Anorexia nervosa explanations

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  • 1. Anorexia NervosaBiological Explanations 1. Neural 2. Evolutionary
  • 2. - This means cessation -Excessive fear ofof menstrual periods. Fear of becoming fat. PeopleThe absence of three with anorexia are notconsecutive periods in weight gain simply obsessed withwomen who are of weight but fearful ofmenstruating age weight gain Amenorrhoea Anorexia Abnormal Nervosa Weight -People with anorexia do not see their own thinness. -Weight loss is They often continue to see considered abnormal themselves as fat despite when it drops below the fact that their bones Body image 85% of the individuals can be clearly seen. They distortion normal weight based on also often deny the seriousness of their low age and height body weight.
  • 3. A01 Neural causes - HDT RECAP: Lateral HypothalamusWhat are the neural and themechanisms involved in hunger Ventromedialand satiety? Hypothalamus Neural cause - Hypothalamus Lateral Hypothalamus Dysfunction Theory (HDT) – functions as the hunger centre When weight is low, the LH is activated. Ventromedial When weight is high, Hypothalamus – the VMH is activated. operates at the satiety centre
  • 4. A01 Neural causes - HDTHumans and other animals have a „set weight‟ (homeostasis) thatis correct for them, anyone who falls below this weight will feel hungry, and anyone who goes above it will eat less in order to regain „normal‟ weight Garfinkel & Gardner (1982) The hypothalamus is aDisturbed Hypothalamic function weight thermostatmeans that it doesn‟t keep weight at a „normal level‟ The VMH or LH might be constantly activated.Link to AN:The LH is damanged, causing the VMH to be over activated inresponse – body always belives it is overweight, resulting inrestricted eating
  • 5. Neural causes - HDT Lashley (1938) found that lesions to certain parts ofthe hypothalamus in rats causes changes in appetite and hunger – leading to starvation or excessive binging (depending on which part is damaged).This offers empirical support for the role of the brain in AN A02Also think back to: Hetherington & Ranson and Anand & Brobeck
  • 6. Neural causes - HDT A02Approaches: Can AN be Debates: Cause andbetter explained by the Effectbehavioural approach? Is the hypothalamus- Rise in media exposure, thin dysfunction the cause or therole models, modelling result (effect) of AN?programmes? Ethics: Non-human animals in research The animals used when testing HDT will have Issues: Ratomorphism suffered after the experiment due to the lesions made… Lots of evidence from non- human animal studies but humans don‟t necessarily Also, don’t forget..AO3.. How science works: work in the same way - Extrapolation -Laboratory experiments -Scientific measurements
  • 7. Neural causes - Serotonin A01 Think back: A neurotransmitter,What is serotonin? associated withWhat disorders is serotonin depression andassociated with? aggressive behaviourBailer et al (2007) compared serotonin activity in womenrecovering from restrictive type anorexia (restricted foodintake) and binge-eating/purging type (periods of restrictiveeating and binge/purge behaviour) with healthy controls. Theyfound significantly higher serotonin activity in the womenrecovering from anorexia. In addition, they found the highestlevels of serotonin in those with the most anxiety.
  • 8. Neural causes - Serotonin A02 Most research into the link between serotonin and AN are conducted on p‟s with an ongoing eating disorder – why might this be a problem?
  • 9. Neural causes - Serotonin A01 In PET scans, a drug is injected that binds with serotoninreceptors and when the brain scan is taken the drug shows upas brightly lit areas. These areas can then be measured and it gives an estimate of the number of serotonin receptors in different areas of the brain. Frank et al (2002) and Kaye et al (2005) conducted PETscans and have shown that there are fewer serotonin receptors in the brains of people with eating disorders.More importantly Kaye et al (2005) found that these changes are also found in people who have recovered from eatingdisorders – how can this be used to support a link between serotonin and eating disorders? A02
  • 10. Neural causes - Serotonin A02Approaches: Can AN be Debates: Reductionistbetter explained by thebehavioural approach? AN is caused by an issues with serotonin levels may just be a- Rise in media exposure, thin little to simplerole models, modellingprogrammes? Issues: Nomothetic Theory suggests that the causes of AN would be the same for each individual Debates: Deterministic however there are wide individual differences between this with AN It ignores the role of free will in eating behaviour Also, don’t forget..AO3.. How science works: -Laboratory experiments -Scientific measurements
  • 11. Evolutionary Explanations - AFFH A01 What does the Evolutionary Theory suggest about human behaviour? Good for Adaptive Survival Guisinger (2003)suggested that AN is a reflection of eating The EEA refers to the behaviour that was environment in which a adaptive in the species first evolved. environment ofevolutionary adaptation (EEA)
  • 12. Evolutionary Explanations - AFFH A01When a person begins losing weight, physiological mechanismskick in and conserve energy and increase the desire for food.However, in the EEA, extreme weight loss was due to severedepletion of local resources - this adaptation must be turnedoff so that individuals can increase their chances of survivalby migrating to more favourable (and more plentiful)environments.Therefore, the „switch‟ that increases desire for food andenergy conservation must be switched off so that migrationcan occur.If it is not switched off the individual will use resourcesforaging for food rather than planning a migrationfurthermore, the energy which is being conserved will beneeded for the move.
