The pressure to be thin in modern society\u2014especially for women\u2014is pervasive and undeniable. Anorexia nervosa is an eating disorder that causes people to develop an unhealthy obsession with losing weight and being thin, often to the point of becoming dangerously underweight. However, our modern understanding of eating disorders shows us that anorexia is not a social phenomenon resulting from peer and societal pressure to look a certain way. Furthermore, this difficult disease is really about much more than the desire to be thin. Experts like Craig Johnson, Ph.D., director of the eating Disorders Program at the Tulsa, Okla., Laureate Psychiatric Clinic and Hospital, note that the rates of anorexia and bulimia would be much higher if societal pressure was solely or even largely responsible. A huge percentage of women and men will diet, exercise or take other measure at some point in their lives in the pursuit of thinness, but only around 4 percent will develop anorexia or bulimia. Clearly, other forces are at work to help make these routine behaviors so dangerous for a relatively small number of people. Co-morbidity and Underlying Causes For many sufferers of anorexia, serious emotional and psychological distress is at the root of their disordered eating and preoccupation with weight. Mood disorders, such as depression and anxiety, are often co-morbid (co-occurring) with eating disorders, and present when eating disorders begin to develop. Personality disorders and obsessive-compulsive disorders are also fairly common among people living with eating disorders. Strictly limiting diet and losing weight are ways for some people who feel out control to take control over an aspect of their lives, and for people with low self-esteem to increase their sense of self-worth. In addition to these psychological disorders, research has identified five personality traits common among people with eating disorders. These people tend to be (1) obsessive, (2) perfectionist, (3) anxious, (4) novelty-seeking and (5) impulsive. The ways in which some of these traits manifest with eating disorders are not fully understood. Some researchers speculate that obsessive or obsessive-compulsive tendencies, for example, may help people stick to an extreme diet or exercise plan even when they are very hungry, or that perfectionists may be less likely to be satisfied with moderate weight loss and keep pushing themselves toward greater results. Role of Genetics in Eating Disorders Understanding the role of anxiety, control and self-worth is important when it comes to fully understanding eating disorders, but current research suggests that the true \u201csource\u201d of eating disorders goes even deeper than this. There is now significant evidence that genetics play a major role in determining who develops an eating disorder. Of course, connections between psychiatric disorders and genetics are not new ideas. Research has convincingly demonstrated that a wide range of illnesses\u2014including depression, schizophrenia, bipolar disorder and addiction\u2014have strong genetic links. Experts now believe that eating disorders are yet another category of illness that run in families and can be passed from generation to generation. However, the genetic nature of eating disorders is almost certainly complicated. Researchers do not expect to find that a single gene mutation is responsible for anorexia, like the gene linked to Huntington\u2019s disease. Instead, the genetic nature of eating disorders is likely a combination of inherited traits that create a predisposition toward anorexia or another of these illnesses. This is where cultural ideas of beauty and societal pressures come back into play. These factors can interact with a genetic predisposition and bring a latent tendency toward eating disorders to life. Not all of the people with a predisposition to eating disorders will develop one, but when these at-risk people are exposed to certain influences, the potential can become a reality. This means that the unrealistic size and weight expectations that dominate the media are not entirely off the hook. Experts do feel that the rise in eating disorders over the last decade is at least in part due to narrow cultural standards of beauty. But they now believe that these standards play more of an indirect role, and influence the development of eating disorders where a genetic predisposition is already in place.