Lecture 3 - Eating disorders

disordered eating

• food choices strongly influenced by desire to maintain a certain weight or body type

• often feel guilt around eating certain foods

• some avoidance of or difficulty with eating in social situations

eating disorder

• food choices influenced by goals of restricting, losing weight, binging

• feel guilt and shame around food most the time

• frequent avoidance of eating or attending social situations involving food

ED types

1. anorexia nervosa (AN)

2. bulimia nervosa (BN)

3. binge eating disorder (BED)

4. avoidant restrictive food intake disorder (ARFID)

5. less common types

anorexia nervosa

• refusal to maintain body weight (self-starvation)

• at least 15% below normal weight with an intense fear of weight gain

• disturbance of body image

• gas the highest mortality rate of any mental disorder. Causes of death:

  • malnutrition

  • suicide

  • drug and alcohol

  • diabetes

bulimia nervosa

• loss of control, overeating

• bingeing/purging cycles - vomiting, laxative misuse

• often involves over exercising

binge eating disorder

• recurrent episodes of binge eating with a lack of control over eating

• binge eating episodes are associated with 3 or more of:

  • eating much more rapidly than normal

  • eating until uncomfortably full

  • eating large amounts of food when not hungry

  • eating alone because of feelings of embarrassment

  • feeling disgusted with the self

avoidant restrictive food intake disorder

• severe restriction of types or amount of food eaten

• lack of appetite or interest in food

• dramatic weight loss

• upset stomach, abdominal pain, or other gastrointestinal issues with no other known cause

• limited range of preferred foods that becomes even more limited

• no fear of weight gain or body image disturbance

less common types

• atypical AN - same symptoms but medium or larger bodies despite severe food restriction

• OFSED - present some symptoms of the others but does not meet the full criteria

• pica - persistent eating of non-food objections ie chalk, paint, stones

• rumination disorder - persistent regurgitation of food

the transdiagnostic approach

shows it is common for EDs to shift overtime

common features of EDs

• extreme concern about eating, weight and shape; repeated body checking or avoidance

• weight loss/gain

• strict dieting and preoccupation with food

• loss of control over eating

the over-arching aspect is that their self-worth is largely or exclusively dependent on eating, shape and weight and their control

minnesota starvation experiment

fit, young male volunteers

• 3 month control - participants ate normally

• 6 month semi-starvation period - caloric intake reduced by 50%

• 3 month recovery - participants were re-nourished

  • results - physical, emotional, cognitive and social changed. ED attitudes and behaviours

 

etiology

1. genetics

2. neurobiological factors

3. sociocultural influences

4. psychological and dispositional factors

genetic influence

• twin studies - 58 to 88% increased chance

• interaction of genetic dispositions and individual experiences

• first degree relatives of clinical cases of AN have x11 risk of AN

neurobiological factors

• brain and serotonin function leads to changes in appetite, mood and impulse control in EDs

• hippocampus volume impairment is involved in AN - shows a marked volume reduction which is reversible with weight restoration