PSYX 340 Psychological Disorders · Unit 2: Mood, suicide, body and addiction · on Exam 2
2.5 Eating disorders
Study notes for Eating disorders in PSYX 340 Psychological Disorders at Montana State University: the big ideas, a worked example, common mistakes and an exam tip. The same topic has endless practice questions and flashcards in Mathub.
Big ideas
- Anorexia nervosa: restricting food leads to significantly low body weight, with intense fear of gaining weight and a distorted view of body shape or weight. Types: restricting and binge-eating/purging. Adult severity uses BMI: mild 17 or above, moderate 16–16.99, severe 15–15.99, extreme below 15. It carries the highest death rate of the eating disorders.
- Bulimia nervosa: recurrent binges (a large amount of food in a short time with a sense of losing control) followed by compensatory behavior (vomiting, laxatives, fasting, excessive exercise), both at least once a week for 3 months, with self-worth tied to shape and weight. Weight is often in the normal range.
- Binge-eating disorder: recurrent binges at least once a week for 3 months with marked distress, but without regular compensatory behavior. It is the most common eating disorder. ARFID (avoidant/restrictive food intake disorder) involves restricted eating without body-image concerns.
- Explanations form a multidimensional risk picture: psychodynamic and cognitive factors (Hilde Bruch’s ideas about ineffective parenting and a lack of self-awareness), depression, biological factors (the hypothalamus and weight set point, genetics, serotonin), societal pressure toward thinness, family environment, and racial, cultural and gender differences.
- Treatment: first restore weight and nutrition when health is at risk, then address thinking and relationships. Family-based treatment (the Maudsley approach) has strong support for adolescents with anorexia; CBT is the leading treatment for bulimia and binge-eating disorder; antidepressants help some bulimia cases.
Worked example
An adult is 1.70 m tall and weighs 44 kg and restricts food intensely. What is the BMI and the DSM-5-TR severity?
Show the solution
BMI = kg / m² = 44 / 1.70² = 44 / 2.89 ≈ 15.2. That falls in 15–15.99, so the severity specifier is severe.
Common mistakes
- Assuming everyone with bulimia is underweight. Most are near a normal weight; low weight with binge-purge behavior points to the binge-eating/purging type of anorexia.
- Forgetting that binge-eating disorder has no regular compensatory behavior.
- Using “once a week for 3 months” for anorexia. That frequency rule belongs to bulimia and binge-eating disorder.
Exam tipSort the three by two questions: is weight significantly low (anorexia)? If not, is there regular compensation (bulimia) or not (binge-eating disorder)? Practice BMI arithmetic for the severity question.
Keep going in Mathub
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