The exact cause of anorexia nervosa is not thoroughly understood. Perhaps part of the explanation for its prevalence in economically developed nations may be the messages the media sends regarding ideal beauty and attractiveness. These messages often promote thinness as the female ideal. In order to be thin or slender, some people achieve and maintain a weight that may not always be healthy for their bodies. In some cases, it is possible to be slender and healthy at the same time. However, it becomes a serious health problem when people use detrimental methods (e.g., starvation) to achieve thinness.

Generally, a combination of various factors is believed to contribute to the development of anorexia nervosa. These include:

• Gender. Females are more likely to develop anorexia nervosa than males. However, males may also develop this type of eating disorder. According to the U.S. National Institute of Mental Health (NIMH), about 5 to 15 percent of patients with anorexia nervosa or bulimia nervosa are male.
  
  
• Age. Even though anorexia nervosa may occur at any age, it is more common among teenagers and young adults (people in their 20s and early 30s).
  
  
• Heredity. Anorexia nervosa is more common among people with close family members with the eating disorder. Studies of twins also support this theory. However, it is not clear specifically how genetics plays a role. Researchers believe that genetics may contribute by creating a tendency toward perfectionism, sensitivity and perseverance, all traits associated with anorexia nervosa.
  
  
• Emotional disorders. Often, people with anorexia nervosa have other types of psychological disorders, including depression, anxiety disorders (e.g., obsessive-compulsive disorder) and substance abuse. Generally, the presence of a pre-existing emotional disorder often reinforces the eating disorder and vice versa.
  
  
• Certain personality traits. Individuals with anorexia nervosa often exhibit the following personality traits:
  
  
• • Low self-esteem and feelings of inadequacy or lack of control in life.
    
    
  • Perfectionism. Wanting to look and be perfect is often equated with thinness.
    
    
  • Lack of communication skills. Patients with anorexia nervosa often have difficulty communicating negative emotions and/or resolving conflict.
    
    
• Stress. Sometimes, anorexia nervosa may be triggered by stressful situations and/or traumatic events, including a history of abuse (e.g., physical, sexual), dysfunctional family, divorce, death of a family member or friend or starting a new school or job.
  
  
• Family and social influences. Individuals whose parents, siblings or other close family members and friends are overly critical of their weight, appearance and/or eating habits may be at increased risk of engaging in harmful methods of weight control (e.g., starvation, purging), which can put them at risk of developing anorexia nervosa.
  
  
• Competitive sports and performance arts. While competitive sports or artistic activities (e.g., ballet, gymnastics, figure skating, wrestling, acting) do not directly cause anorexia, people, especially females, who participate in these activities may be at increased risk of using harmful methods of weight control (e.g., abusing diet pills) due to the strict weight requirements of certain sports or performance arts. Prolonged use of such methods may put individuals at risk of developing anorexia nervosa.