5.3.2 Biological Explanations

• What is anorexia nervosa characterized by?

  Persistent restriction of energy intake
• One of the key diagnostic criteria for anorexia nervosa is significantly low body weight
• Match the subtype of anorexia nervosa with its description:

  Restricting Type ↔️ Weight loss through dieting

  Binge-Eating/Purging Type ↔️ Episodes of binge eating or purging
• Heritability estimates for anorexia nervosa range from 33% to 84%.
• Genes involved in serotonin regulation may contribute to anorexia nervosa
• Which gene variations are linked to anorexia nervosa?

  Brain-derived neurotrophic factor (BDNF)
• Twin studies highlight the genetic component of anorexia nervosa.
• Genetic factors interact with environmental factors to influence the development of anorexia
• Heritability estimates for anorexia nervosa range from 33% to 84%
• Genetic factors involved in serotonin regulation may contribute to anorexia nervosa.
• What role does BDNF play in anorexia nervosa?

  Linked to gene variations
• Twin studies show that if one identical twin has anorexia nervosa, the other twin is more likely to develop the disorder
• Genetic factors interact with environmental factors in the development of anorexia nervosa.
• What is the range of heritability estimates for anorexia nervosa?

  33% to 84%
• Match the genetic factor with its role in anorexia nervosa:

  Serotonin regulation ↔️ Genes involved in mood and appetite

  BDNF ↔️ Variations linked to the disorder

  Estrogen receptors ↔️ Genetic variations may play a role
• What are the defining characteristics of anorexia nervosa?

  Low weight, fear of gain
• In the restricting type of anorexia nervosa, weight loss is achieved through dieting, fasting, and excessive exercise
• What behaviors characterize the binge-eating/purging type of anorexia nervosa?

  Binge eating or purging
• Neurochemical imbalances in anorexia nervosa affect mood, appetite, and cognitive processes.
• What is the impact of low serotonin levels in anorexia nervosa?

  Increased obsessive behaviors
• Imbalances in ghrelin and leptin in anorexia nervosa can lead to abnormal hunger and satiety cues
• Match the brain difference with its impact in anorexia nervosa:

  Reduced gray matter ↔️ Affects cognitive processing

  Altered neural activity ↔️ Affects emotional regulation

  Dopamine-mediated reward pathway ↔️ Reduced pleasure from food
• What are the defining characteristics of anorexia nervosa?

  Low weight, fear of gain
• Hormones such as leptin and ghrelin play a key role in regulating appetite in anorexia nervosa.
• Lower levels of estrogen in anorexia nervosa contribute to mood changes and menstrual irregularities
• What is a limitation of biological explanations for anorexia nervosa?

  Neglects psychological factors