Serotonin - disturbances in serotonin levels are characteristic of those with eating disorders, namely anorexia nervosa - persistent disturbances in serotonin levels leads to increased anxiety which can trigger anorexia
Dopamine - increased dopamine acitvity in the basal ganglia associated with anorexics (where the brain responds to pleasure) - anorexics find it difficult to associate good feelings with the things people normally find pleasurable, for example food
Serotonin - Bailer - high levels of serotonin in AN patients with binge/purge tendancies when compared to a healthy control group - higher levels of serotonin in individuals with anxiety - supports idea that constant disruption of serotonin levels influences increase in anxiety which could then trigger AN. Kaye - SSRI's (alter levels of serotonin) were ineffective when used with recovering AN patients. Possible that malnutrition changes in the body of AN's may negate the functioning of SSRI's so they may only be used when weight returns to a normal level.
Dopamine - Kaye - PET scans (scientific method) on 10 patients recovering from AN and 12 healthy controls - increased levels of dopamine in the basal ganglia found in the recovering AN's - supports idea that an increased activity of dopamine is linked with the development of AN. Castro-Fornieles - adolescent girls with AN had higher levels of HVA (waste product of dop).
Treatment - people realise they are dealing with a dysfunctional biology which is treatable rather than a dysfunctional family which often is not. So it reduces the guilt generated by the view that it is parents who cause the development of eating disrders in their children.
Element in flaws on the supporting studies - samples in the research into AN only used a small amount of pp's from mainly Western cultures which were al female - introduces gender bias as it is statistically known that males also suffer from eating disorders (25%) - element of ethnocentricity as it assumes all anorexics from various cultures will show those characteristics of the Western culture - these two elements reduce population validity and so generalization is limited.
Gender bias - most research into females with AN - males cannot be assumed to have the same results as females do as we are physiologically different - so inaccurate to assume changes in serotonin/dopamine levels cause the same effect on males as they do females.
Validity of biological approach to AN questioned as there are methodological issues arose - we cannot be sure that increased anxiety/inability to associate food with pleasure are seen by all people experiencing imbalances in neurotransmitters.To overcome this research needs to use a wider range of research such as studies into males and non-Western cultures to increase validity of the biological approach.
Scientific methods - Use of PET scans allow hypothesise to be scientifically testen and proven unlike psychology explanations which are not backed up via scientific/testable data.
Evolutionary approach to AN AO1
Reproduction suppression - assumes adolescent girls have a desire to control their weight as it is an evolutionary adaptation where ancestral girls delayed the onset of their sexual maturation in response to cues about poor reproductive success such as a harsh environment. Observations back this up as females who are experienced to stress or in poor physical condition, puberty is delayed. So this approach could help to explain why modern girls may feel that they are unable to cope with becoming an adult or is undergoing stress - therefore AN may develop as an emergency coping mechanism to deal with these feelings.
Adaptive to flee famine hypothesis - typical characteristics of AN - hyperarousal, food restriction, weight loss could be seen as adaptations of our ancestral women who, when under times of poor conditions had the need to migrate to a different environment with better quality food supplies had to suppress the onset of their sexual maturation as reproducing would be likely to be unsuccessful. Normally, when you restrict yourself from eating your body automatically starts to conserve food and has the drive to consume food. So these women had to have the adaptive ability to 'turn off' this drive for food until they migrated to a more suitable environment.
Ammenorrhea - as ammenorrhea is a typical symptom of anorexia, it means that this adaptive of suppressing menstration is displayed in anorexics who have effectively suspended reproduction.
However if anorexia is an adaptive trait then how come it is a known consequence that when you delay the onset of menstration it is due to the lack of nutrition you are gaining from food. Anorexia therefore reduces fertility and makes reproduction harder and sometimes it can also be fatal. So therefore if this was the case it would not have been likely to be passed on genetically as it would be difficult for the anorexics back then to reproduce.
Subjective - does not have a factual basis and is highly subjective - theories based on individual views so it is difficult to back up this explanation with facts.
Cause and effect impossible - complex disorder - can't exclude social + cognitive influences - evolutionary approaches can never be tested so a cause and effect relationship can never be established.....
As you can't exclude social + cognitive influences this weakens the evolutionary explanation as it suggests that there are other factors involved in the development of AN and the reproduction suppression and adaptive to flee famine hypothesis are not the only causes.
IDA evolutionary approach to AN
Reductionist - only biological explanations are considered. We know anorexia is a complex disorder where a range of influential factors are involved such as emotional and psychological aspects. The biological approach attempts to simplify the explanation which could be seen as an advantage as it helps us understand the explanation however it is a complex disorder and other factors should be addressed as it is a complex phenomenom. Can't establish a paradigm as other approaches (psychological) has been ignored.
Holistic approach been more suitable? it would consider how differing factors interact together to cause AN. Would result in more effective and appropriate conditions being established for those with the condition and so improve their chances of making a full recovery as various treatements could be used.