistant anorexia nervosa undergo deep-brain stimulation and open-label continuous stimulation for a year, they then recorded body mass index, mood, anxiety, mood regulation, and neural circuitry at the 6- and 12-month marks. The study found that after stimulation patients had increased BMI, decreased negative mood, and greater mood regulation suggesting that deep brain stimulation is effective for the treatment of anorexia nervosa (Lipsman et al., 2017).
While the answer may be yes or yes-leaning, this treatment modality is not widely accessible and is quite costly. What are other researchers learning about anorexic brains that can inform more accessible treatment options for individuals?
How about a medicinal treatment for anorexia nervosa?
A recent animal study, has observed shifts in anorexic behaviors thorough the stimulation of a dopamine-serotonin brain circuit and administration of a dopamine receptor antagonist (Cai et al., 2022). More explicitly, this multi-step experiment first found dopamine and serotonin neurons communicate with each other to regulate feeding, overeating occurred when dopamine had lower-frequency firing, thus when dopamine has greater frequency firing there’s a lack of appetite and excessive exercising. The researches then found that this relationship is mediated by a dopamine receptor DRD1. By inhibiting this receptor with an antagonist, normal eating and exercise behavior were restored to a certain degree which may implicate DRD1 antagonist as a pharmacological treatment to anorexia nervosa, following extensive supportive research (Cai et al., 2022).
There is much more to be understood about anorexia nervosa and current research is looking to the brain to inform society as to what is happening when an individual is faced with such a serious mental-illness and considering developing different clinical means of addressing the issue.
Cai, X., Liu, H., Feng, B. et al. A D2 to D1 shift in dopaminergic inputs to midbrain 5-HT neurons causes anorexia in mice. Nat Neurosci 25, 646–658 (2022). https://doi.org/10.1038/s41593-022-01062-0
Lipsman, N., Lam, E., Volpini, M., Sutandar, K., Twose, R., Giacobbe, P., … & Lozano, A. M. (2017). Deep brain stimulation of the subcallosal cingulate for treatment-refractory anorexia nervosa: 1 year follow-up of an open-label trial. The Lancet Psychiatry, 4(4), 285-294. https://doi.org/10.1016/S2215-0366(17)30076-7
Moody, T.D., Morfini, F., Cheng, G. et al. Brain activation and connectivity in anorexia nervosa and body dysmorphic disorder when viewing bodies: relationships to clinical symptoms and perception of appearance. Brain Imaging and Behavior 15, 1235–1252 (2021). https://doi.org/10.1007/s11682-020-00323-5