  • 13. Evolutionary Explanations - AFFH A01 Therefore the anorexic is able to „switch off‟ the desire forfood signals explaining how they are able to lose so much weight. The hyperactivity found in anorexics may be a form of “migratory restlessness” as many species increase activity in times of food shortage and prior to migration.
  • 14. Evolutionary Explanations A01 - Reproductive Suppression Argues that adolescent girls‟ desire to control their weight represents an evolutionary Surbey adaptation in which ancestral girls delayed the (1987) onset of sexual maturation in response to cues about the probability of poor reproductive success This is adaptive because itenables the female to avoid Don‟t forget what giving birth at a time when the Evolutionaryconditions are not conducive approach says to her offspring‟s survival about reproduction
  • 15. Evolutionary Explanations - Reproductive Suppression This model is based on Surbey argues that the the observation that in a anorexia is a “disordered number of species, variant” of the adaptive puberty is delayed or ability of females to alter suppressed in females the timings of when they are subjected reproduction at a time to stress or are in poor when they feel unable to physical condition cope with womanhood Don‟t forget what This hypothesis is supported by the observation that the Evolutionary menarche (the onset of puberty) is delayed in prepubescent approach saysgirls with AN and that amenorrhoea is a typical characteristic about reproduction of the disorder. This is because sexual maturity is suspendedin these women until the environment is more suited to raising children successfully.A02
  • 16. Evolutionary Explanations This hypothesis is able to explain some A02characteristics of AN effectively, i.e. their constant refusal to acknowledge their own hunger signalsAble to explain the genetic component in AN.Holland et al (1988) supports the idea that Anorexicbehaviour patterns enabled Anorexia suffers to surviveto reproduce and pass on such behaviours genetically.56% for MZ, 7% for DZHowever, this theory is unable to explain why girls are moreHowever, the Reproductive Suppression theory does do aaffected by AN than boys. Presumably, both genders wouldlittle in the way of making a suggestion as to the genderbe equally likely to benefit from the ability to ignoredifference in AN sufferers, but the evolutionary theoryhunger signals until they had moved on to more plentifuldoesn‟t explain why there are male AN sufferers at allland.
  • 17. Evolutionary Explanations A02Approaches: Can AN be Debates: Nature/Nurturebetter explained by analternative approach?- Rise in media exposure, thinrole models, modellingprogrammes? Issues: Unfalsifiable It is impossible to test the theory scientifically Issues: Lack of Issues: Lack of Evidence Evidence We have no direct evidence for this model It ignores the role of free will in eating behaviour Also, don’t forget..AO3.. How science works: -Difficulty testing
  • 18. Anorexia NervosaPsychological Explanations 1. Behavioural 2. Psychodynamic
  • 19. - This means cessation -Excessive fear ofof menstrual periods. Fear of becoming fat. PeopleThe absence of three with anorexia are notconsecutive periods in weight gain simply obsessed withwomen who are of weight but fearful ofmenstruating age weight gain Amenorrhoea Anorexia Abnormal Nervosa Weight -People with anorexia do not see their own thinness. -Weight loss is They often continue to see considered abnormal themselves as fat despite when it drops below the fact that their bones Body image 85% of the individuals can be clearly seen. They distortion normal weight based on also often deny the seriousness of their low age and height body weight.
