Anorexia Nervosa: Types, Causes, Symptoms, Diagnosis, and Treatment

Anorexia nervosa is a complex eating disorder characterized by the obsessive pursuit of having a thin figure through dieting, extreme weight loss, and disturbance of body image. It is characterized by voluntary restriction of food intake, distorted body image, and fear of gaining weight.

It is an eating disorder usually observed in adolescents. Concerns about body image and dieting are very common in modern society females. It is associated with low self-esteem and perfectionists with obsessive-compulsive traits. Genetic vulnerability, temperament, and psychological and environmental factors also mediate the illness.

Epidemiology – Among women, lifetime prevalence is approximately 1%. Less common in males (1:10). Incidence is increasing.

Anorexia Nervosa: Types

There are two subtypes of Anorexia nervosa −

  • Binge-eating / purging type − Patients with anorexia could show binge eating and purging behavior. They are significantly underweight.

  • Restricting type − The individual uses restricting food intake, fasting, diet pills, or exercise as a means for losing weight. There are no recurrent episodes of binge eating or purging present.

Complications – Malnutrition, dehydration, electrolyte imbalances, increased susceptibility to infection, hypoalbuminemia, and life-threatening cardiovascular complication.

Anorexia Nervosa: Causes

No single cause has been identified.  It probably happens as a result of the following factors: a. Biological b. Environmental c. Psychological.

  • There appear to be some genetic components with identical twins more often affected than fraternal twins.

  • Cultural factors also appear to play a role, with social pressure to be thin and attractive.

  • Additionally, it occurs more commonly among those involved in activities that value thinness, such as high-level athletics, modelling, and dancing.

  • Anorexia usually begins following a major life-change or stress-inducing event.

Anorexia Nervosa: Symptoms

Anorexia nervosa is an eating disorder characterized by the tendency to lose weight to the point of starvation. A person with anorexia nervosa may exhibit several signs and symptoms, the type and severity may vary and be present but not readily apparent.

Signs and symptoms may be classified as physical, cognitive, affective, behavioral, and perceptual −

Physical Symptoms

  • A low body mass index for one's age and height

  • Amenorrhea

  • Dry hair and skin, as well as hair thinning

  • Fear of even the slightest weight gain

  • Rapid, continuous weight loss

  • Lanugo − soft, fine hair growing over the face and body

  • Bradycardia or tachycardia

  • Chronic fatigue

  • Orange discoloration of the skin, particularly the feet (Carotenosis)

  • Infertility

  • Halitosis

  • Hypotension or orthostatic hypotension

  • Severe muscle tension, aches, and pains

  • Insomnia

  • Abdominal distension

Cognitive Symptoms

  • An obsession with counting calories and monitoring the fat contents of food

  • Admiration of thinner people

  • Thoughts of being fat or not thin enough

  • An altered mental representation of one's body

  • Impaired theory of mind, exacerbated by lower BMI and depression

  • Difficulty in abstract thinking and problem-solving

  • Rigid and inflexible thinking

  • Poor self-esteem

  • Hypercriticism and perfectionism

Affective Symptoms

  • Depression

  • Ashamed of oneself or one's body

  • Anxiety disorders

  • Rapid mood swings

  • Emotional dysregulation

  • Alexithymia

Behavioral Symptoms

  • Food/energy restrictions

  • Food rituals, such as cutting food into tiny pieces, refusing to eat around others, and hiding or discarding food

  • Purging (only in the anorexia purging subtype) with laxatives, diet pills, ipecac syrup, or diuretics

  • Excessive exercise including micro-exercising

  • Self-harming or self-loathing

  • Solitude

Perceptual Symptoms

  • Perception of self as overweight, in contradiction to an underweight reality (namely " body image disturbance).

  • Intolerance to cold and frequent complaints of being cold.

  • Altered body schema (i.e. an implicit representation of the body evoked by acting)

  • Altered interoception.

Risk Factors

The major risk factors include −

  • Being susceptible to depression and anxiety.

