anorexia

What is anorexia

ED characterised by persistent low body weight

Anorexia symptom criteria :

• restriction of energy and low BMI measuring 17kg/m or less

• Fear of gaining weight

• Distortion in body image

Features of anorexia

• 2 subtypes : restricting type = dieting or excessive fasting and purging = lots of eating but then self induces vomiting

• Anorexia is diagnosed significantly more in females than males

• The prevalence is higher in high income countries that are highly industrialised like the USA and European

Biological explanations = Genetics

Scott-Van Zeeland - when comparing different gene samples of AN women and a control, he found differences in the EPHX2 Gene which is associated with production of an enzyme to metabolise cholesterol (the disorder may be caused by how the body processes cholesterol affecting mood and hunger behaviour) , AN patients have higher cholesterol considering them highly malnourished

Evaluation of genetics

Supporting - there may be multiple factors that work together to cause the illness. But other societal or cultural factors may increase the risk of developing which could be evidence of certain gene markers trigger the illness, there is evidence of people with relatives with anorexia have increased risk

Weakness - however it can’t be ignored that family memeber live in a shared environment and so influence of external factors could equally account for the symptoms and perhaps the behaviour patterns are being learned through observation of the diagnosed individual

How can the prevalence in relatives explain AN?

11.3X more likely to develop with AN relative

How can dopamine and serotonin explain AN?

Increased serotonin creates anxiety meaning eating related neural information is not transmitted. lack of DA means lack of reward for eating behaviour

How can the EPHX2 Gene explain AN?

Regulates cholesterol metabolism, people with AN have high level level of cholesterol, it disrupts the metabolism of cholesterol and other fatty acid

How can the ITPR3 explain AN

Involved in detetcing tastes. Causing a genetically determined dysfunction of tastes - they don’t eat food that doesn’t taste nice

What did Scott Van Zeeland find

Variants in the EPHX2 gene may increase susceptibility to AN

What did Holland finds

Higher concordance rate for AN in MZ twins than in DZ twins, Indic that identical twins were for more likely to both have AN - AN is polygenetic disorder so it’s more genes acting not just 2

How could drug therapy work to treat AN?

SSRI & Olanzipe regulate serotonin & Dopamine

SSRI increase dopamine , antidepressants, increase serotonin and DA

Olanzipes decrease serotonin, Antipsychotic → Boosts DA, decrease serotonin

How would GENE modification work to treat AN

Modify the level of EPHX2 & ITR£ before birth during development

How would CBTe work to treat AN

Challenge and modify irrational beliefs using cognitive and behaviour interventions (homework)

→ not a talking therapy, clinician would highlight the problem and change it, do not need drug pre CBT