Anorexia Nervosa

A2 psychology revision - explanations of 1 eating disorder

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  • Created by: Maisie
  • Created on: 17-06-11 09:33

Clinical Characteristics

Anxiety - excessive fear of becoming fat

Weight drops below 85% of expected weight for age & height

Body image distortion

Amenorrhoea (menstruation stops)

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Genetic Explanation

1st degree relatives have increased risk

Holland et al: 56% concordance in MZ twins (7% in DZ's)
Nature vs. nurture - twins also share same upbringing & family environment
McCelland & Crisp: AN higher in class 1 &2 -> social class important
Immigrants to Western societies develop anorexia whilst relatives who remain at home do not
Bulik et al: recent review of twin studies shows genetic contribution to be 50-80%
Grice et al: susceptibility of AN found on chromosone 1 but unlikely to be caused by 1 gene alone
Genetics do play a role but small samples lack reliability, there is a culture bias in studies & no indication of exactly what is inherited
Recent dramatic increases in AN means genes are likely to provide a predisposition (diathesis-stress model)

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Evolutionary Explanation

1) Adapted to Flee Famine Hypothesis (AFFH)
Guisinger: AN is a reflection of behaviours that were adaptive - food, restriction, hyperactivity, restlessness & denial of starvation reflect adaptive mechanisms
Hyperactivity could = 'migration restlessness' (seen in many species)
Those with genetic predisposition today may trigger this adaptive mechanism
Hyperactivity not always shown in anorexics
Speculative theory -> unfalsifiable
Why do mainly young women suffer? - all ages & genders would have needed to flee famine

2) Reproductive Suppression Hypothesis (RSH)
Surbey: adolescent girls desire to control weight reflects an evolutionary adaptation to delay sexual maturity
Wasser & Barach: if women gave birth during famine, the child may not live or pressure may be put on the little resources available
Anderson & Crawford: agreed lack of menstruation in anorexics is an evolutionary adaption
Gender bias: what about anorexia in males? (& in menopausal women)
Does this really explain the cause? - what about function of characteristics? - are they adaptive?

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Neural Explanation

1) Serotonin
Bailer et al: significantly high serotonin activity found in those recovering from binge/purge subtype - those with highest had most anxiety (could be constant disruption causes anxiety = vicious cycle)
Correlational data - can't determine whether this is a cause or effect of AN
SSRI's not effective in treating anorexics
Kaye et al: SSRI's effective in recovering anorexics to prevent relapse

2) Dopamine
Kaye et al: overactivity in anorexics in basal ganglia (associated with interpretation of harm/pleasure)
Cause or effect of anorexia?
Gender bias in research - Kaye et al looked only at women

3) Noradrenaline
Halmi & Yum: disturbance to noradrenaline in anorexics -> influences eating
Cause or effect - unlikely that 1 neurotransmitter causes AN

4) Hypothalamus
Damage to LH = undereating (research support from studies relating to neural control of eating)
Evidence mainly from animals - issues of extrapolation

5) Neurodevelopment
Lindberg & Hjern: premature birth related to AN - reduced oxygen to brain

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Behaviourist Explanation

1) Classical conditioning: eating associated with anxiety - losing weight ensures anxiety is reduced
Could also associate slimness with attractiveness

2) Operant conditioning: food avoidance to get rewards - e.g. compliments - which reinforce behaviour, leading to continuation
Could also gain reward from feeling in control
Not all dieters become anorexic - OC doesn't explain why
Negative attention - would this be reinforcing?

3) Social learning theory: imitation of people they admire
Female role models in media are often rewarded from being slim & attractive - trying to copy = vicarious reinforcement
Groesz et al: media beauty ideal causes dissatisfaction which contributes to development of AN - effect most marked in U19's (BUT even though majority are exposed, not all people develop anorexia)
Hoffschire: media has preoccupation with thin body shape
Thompson: pressure from media encourages more & more dissatisfaction
Harrison: peers also voice admiration - pressure given indirectly & explicitly
Alberg: high incidence of AN in ballet dancers & models
Fearne: natural experiement - incidences of eating disorders in Fiji increased after introduction of US TV shows (issues of control with natural experiment - reliability?)

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Psychodynamic Explanations

1) Freud: eating & sex symbolically linked
Crisp: refusal to eat = attempt to remain in pre-pubertal state & postpone adulthood
Also suggested pregnancy & fat stomach unconsciously linked in anorexic mind
Halmi: menstruation ceased before significant weight loss in 40% of cases - cause or effect?

2) Sexual abuse: AN may be a response to early trauma
Carter et al: 48% of 77 anorexics reported childhood sexual abuse
Therefore anorexia may be an unconscious desire to destroy own body
Those who aren't abused? & those who are but don't develop AN

3) Bruch: effective & ineffective parents
Children of ineffective parents = confused about internal needs & become overly reliant on parents
In adolescence, a desire to become autononmous cannot be obtained - so take excessive control of body shape/size
Steiner et al: parents of anorexic adolescents had tendency to define child's physical needs (cause or effect?!)
Bruch: many of these parents anticipated child's needsFamily therapy has been shown to be effective
Helpful? - puts blame with family

4) Minuchin: family systems approach
Anorexics experience enmeshment - unable to become independent

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