Anorexia - Biological

Question 1

Anorexia

Answer 1

A type of eating disorder where despite the individual being under weight , fears that they might become obese so engages in self starvation to prevent it

Question 2

Diagnosis

Answer 2

Being diagnosed with AN a personal must display

• Persistent restriction of energy intake
• An intense fear of gaining weight or persistent behaviour that interferes with weight gain
• Persistent lack of recognition of seriousness of low body weight

Question 3

2 types

Answer 3

1. Restricting type : where a person severely restricts their food intake
2. Binge eating/ Purging type: Restricts food intake but may regularly engage in binge eating or purging behaviour ( self induced vomiting)

Question 4

Strober et al (Family study)

Answer 4

Research has found first degree relatives of individuals with AN have approx ten times greater risk of having AN than unaffected individuals

Question 5

Thornton et al (Twin study)

Answer 5

Comparing the similarity of MZ twins to DZ twins provides a measure of genetic + environmental factors in the development of AN ; twin studies generally suggest moderate to high heritability of AN - estimates vary between 28% and 74%

Question 6

Klump et al (Adoption studies)

Answer 6

Studied 123 adopted sibling pairs and 56 biological ones + assessed eating disorder symptoms ; heritability estimates ranged from 59% to 82% for different aspects of disordered eating

Question 7

Serotonin

Answer 7

Disturbance levels in serotonin appear to be a characteristic of eating disorders
Bailer et al measured serotonin activity in women recovering from AN and compared with healthy controls - found higher serotonin activity in binge eating/ purging women compared to other 2 groups

Question 8

Dopamine

Answer 8

Studies suggest a role for dopamine in AN
Kaye et al used a PET scan to compare dopamine activity in the brains of 10 women recovering from AN + 12 healthy women - In AN women found overactivity of dopamine receptors in the basal ganglia which appears to change the way people interpret rewards; explains why those with AN find it difficult to associate good feelings with food

Question 9

Limbic system dysfunction

Answer 9

Research suggests (Lipsman et al)the neural roots of AN appear to be related to a dysfunction in the limbic system in the brain - dysfunction in certain areas where normal functioning is to regulate emotion can lead to deficits in emotional processing which then lead to pathological thoughts and behaviours that are typical of AN

Question 10

*Evaluation - Genetics

Heritability

Answer 10

Fairburn et al says despite evidence from studies of a genetic component heritability of AN is unknown ; these studies have been inconsistent in estimates giving contradicting ranges + many also assume MZ and DZ twins raised in the same homes have the same experiences yet research found MZ twins are treated more similar than DZ

Question 11

Role of media

Answer 11

Genetic explanations suggest environmental factors such as the media do not play a role in AN however Bulik suggests genetically vulnerable individuals might seek out images of thin models in the media to reinforce their body image therefore maintain their AN

Question 12

*Evaluation - Neural explanations

Serotonin Limitation

Answer 12

SSRISs which alter levels of serotonin are ineffective when used on AN patients
Ferguson et al found no difference in symptom outcomes between patients taking SSRIs and those who were not however when used on recovering patients prevented relapse (Kaye et al)

Question 13

Dopamine Support

Answer 13

Research has shown support for the role of dopamine in AN as food aversion, weight loss, menstrual dysfunction have all been found to be related to increased activity in dopamine pathways (Kaye et al)