Biological Explanations to AN

Question 1

What are the 2 types of biological explanations for AN?

Answer 1

1) Neural

2) Evolutionary

Question 2

What do we mean by neural explanations?

Answer 2

Changes in the neural system

Question 3

What do we mean by evolutionary explanations?

Answer 3

Adaptive functions of AN

Question 4

How many neural explanations are there for AN?

Answer 4

3

Question 5

Name the 3 neural explanations of AN

Answer 5

1) Serotonin
2) Dopamine
3) Neurodevelopment - pregnancy and birth complications

Question 6

What is the main study for serotonin in AN?

Answer 6

Bailer (07)

Question 7

Outline Bailer (07)

Answer 7

Compared serotonin activity in women recovering from restricting-type AN (restricted food intake), and binge-eating/purging type (periods of restricted eating and binge-eating/purging) with healthy controls - found significantly higher serotonin activity in women recovering from binge-eating/purging type - in addition, found highest levels of serotonin activity in women who showed most anxiety, suggesting that persistent disruption of serotonin levels may lead to increased anxiety which may trigger AN

Question 8

What is the main study for dopamine in AN?

Answer 8

Kaye (05)

Question 9

Outline Kaye (05)

Answer 9

Used PET scans to compare dopamine activity in brains of 10 women recovering from AN and 12 healthy controls - in AN women, found over activity in dopamine receptors in part of brain known as basal ganglia where dopamine plays part in the interpretation of harm and pleasure - increased dopamine activity in this area appears to alter way people interpret rewards - individuals with AN find it difficult to associate good feelings with things most people find pleasurable like food

Question 10

What are the 2 main studies for pregnancy and birth complications for AN?

Answer 10

1) Lindberg & Hiern (03)

2) Bulik (05)

Question 11

Outline Bulik (05)

Answer 11

Suggest mothers with AN expose their offspring to a ‘double disadvantage’ - transmission of genetic vulnerability to AN and inadequate nutrition during pregnancy

Question 12

Outline Lindberg & Hiern (03)

Answer 12

Found significant association between premature birth and development of AN

Question 13

Outline pregnancy and birth complications for the biological explanations of AN

Answer 13

Birth complications may lead to brain damage caused by hypoxia (lack of oxygen), impairing neurodevelopment of the child - nutritional factors may be implicated if mothers have an eating disorder

Question 14

What are the 2 evolutionary explanations of AN?

Answer 14

1) Reproductive Suppression Hypothesis

2) The ‘adapted to flee’ hypothesis

Question 15

Outline Reproductive Suppression Hypothesis for AN

Answer 15

Surbey (87) suggest adolescent girls’ desire to control their weight represents an evolutionary adaptation in which ancestral girls delayed the onset of sexual maturation in response to cues about the probability of poor reproductive success - ability to delay reproduction is adaptive because enables female avoid giving birth at time when conditions are not conductive to her offspring’s survival - argues AN is disordered variant of adaptive ability of females to alter timing or reproduction at a time when they feel unable to cope with biological, emotional and social responsibilities of womanhood

Question 16

What is the Reproductive Suppression Hypothesis for AN based on?

Answer 16

The observation that in a number of species, puberty delayed or reproduction suppressed in females when subjected to stress or are in poor physical condition

Question 17

Who came up with the ‘adapted to flee’ hypothesis ?

Answer 17

Guisinger (03)

Question 18

Outline the ‘adapted to flee’ hypothesis for AN

Answer 18

Proposes typical AN symptoms of food restriction, hyperactivity and denial of starvation reflect operation of adaptive mechanism that once caused migration in response to local famine conditions - normally, when person begins to lose weight, physiological mechanism conserve energy and increase desire for food - these adaptations facilitate survival in hard times - however, among ancestral nomedic foragers, when extreme weight loss due to severe depletion of local food resources, this adaptation must be turned off so that individuals can increase chances of survival by migrating to more favourable environment - food restriction is common feature of many species when feeding competes with other activities such as migration or breeding

Question 19

Evaluate serotonin for AN

Answer 19

SSRIs (alter levels of available brain serotonin) ineffective when used with AN patients - Kaye (01) however found when used with recovering AN patients, effective in preventing relapse - malnutrition-related changes in serotonin may negate action of SSRIs which only become effective when weight returns to more normal level

Question 20

What are 2 evaluative studies on dopamine for AN?

Answer 20

1) Castro-Fornieles (06)

2) Wang (01)

Question 21

Outline Castro-Fornieles (06)

Answer 21

Found adolescent girls with AN had higher levels of homovanillic acid (waste product of dopamine) than a control group - improvement in weight levels associated with normalisation of homovanillic levels

Question 22

Outline Wang (01)

Answer 22

Found lower than normal levels of dopamine receptors in brains of obese individuals

Question 23

Evaluate dopamine for AN

Answer 23

Levels of dopamine appear to be related to body weight, but not clear as to whether this is a cause or consequence

Question 24

What is the key study for the evaluation of neurodevelopment for AN?

Answer 24

Favaro (06)

Question 25

Outline Favaro (06)

Answer 25

Followed group of children from birth to adulthood - found perinatal (immediately before or after birth) complications significantly associated with risk of developing AN were placental infarction (obstructed blood supply in the placenta), early eating difficulties and low birth weight

Question 26

Evaluate the reproduction suppression hypothesis for AN

Answer 26

Supported by observation that menarche (onset of puberty) is delayed in prepubertal girls with AN - also amenorrhoea typical characteristic meaning reproduction is effectively suspended in anorexic females

Question 27

Evaluate the ‘adapted to flee’ hypothesis

Answer 27

There are treatment implications - Guisinger claims struggle for control between those with AN and those who want them to get better is typical characteristic of AN - awareness of this can help treatment and encourage parents to be more compassionate toward anorexic child

Question 28

Evaluate the problems associated with using evolutionary explanations for AN

Answer 28

Might question how symptoms of AN might be passed on by natural selection particularly as they decrease fertility and could even kill the individual

Question 29

Name 4 general positive evaluative points about biological explanations

Answer 29

1) Evidence to support the biological basis
2) Can lead to successful drug therapies as drugs which reduce serotonin can be effective
3) Linked to biological explanations so people realise they are dealing with dysfunctional biology (treatable) and not dysfunctional family - reduces guilt generated by view parents cause development of eating disordered in children
4) Explains why people with AN display abnormal eating patterns

Question 30

Name the 7 general negative points about biological explanations

Answer 30

1) Often small samples
2) No one biological mechanism has been found as the cause of the disorder
3) Cannot account for recent increase in AN
4) Cannot explain why there isn’t 100% concordance for AN in twins
5) Cannot explain massive sex differences in incidence
6) Do not explain psychological aspects: intense fear of fat, distorted body image, and also need psychological, social and cultural factors
7) Gender-bias - most studies concentrate on women but 25% of adults with eating disorders are men

Question 31

Outline the diathesis-stress model for AN

Answer 31

Possible some individuals born with biological predisposition to develop AN - inherit vulnerability or risk factor - the diathesis - key vulnerability of AN is obessionailty - this is then triggered by life stressors, like in the teenage years - biological mechanism may perpetuate the illness