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PIP - Eating disorders - Coggle Diagram
PIP - Eating disorders
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Anorexia nervosa
DSM-5 criteria -
- Low weight < 85% of expected
- Intense fear of gaining weight / fat
- Disturbance in perception, experience or evaluation of weight / shape
- Subtypes -
-> Restricting - severe dieting, fasting and exercise
-> Bingeing / purging - vomiting, laxative misuse, etc
- Lifetime prevalence - 0.5%-1% (10% of ED cases)
Bulimia nervosa
DSM-5 criteria -
- Recurrent binge eating, including loss of control
- Inappropriate weight and compensatory behaviours - both at least once a week
- Weight / shape concerns unduly influence self-evaluation
- Does not meet AN criteria
- Subtypes -
-> Purging - self-induced vomiting, laxative misuse
-> Non-purging - fasting and excessive exercise
- Lifetime prevalence - 1-3% in women (40% of ED cases)
Bulimia is often comorbid with substance abuse, anxiety and depression
- Also commonly comorbid with anorexia, with unpleasant cognitions being based on unpleasant thoughts about gaining weight
Possible causes of eating disorder onsent and maintenance, including the role of personality
Aetiology - biological factors -
- Genetics -
-> Relatives of people with EDs are 6x more likely to develop one
-> Heritability may be over 50% (Klump et al, 2011)
- Neurobiology -
-> Low serotonin levels (linked to depression/OCD comorbidity)
-> Hypothalamus (linked to appetite)
-> Inconsistent evidnece
- Some genetic evidence and some biological, but causality is hard to establlish as neurobiological function may be impacted by the disorder, rather than these neurobiological functions causing the symptoms
Aetiology - environmental factors:
- Culture - Western society (shape ideals, media and peers)
- Family - family system theory (Minuchin et al, 1975) - enmeshed, overprotective, rigid, poor conflict resolution
-> Symptom bearer or carrier of dysfunctional family with high expectations, over-control and poor emotional openness, typical of middle class families
-> Childhood abuse (Johnson et al, 2022)
-> Maternal eating habits
- Professions - ballet/dance, fashion, any context excessively valuing appearance, with average BMI being close to AN criteria
Aetiology - personality (Cassin et al, 2005; Lilenfield et al, 2006):
- Especially true for chronic cases - poor emotion reguation, intolerance of mood and low self-esteem and self-worth
- Neuroticism
- Perfectionism
- Insecure attachment
- Slightly different factors in AN and BN
-> AN - need for control, persistence, comorbid with OCD and OCPD
--> Perfectionism requires persistent dieting - frontal lobe dysfunction
-> BN - impulsivity, sensation-seeking
--> Comorbid with substance abuse and BPD
--> Poor impulse control and idea of being 'hooked' on food - shares aetiology with addiction and some have other substance misuse issues
Cognitive behavioural model - Williamson et al, 2004:
- Psychological risk factors ->
- Internalised thin ideal
- Traits - perfectionism and need for control
- Fear of fat
- Self schema - negative, self-esteem, contingent on shape
- Cognitive biases - preoccupation, distorted body image
- Leads to dietary restraint and negative emotions (which can reinforce bias) and both lead to binge eating, which informs the ED behaviour
- ED behaviours - body checking, restrict eating, compensatory behaviour
- This ED behaviour then reinforces the psychological risk factors and views of the self
- When under stress, ED behaviours are driven more strongly, and bring about negative emotions which fuel behaviours more
Evidence for the role of stress - Sassaroli & Ruggiero (2005):
- Female pupils completed questionnaires on a typical day and an exam day (stress condition)
- Parental criticism, worry and perfectionism -> bulimia
- Perfectionism and low self-esteem -> drive for thinness
Social dimensions -
- Conflict between fashion ideals and reality
- Influence of family and eating practices at home
Biological dimensions -
- Hormone imbalances and genetic patterns of biological vulnerability
Psychological dimensions -
- Warped perception of body image triggered by misattribution of events of eating
An integrative model -
- Biological influences = inherited vulnerability unstable or excessive neurobiological response to stress associated with impulsive eating
- Social influences = cultural pressure to be thin and family interaction and pressure
- Psychological influences = anxiety focused on appearance and presentation to others and distorted body image
-> All lead to restriction of eating
-> This then leads to anorexia = binge or construct restriction -> purge -> reduced anxiety
--> This then reinforces the restriction as drive reduction
-> Or leads to bulimia = binge eating -> purge -> reduced anxiety
--> Reinforces behaviour
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Summary
- Eating disorders are best understood from biopsychosocial perspectives
-> Insecure attachment and personality may provide diathesis
-> Stress may trigger onset
-> Cognitive behavioural model may explain maintenance
- Treatment differs by ED but may combine healthcare, medication, CBT and family therapy
Obesity
- Cultural norms encourage high fat foods, combined with genetic and environmental factors cause obesity - also an element of addiction
- It is difficult to treat, using professional directed behaviour modification programs, emphasising diet and exercise are moderately successful but prevention effort in changes to government policy on nutrition is more promising
- Involves syndromes of binge eating