Anorexia Nervosa

Genetic Explanations - Twin Studies

Holland - 45 Female twins, concordance of 56% MZ, 5% DZ (presence of anorexia in both)

Genetic Explanations - Candidate Genes

Zeeland: 1205 AN and 1948 control, sequenced 152 candidate genes, epoxide hydrolase significantly associated with AN. Codes for enzyme involved in cholesterol metabolism

Genome Wide Association Studies - Genetic Explanations

Boraska: 5551 people with AN and 21080 matched controls. 72 separate genetic variations were identified, none were significantly related to AN - study not sensitive enough to detect genes

Neural explanations - Serotonin

measure metabolite 5-HIAA
Bailer/Kaye - low levels of 5-HIAA in people with AN. these levels return to normal after short term weight recovery, and increase beyond normal levels after long term recovery

Neural Explanations - Dopamine

Metabolite HVA

Kaye - lower HVA levels in recovered AN patients compared to controls
Bailer - injected amphetamine (dopamine drug). Control ppts experienced euphoria, AN experienced anxiety levels instead. Eating increases dopamine

Genetic Explanations AO3 (General)

twin studies assume exact same environments - MZ twins often treated more similarly than DZ do.
The inability to clearly find one gene in multiple studies suggests AN is polygenic. Many genes make important but modest contributions
limited as does not consider diathesis stress. stressors needed to cause the predisposition to actually result in AN - environment more important

Neural Explanations research AO3

Kaye - compared women diagnosed with AN with controls, HVA levels of women with AN were 30% lower than non AN women
Nunn - serotonin on its own does not distinguish having/not AN. Better explained by its interactions with Noradrenaline and GABA. Neurotransmitters do not operate in isolation

Neural Explanations AO3 General

drug treatments targeting low serotonin (SSRI) or dopamine can be developed. Current drugs may help prevent relapse. (63% do not relapse compared with 16% not taking SSRI - Kaye)

Family Systems theory by who

Minuchin

FST 4 parts

1. enmeshment - boundaries become ‘fuzzy’

2. overprotectiveness - no room for independence

3. rigidity - denying need to change/work hard to maintain things as is

4. conflict avoidance - suppress or avoid

Bruch suggests AN occurs when daughter struggles to achieve autonomy and control she craves. this leads to confusion.

FST confusion traits

distorted body image, an inability to identify internal body states such as hunger, overwhelming feeling of a loss of control. The more weight lost, the more her ‘degree of control’

FST research

Strauss, Ryan - women aged 16-31 vs controls, those with AN had greater disturbances of autonomy than control, had more enmeshment, perceived poorer communication within their families
       |Aragano - 30 Portuguese women treated for eating disorders, they were no more enmeshed/rigid that a sample of non-eating disordered families
Davis - found that family interactions affecting eating disorders only occurred in adolescents with high levels of anxiety (mediating factors are involved)

Validity of FST

FST explains the large ratio of 9:1 women to boys AN prevalence
However, struggles to explain existence of AN in boys and completely ignored role of fathers in family dysfunction

SLT and AN

modelling - template for behaviour such as a cartoon character/family/celebrity
vicarious reinforcement - if model is praised
role of the media - the ideal has been thinner and thinner “size zero” vicarious reinforcement via fame, success, wealth, respect, satisfaction of female role models

SLT Dittmar

Barbie, if human sized, would have a waist 39% smaller than women with AN
162 British girls between 5-8 were exposed to images of either Barbie, Emme (realistic body type), or control (flowers/balloons/clothes), the girls then rated statements about body esteem such as “I’m pretty happy with the way I look”, they then coloured in two body silhouettes, one current and one ideal
the girls who saw barbie were significantly more dissatisfied with their body shapes and had lower body self esteem

SLT - research

Becker - 63 adolescents in Fiji completed the EAT-26 questionnaire in 1995 when TV broadcast was first introduced. Another 65 girls completed it 3 years later. in 1995, 13% showed high score indicated eating disorder risk, which increased to 29% 3 years later
     |two different girls, no test for pre tv exposure
Chisuwa, O’Dea - longitudinal study over 40 years, traditional values favouring plumpness replaced by individualist cultural thinness ideals. Media has an influence

SLT general AO3

SLT has not led to effective therapies. On its own, replacing with a positive model is not effective. Other therapies better - drug therapies/cognitive therapies
If social learning was responsible, we would expect many cases, therefore other factors involved. Perhaps biological/environmental vulnerability (diathesis)

Cognitive explanations 3 factors

disturbed perception - preoccupations with food, weight body shape, misinterpreting emotional states as feeling fat (e.g. anxiety)

irrational beliefs - all or nothing, catastrophising, perfectionism

cognitive inflexibility - cognitive interpersonal maintenance model suggests people with AN have problems set-shifting

disturbed perceptions research

Williamson - 37 ppts with AN used body image assessment to estimate current and ideal size, those with AN were significantly less accurate in estimates than control, and their ideal was significantly thinner than controls
Sachdev - scanned brains of ppts and controls, and when shown images of self, attention areas of brains had little activation vs. controls who had activation. cognitive distortion as not reacting normally
Cornelissen - 30 women with and 137 without AN adjusted a computerised image to match body size, and found no significant difference between the groups of women and estimated vs actual BMI

perfectionism research

Halmi: 728 over 16 took SIAB questionnaire and EATATE interview. This measures indicators of perfectionism in childhood and this was associated with current AN symptoms
|retrospective inaccurate

Cognitive causation

cognitive argues the factors cause AN rather than factors being byproduct