New Insights into Anorexia Discovered
Science Daily reports that new technology provides insights into brain abnormalities in patients with anorexia nervosa that may contribute to the symptoms found in people with the disorder.
Walter Kaye, MD, professor of psychiatry and director of the Eating Disorders Program at the University of California, San Diego, and colleagues describe dysfunction in certain neural circuits of the brain that may help explain why people develop anorexia.
“Currently, we don’t have very effective means of treating people with anorexia,” said Kaye. “Consequently, many patients with the disorder remain ill for years or eventually die from the disease, which has the highest death rate of any psychiatric disorder.”
Childhood personality and temperament may increase a person’s vulnerability to developing anorexia, according to Kaye. Some predisposing factors, including some that may be inherited, such as perfectionism, anxiety, or obsessive-compulsive tendencies may precede the onset of an eating disorder. These traits become intensified during adolescence as a result of many factors such as hormonal changes, stress, and culture.
“Adolescence is a time of transition, when individuals must learn to balance immediate and long-term needs and goals in order to achieve independence,” said Kaye. “For such individuals, learning to cope with mixed societal messages and pressures may be overwhelming, exacerbating underlying traits of anxiety and a desire to perfectly achieve.”
Once a person develops anorexia, starvation and malnutrition cause profound effects on the brain and other organs, including neurochemical imbalances which may exaggerate the preexisting traits and accelerate the progress of the disease.
“Individuals with anorexia tend to report that dieting reduces anxiety, while eating increases it,” said Kaye. “This is very different from most individuals, who experience hunger as unpleasant.” The need to avoid being anxious actually drives weight loss in anorexia nervosa, resulting in severe emaciation and malnutrition.
People with anorexia also tend to not experience pleasure or “live in the moment.” They often worry obsessively about the consequences of their behaviors and are overly concerned about making mistakes. Imaging studies suggest that people with anorexia have an imbalance between circuits in the brain that regulate reward and emotion (the ventral or limbic circuit) and circuits that are associated with consequences and planning ahead (the dorsal or cognitive circuit), according to co-author Julie L. Fudge of the Department of Psychiatry & Neurobiology at the University of Rochester Medical Center.
Brain imaging studies also show that individuals with anorexia have alterations in parts of the brain that are involved with bodily sensations, such as sensing the rewarding aspects of pleasurable foods, according to co-author Martin Paulus, UC San Diego professor of psychiatry, who heads UC San Diego’s Laboratory of Biological Dynamics and Theoretical Medicine. “Anorexics may literally not recognize when they are hungry,” he said.
One such brain region is the anterior insula, which is very important for self-awareness of internal body signals (interoception). Symptoms of anorexia such as distorted body image and diminished motivation to change could also be related to disturbed interoceptive awareness.
“Anorexia is very complicated, and there needs to be a paradigm shift in understanding its underlying cause,” said Kaye. “We’re just beginning to understand how the brain is working in people with this disorder.”
Kaye noted that the temperament and personality traits that may create a vulnerability to develop anorexia may also have a positive aspect. These traits include attention to detail, concern about consequences, and a drive to accomplish and succeed.
“It’s my clinical experience that many individuals who recover from anorexia do well in life,” he said.