What diagnostic criterion must be present for anorexia nervosa?

The diagnostic criterion for anorexia nervosa includes the absence of at least three consecutive menstrual cycles, known as amenorrhea. This symptom is indicative of the physiological effects of severe caloric restriction and significant weight loss on the body. In females, this loss of menstruation occurs due to hormonal imbalances that result from the body's inability to maintain normal functioning when it is in a state of starvation or extreme undernutrition.

While the absence of at least one menstrual cycle might suggest a problem with menstrual regularity, the specific stipulation of three consecutive cycles reflects a more severe physiological deterioration related to the malnutrition found in anorexia nervosa. This makes it a clearer diagnostic marker within the criteria of the disorder, helping clinicians to assess the severity of the condition and the impact it has on the individual's health. Additionally, social withdrawal may occur but is not a defining characteristic necessary for the diagnosis. Similarly, significant recent weight gain contradicts the very essence of anorexia nervosa, which involves the pursuit of weight loss and an intense fear of gaining weight.