... characteristics are as follows: * Periods of compulsive bingeing followed by forced vomiting or the use of laxatives or other means. * Binge-eating is reasonably common among dieters. When it occurs more than 2 times a week and for over 3 months, it is considered abnormal. * Bulimics are obsessive about their weight, though it is usually nearer normal than anorexics. Most of them are within 10% of correct body weight. Explanations of Anorexia nervosa: The biological (medical) explanations Genetic Transmission: Twin studies illustrate this. Holland et al found a 55% concordance rate for identical (MZ) twins. (Monozygotic). Compare with only 7% for non-identical (DZ). Evaluation: The fact that not all MZ twins develop the disorder means that genetic transmission cannot be the sole explanation. Biochemical abnormalities: Disordered hormones may be a cause. Amenorrhoea may occur before weight loss, which suggests a disorder of the endocrine system. Fava et al found changes in the levels of serotonin and ...

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