eating disorders - Medical Dictionary

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eating disorders		A group of disorders characterized by physiological and psychological disturbances in appetite or food intake. [ Articles \| Books \| Images \| Discussion groups ]

Additional comments : (Appetite Disorders) First Familial Study Of Anorexia Nervosa In Men Shows Nine-Fold Increase Of Risk Among Women In Immediate Family Women contract full or partial anorexia nervosa more than nine times more frequently when a man in the family has the eating disorder, UCLA study shows. Victims of anorexia nervosa suffer severe malnutrition because they refuse to eat enough to maintain a normal body weight. They often exercise excessively and sometimes use laxatives or induce vomiting in their efforts to lose weight. As the bodies of victims struggle to conserve resources, menstrual periods stop and the body starts to lose calcium from the bones. Severe cases can lead to an irregular heartbeat or heart failure as breathing and blood pressure rates decline. Source: University Of California, Los Angeles Specific Regions Of Brain Implicated In Anorexia Nervosa Just why those with anorexia nervosa are driven to be excessively thin and seem unaware of the seriousness of their condition could be due to over-activity of a chemical system found in a region deep inside the brain, a University of Pittsburgh study suggests. The disorder affects about 1 percent of American women, some of whom die from complications of the disease. The research may point to a molecular target for development of more effective treatments than those currently available. The study is the first to use positron emission tomography (PET) imaging to assess the activity of brain dopamine receptors, a neurotransmitter system that is best known for its role in controlling movement. These receptors also are associated with weight and feeding behaviors and responses to reinforcement and reward. Researchers used a harmless molecule designed to bind to the dopamine D2 and D3 receptors that lie on the membrane surface of neurons. Ten women who had recovered from anorexia nervosa for more than a year were studied, as were 12 normal female subjects. Because malnourishment affects brain chemistry, the researchers did not include acutely ill women in their study. Since other studies have found reduced binding of these dopamine receptors in both people who are obese and those who have substance use problems, researchers hypothesized that they would find just the opposite in women with anorexia. Indeed, there was increased receptor binding in the basal ganglia's antero-ventral striatum in the women with a history of anorexia nervosa irrespective of their age, body mass index or time since recovery, but not in any of the healthy women. The antero-ventral striatum is an area known to modulate reward and reinforcement and is therefore important in learning from experience. Alteration in dopamine function may affect the value of perceived rewards, or perhaps make it difficult to associate good feelings with things most people find rewarding. Consequently, people with anorexia nervosa may appear to be obsessive about certain stimuli that may be uniquely rewarding to them, but may not be able to respond well to stimuli related to food or pleasure. Source: University Of California, Los Angeles Altered Brain Chemistry In Bulimia Nervosa Patients Persists After Recovery Researchers at the University of Pittsburgh Medical Center's (UPMC) Western Psychiatric Institute and Clinic have found evidence supporting the possibility that an alteration of brain chemistry contributes to the development of bulimia nervosa and persists even after recovery from the disorder. Women with bulimia nervosa, when bingeing and purging, are known to have alterations of brain serotonin activity and mood as well as obsessions with perfectionism. Serotonin is a neurotransmitter that helps regulate mood. This study found that these alterations and symptoms persisted after recovery from bulimia nervosa, suggesting that they are not merely a consequence of abnormal eating behaviors. Theoretically, altered serotonin activity could cause anxious and obsessive behaviors and affect the control of appetite and thus contribute to a vulnerability to develop bulimia nervosa. Bulimia nervosa affects about 1 to 3 percent of women and most commonly occurs in women who are of normal body weight. Onset is usually during adolescence and is characterized by bingeing and purging, either by vomiting or using laxatives. Women with the disease often have a distorted image of their bodies, changes in brain chemistry and psychiatric symptoms such as depression, anxiety, obsessive-compulsive disorder and alcohol or other substance abuse. Though researchers know the symptoms and effects of bulimia, the exact causes of the disorder have yet to be uncovered. Worsening Bulimia May Deplete Hormone That Regulates Appetite Previous studies have noted that some bulimia nervosa patients have low levels of a hormone called leptin in their blood, while others have normal levels. Researchers from Italy suspect this hormone disparity may relate to the severity of the disease. Leptin is thought to influence body weight through its action on the hypothalamus, the brain portion that helps regulate appetite and satiety. It is known that when body fat and weight drop past a certain point, leptin blood levels drop, stimulating appetite. But these study findings suggest that factors other than body weight changes -- such as the chronic malnutrition and bingeing behavior -- may also impair leptin secretion. The bulimics in the low-leptin group had similar body weight to the normal-leptin bulimics. Bulimia patients generally exhibit normal body weight but their eating habits are far from normal. They take in large amounts of calories during binges but regurgitate most of them by vomiting. They also often choose unhealthy foods during binges and may suffer from chronic nutrient deficiencies, according to the study. Also, a previous study found that binge eating in healthy individuals affected the normal production cycle of leptin. Source: Center For The Advancement Of Health Brain's Opioid Receptors -- or Endorphin System -- May Hold Key to Treatment Possibilities for Bulimia Patients The role of the brain's opioid receptor system or endorphin system may hold the key to understanding and treating bulimia nervosa, according to researchers. Bulimia nervosa,which is 10 times more common in females than in males, affects 12 percent of adolescent girls and young women in the United States. Bulimia may become chronic and lead to serious health problems,including seizures, irregular heartbeat, dental erosion, swollen salivary glands, gastrointestinal irritation and electrolyte imbalances. In rare cases, it may be fatal. While the cause of bulimia nervosa is still unknown, research shows that certain brain chemicals may function abnormally in bulimia patients.This research may point toa molecular target for development of more effective treatments than those currently available. Researchers indicate that medications that affect the brain's opioid receptor system and approaches to treatment for substance abuse disorders may be helpful in treating bulimia. Source: Society of Nuclear Medicine

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