  • Having difficulty handling stress.

  • Being excessively worried, afraid, or doubtful about the future.

  • Holding specific ideas regarding beauty and health, which may be influenced by culture or society.

  • Having a high level of emotional restraint or control over their behavior and expression.

  • Being a perfectionist and overly concerned about rules.

  • Having a negative self-image.

  • Having eating problems during early childhood or infancy.

  • Having had an anxiety disorder during childhood.

  • Hormonal changes that occur during puberty, plus feelings of anxiety, stress, and low self-esteem.

  • The fashion industry and media messages suggesting that being thin is beautiful may have an impact.

  • Physical, sexual, emotional, or another type of abuse.

  • Family or other relationship problems.

  • Being bullied.

  • A fear of exams and pressure to succeed.

  • A stressful life event, such as bereavement or becoming unemployed.

Anorexia Nervosa: Diagnosis

A diagnostic assessment includes the person's current circumstances, biographical history, current symptoms, family history, and mental state examination, focusing on views on weight and patterns of eating.

Diagnostic criteria for anorexia nervosa (DSM 5) (all of which need to be met for diagnosis) are −

  • Restriction of energy intake relative to requirements leading to low body weight. (Criterion A)

  • Intense fear of gaining weight or persistent behaviors that interfere with gaining weight. (Criterion B)

  • Disturbance in the way a person's weight or body shape is experienced or a lack of recognition about the risks of low body weight. (Criterion C)

Anorexia Nervosa: Treatment

Treatment for anorexia nervosa tries to address three main areas −

  • Restoring the person to a healthy weight.

  • Treating the psychological disorders related to the illness.

  • Reducing or eliminating behaviors or thoughts that lead to disordered eating.

Optimal treatment also includes and monitors the behavioral change in the individual as well.

  • Restore weight between ideal and the patient concept of optimal weight.

  • Start calorie intake by approximately 1200-1800 kcal/day and increase intake (3000 kcal/day at least).

  • Ideal weight gain 0.5 – 1 kg/week

  • Micronutrients – Zinc, Calcium(1500 md/day), Vitamin D(400 IU/day), Essential fatty acids, omega-3 fatty acids, docosahexaenoic acid(DHA), eicosapentaenoic acid(EPA).


  • Counselling

  • Cognitive Behavioral Therapy

  • Family therapy is more effective than individual psychotherapy in adolescents


Pharmaceuticals have limited benefits for anorexia itself. However, medicines such as antidepressants and Olanzapine can be prescribed to some patients.

Anorexia Nervosa: Prevention

Anorexia Nervosa can be prevented by the following ways −

  • Use a health promotion approach.

  • Focusing on building self-esteem.

  • Positive body image.

  • A balanced approach to nutrition and physical activity.


Anorexia nervosa / anorexia is an eating disorder characterized by low weight, food restriction, body image disturbance, fear of being overweight, and, an overpowering desire to be thin.

The DSM-5 describes this perceptual symptom as "body image disturbance”. They may weigh themselves frequently, eat small amounts, and only eat certain foods. Some exercise excessively forces themselves to vomit (in the "anorexia purging" subtype) or use laxatives or binge eat. Medical complications may include osteoporosis, infertility, and heart damage, along with the cessation of menstrual periods. The cause of anorexia is currently unknown, probably genetic and environmental factors including social pressure to be thin and attractive. 

Treatment of anorexia involves restoring the patient to a healthy weight, treating their underlying psychological problems, and addressing behaviors that promote the problem. Medications help with associated anxiety or depression. Different therapy methods may be such as cognitive behavioral therapy or may benefit. Sometimes people require admission to a hospital to restore weight. Some people with anorexia will have a single episode and recover while others may have recurring episodes over years. Many complications improve or resolve with the regaining of weight.

Dr. Durgesh Kumar Sinha
Dr. Durgesh Kumar Sinha


Updated on: 16-Feb-2023


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