Key points
- Disordered eating (unstructured meals, grazing) is common, but the eating disorders anorexia nervosa, bulimia nervosa and binge eating disorder are relatively rare. They affect 1–3% of the female population.
- Eating disorders carry serious health risks and often involve secrecy and shame. Specialized treatment resources are scarce. For these reasons, it is often primary care providers who diagnose and treat eating disorders.
- People rarely reveal that they have an eating disorder. Instead, they present with problems such as constipation or mood instability, or seek weight loss advice.
- Eating disorders have the highest mortality rate of any psychiatric illness. About 10% of people with eating disorders die within 10 years of onset.
Symptoms
Anorexia nervosa
- intense fear of gaining weight or becoming fat
- restricted food intake, leading to significantly low body weight for one's age and development
- disturbed perception of one's body and persistent failure to recognize the seriousness of the low body weight
- physical symptoms such as amenorrhea and emaciation.
Bulimia nervosa
- recurrent episodes of binge eating with a sense of lack of control
- recurrent, inappropriate compensatory behaviours to prevent weight gain (e.g., self-induced vomiting, misuse of laxatives or diuretics, fasting or excessive exercise)
- self-evaluation that is unduly influenced by body shape and weight.
Binge eating disorder
- recurrent episodes of binge eating with a sense of lack of control and distress
- no inappropriate compensatory behaviour as in bulimia nervosa.
Prevalence
- Anorexia nervosa is more common in females and tends to begin in adolescence or early adulthood. About 5% of young females have the disorder
- Bulimia nervosa is more common in females and tends to begin in adolescence or early adulthood. About 1–3% of people will be diagnosed with bulimia nervosa in their lifetime.
- Binge eating disorder equally affects males and females. About 1–5% of people have the disorder. It tends to begin at a later age than anorexia nervosa or bulimia nervosa.
- Eating disorders have the highest mortality rate of any psychiatric illness. About 10% of people with eating disorders die within 10 years of onset.
Causes
Genetic and physiological factors
- Many studies show that eating disorders involve genetic factors. Studies suggest an estimated heritability of 58–88% for anorexia nervosa, 28–83% for bulimia nervosa and 57% for binge eating disorder.
- First-degree relatives of people with anorexia nervosa or bulimia nervosa have an increased risk of developing the disorders. They also have an increased risk of bipolar and depressive disorders.
- Childhood obesity increases the risk of developing bulimia nervosa.
- There may be familial transmission of bulimia nervosa, as well as genetic vulnerabilities.
Temperamental factors
- People with anxiety disorders or obsessional traits in childhood are at greater risk of developing anorexia nervosa.
- Risk factors for developing an eating disorder include weight concerns, low self-esteem, depressive symptoms, social anxiety disorder, perfectionism and perceived stress.
Environmental factors
- Anorexia nervosa is more common in cultures and settings that value thinness. Internalizing a thin body ideal also increases the risk of developing bulimia nervosa.
- People who have experienced childhood sexual or physical abuse are at increased risk of developing bulimia nervosa.
Prognosis
- Retaining clients in treatment for eating disorders is difficult. About one-third of those with anorexia or bulimia nervosa relapse.
- Tailoring treatment to the individual ensures a more meaningful intervention.
- Early detection of an eating disorder is a predictor of better outcomes.
Evidence summary
Courbasson, C. & Shapira, L. (2012). In A. Khenti, J. Sapag, S. Mohamound & A. Ravindran (Eds.), Collaborative Mental Health: An Advanced Manual for Primary Care Professionals (pp. 143–178). Toronto, ON: Centre for Addiction and Mental Health.
Goldbloom, D. (2011). The patient with an eating disorder. In D. Goldbloom & J. Davine (Eds.), Psychiatry in Primary Care: A Concise Canadian Pocket Guide (pp. 129–144). Toronto, ON: Centre for Addiction and Mental Health.
Sullivan, P. (2002). Eating Disorders and Obesity. New York: Guilford.