Neurobiology of Eating Disorders: Clinical Implications
April 29, 2016
Volume:
33
Issue:
4
Figure 1. Neurocircuitry implicated in reward, inhibition, and salience [19-21] Note: Regions in red comprise reward-related neurocircuitry, including the ventral striatum (VS), rostral anterior cingulate cortex (rACC), and ventromedial prefrontal cortex (vmPFC). Regions in blue constitute the cognitive control pathway and include the dorsal caudate (dCaud), dorsal anterior cingulate cortex (dACC), ventrolateral and dorsolateral prefrontal cortex (vl and dlPFC), insula, and parietal lobe. The anterior insula (ant Insula) and anterior cingulate cortex (ACC), in green, make up the salience network.
Figure 2. Activity within the dorsolateral cognitive circuitry associated with decision-making and inhibitory control. Woman recovered from anorexia do not engage reward circuits in the brain in response to money (A), in contrast to healthy women without a history of an eating disorder, who show an increase in brain response in reward circuitry when hungry compared with when satiated. This decreased sensitivity to reward may explain why individuals with anorexia are able to ignore hunger-related urges and starve themselves. Women recovered from anorexia also show increased activation of cognitive “self-control” circuits in the brain (B), perhaps making them more effective in controlling the urge to eat.[1] CW, healthy comparison women; RAN, women recovered from anorexia nervosa. *P < .05; **P < .01; error bars represent the standard error for each group.
Significance for the Practicing Psychiatrist
Eating disorder behaviors can range from dangerous caloric restriction to eating that feels out of control—often combined with unhealthy weight control behaviors, such as self-induced vomiting or laxative abuse. Anorexia nervosa, bulimia nervosa, and binge eating disorder are the most prevalent eating disorders. Diagnostically, anorexia nervosa requires low body weight, intense fear of or behavior that interferes with weight gain, and disturbance in the perception of one’s weight or shape.
Criteria for bulimia nervosa include recurrent binge eating (eating a large amount of food in a discrete period of time accompanied by a sense of loss of control) and actions meant to counteract weight gain (eg, self-induced vomiting), as well as overvaluation of body weight or shape. Binge eating disorder involves recurrent binge eating without inappropriate compensatory behavior. Individuals with eating disorders frequently report extreme body dissatisfaction, anhedonia, anxiety, and difficulty tolerating negative emotions, although these are not required for diagnosis.
The cause of eating disorders remains unknown. Given that eating disorders reflect a discrepancy between the physiological need to eat and the drive to eat, it has been hypothesized that these individuals have a fundamental disturbance of appetite regulation. In recent years, advances in brain imaging have provided new insights into neural pathways that play a role in emotions, reward, salience, and inhibition of eating.Eating Disorders
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