Anorexia Nervosa

Among feeding and eating disorders, Anorexia Nervosa is the most well-known. Perhaps its fame comes from cinematic portrayals (such as in the film To the Bone), but most of us have some idea—whether accurate or not—of what anorexia is and how dangerous it can be. Here, I’ll try to explain it in my own words.

The term anorexia includes the prefix "a-", which indicates a lack or absence. We’ve encountered similar terms before, such as when discussing schizophrenia and its negative symptoms. For example, "asocial" means a lack of (or significantly reduced) tendency toward social interaction. In anorexia, what’s lacking is appetite. Anorexia, therefore, is a condition that can arise in various situations, such as during illnesses like cancer.

But then, when we associate anorexia with the image of someone who is excessively thin, what are we referring to? This refers to the psychological disorder known as Anorexia Nervosa. According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), Anorexia Nervosa is characterized by:

1. Severely restricted calorie intake, leading to excessively low body weight.
2. An intense fear of gaining weight or engaging in behaviors that prevent weight gain.
3. Distorted body image, where one’s perception of weight or shape interferes with recognizing the seriousness of being underweight.

To determine whether someone’s weight is low relative to their characteristics, the World Health Organization (WHO) uses the Body Mass Index (BMI). The formula for BMI is body weight (in kilograms) divided by height (in meters) squared. If this index is greater than 18.5 kg/m², the person is not considered underweight. For values below this threshold, four levels of severity are defined: mild, moderate, severe, and extreme.

Anorexia Nervosa may also present with various physical symptoms (diagnostic markers), such as:

• Leukopenia: Low white blood cell count.
• Sinus bradycardia: A resting heart rate below 60 beats per minute.
• Low bone mineral density: Fragile bones.
• Amenorrhea: The cessation of menstrual periods.

The psychological component of the disorder lies in the perception of one’s weight as excessive, paired with an intense fear of becoming fat. It’s possible for individuals to admit that they are thin but still perceive certain body parts (typically the abdomen, buttocks, or thighs) as "fat." People with Anorexia Nervosa may use strategies to maintain low body weight, such as excessive physical activity and/or inappropriate purging behaviors like self-induced vomiting or laxative use.

Anorexia Nervosa is often accompanied by: a fear of eating in public, feelings of depression and inadequacy, rigid thinking, a desire to control one’s environment, reduced social interaction.
This disorder is more common among young women, with less known about its prevalence in men. Estimates suggest a female-to-male ratio of 10:1.

Sources:

• American Psychiatric Association (2013) - Diagnostic and Statistical Manual of Mental Disorders (5th ed.).
• Bernhill, J. W. (2014) - DSM-5 Clinical Cases.

I also recommend watching this video.

If you’d like me to describe another psychology topic in my own words, feel free to ask in the comments!