  • 20. Behavioural causes A01 - Conditioning Learning RECAP: throughWhat is operant conditioning? association (positive and negative) Anorexic behaviour is reinforced in some way Compliments/attention Concern for losing for losing weight considerable weight becomes This makes the positive reinforcement and individual more likely again this makes the individual to repeat the more likely to repeat the starvation behaviour starvation behaviour
  • 21. Behavioural causes A01 - Conditioning Starts to alter eating behaviour (e.g. Dieting) Person feels good aboutthemselves – in control of Loses weight eating Reinforcement of behaviour (+ve & -ve)
  • 22. Behavioural causes A01 - Social Learning Theory RECAP: VicariousWhat is the Social Learning learningTheory? (through another person)Anorexia is learnt by observing others Role Model Observation Observation
  • 23. Behavioural causes A01 - Social Learning TheoryModelling – the behaviour and characteristics ofrole models are imitated If a famous person is seen as someone we wish to be like, we are likely to want to be very thin like they are We observe them receiving positive reinforcement for being thin, e.g. Fame, wealth and attention Makes the individual more likely to repeat the behaviour
  • 24. Behavioural causes A01 - Social Learning Theory ...because these This theory suggests cultures will be that AN will be more more likely to likely to occur in have thin role cultures that judge models –self-worth in terms of reinforcing the weight and shape weight loss Media portrayals of thin role models are also suggested to have Imagine a country where the phrase “You‟ve contributed to gained weight” is considered a compliment development of eating disorders
  • 25. Behavioural causes A02Approaches: Behavioural Issues: Deterministicapproach ignores cognitivefactors Suggests that anyone who have observed another being reinforced or who have- Behavioural approach been reinforcement themselves forunderplays the cognitive weight loss will develop an eatingaspects of AN, doesn‟t deal disorderwith the faulty perceptions ofbody image that are typicallycentral to the disorder Issues: Reductionist Reduces the complex nature of eating disorders to simple learning or response to a Issues: Cultural Bias compliment. Research conducted in Fiji and views eating behaviour from a Western Also, don’t forget..AO3.. How science works: perspective - Sample -Natural experiments
  • 26. Psychodynamic Explanations A01 Think back:What are the main aspects of the Unconsciouspsychodynamic approach? processes 1. Control 2. Fear of growing up 3. Family systems approach
  • 27. Psychodynamic – Control A01 Bruch (1973) suggested that AN was an attempt by the individual to exert some controlIndividuals with AN at some point struggled for autonomy and the need to be independent from parentsThis theory suggests that sufferers of AN discovered their eating behaviour was one area of their life that they could control – increasing autonomy and self-efficacyThink back to Maslow and the hierarchy of need – does this contradict the DIMH theory? A02
  • 28. Psychodynamic – Control Romans et al (2001) –Found evidence for a linkbetween childhood sexual abuse and thedevelopment of an eatingdisorder. They found that early maturation and parental over-controlwere risk factors for AN A02
  • 29. Psychodynamic – Fear of Growing Up A01Crisp (1980) developed theories as tot he cause of AN basedon the fact that self-starvation and loss of body weight led to the postponement of menarche or the loss of menstruation (amenorrhoea) Crisp suggested that this was an unconscious attempt by thegirl to remain pre-pubescent, postponing the onset of adulthood and therefore remaining in need of parental careAN allows its sufferers to look child-like (amenorrhoea, breasts stop developing) maintaining the illusion that they are still a child. Freud went on to extend the theory suggesting that eating was a substitute for sexual activity – not eating is a way to repress sexual thoughts, starving to remain pre-pubescent and sexually immature
  • 30. Psychodynamic –Fear of Growing Up Romans et al (2001) – Found evidence for a link between childhood sexual abuse and the development of an eating A02 disorder. They found that early maturation and parental over-control were risk factors for AN
  • 31. Psychodynamic – Family Systems Approach A01 Minuchin, Rosman & Baker (1978) attempt to explain AN by using a family focussed approachThis theory suggests that a child develops AN as an attempt to divertattention away from other family problems – in a misguided attempt to keep the family together For example – in cases where the parents were Removing the parents having relationship from their own issues withproblems, the AN sufferer each other – the ultimatehopes that their illness will aim is to postpone a create a common goal for separation. the parents
  • 32. Psychodynamic explanationsApproaches: Can AN bebetter explained by an Debates: Free will A02alternative approach? The Psychodynamic explanations ignore the role-Behavioural (learning) that free will can take in AN-Biological (genetics) Issues: Lack of evidence Lack of objective evidence, the unconscious cannot be Issues: Unfalsifiable observed, measured or tested. Cannot be proven to be true or false Also, don’t forget..AO3.. How science works: -Lack of scientific measurements