bio cause of AN

Question 1

A01.1 - adoption studies / twin studies

Answer 1

adotion studies can be used to to explain the biological nature of AN as they seperate natureand nurture therefore any differences e.g. one has SZ the other doesnt is due to enviro but similarities due to genetics

twin studies can also be used
MZ twins share 100% of their DNA whereas DZ only share 50% if its due to genetics then concordance rates would be significantly hugher in MZ twins but

Question 2

A03.1 strength

Answer 2

2 supporting studies - fairburn and harrison- MZ 55% concordant
DZ 5% concordant

rippman et al 106 mz 46.2% concordant DZ 7.1% concordant

demonstrate significant difference between MZ and DZ twins MZ much higher - genetics play a key role in disorder

Question 3

A03.1 weakness

Answer 3

although MZ twins are not 100% concordant suggesting environmental factors do play a role in development of anorexia otherwise it would be 100%

Question 4

A03.1 weakness 2

Answer 4

twin studies sometimes carry validity issues as they overemphisise the role of genes as MZ twins- identical ,same gender are likely to have been treated the same way and like the same person than DZ we assume genetic reasons increase the concordance although it may be due to ENVIRONMENTAL SIMILARITY

Question 5

A01.2- family studies

Answer 5

if genes cause AN frewuancy of AN amoungst relatives should be higher then the general population

family studies look at first degree relatives of people with and without diagnosed AN in order to estabilish a heritability estimate - currently 70%

Question 6

A03.2 strength

Answer 6

WOODSIDE ET AL found that first degree relatives e.g. siblings/ parents are more likely to share having AN than 3rd degree relatives e.g. cousins auties uncles grandparents as fiest degree relatives share more genes then third

Question 7

A03.2 weakness

Answer 7

although first degree relatives often tend to live in the same household therefore the same environment meaning it could be due to envoronmental facotrs that cause AN

such as operant conditioning that suggests anorexia develops due to positive reinforcment such as gaining attention and compliemts for loosing weight- positive reinforcment and negative reinforcment - removal of megative comments for loosing weight

WADE et al found that when studying AN ppts childhood often consisted of family members making constant comments about their weight

thereofre it could be due to the enironment that e.g. siblings have been brought up in that causes AN not their genes

Question 8

A01.3

Answer 8

DAT1 - linked to the function of dopamine on the reward system
if gene is mutated dopamine activity is distrupted
resulting in a lack of motivation and satifaction others would get from eating

EPHQ2- gene produces an enzyme that helps regulate cholesteral metabolism which is connected to seritonin which is linked to anxiety and depression
gene influencees part of the brain involved with hunger and eating hypthalamus and fear response amygdala
problems with gene expression fear and low mood around doos due to impact on hunger regulation and fear response

ITPR3 codes for protein involved in taste of food such as bitter and sweet if gene is faulty those with AN mean unable taste removes motivation to eat

Question 9

A03.3 strength

Answer 9

scott van zeeland et al conducted a study using AN 60 females matched on age and ethnicity with 80 controls, DNA samples were taken.

found that no single genetic variance associated with AN but a combination of variant showed a significant genetic difference in ITPR3 gene and EPHQ2 gene

Question 10

A03.3 weakness

Answer 10

reductionist only considers biological factors and ignores contribution of the environment such as the rise of social media displaying idea body types limited exmplanation

Question 11

A03.3 strength/ application

Answer 11

if AN caused by bio factors such as genes, drug treatments can target this such as SSRI’s and antipsychotics help treat comorbid factors such as anxirty and depression leading to increased cooperation with other therapies,patient more willing to eat and gain weight

Question 12

conclusion

Answer 12

diathesis stress model best accounts for the influence of genes and the environment, AN is a biological predisposition but the effects are triggered by the environment
idiographic approach is needed