biological explaantion for anorexia Flashcards
what are the twin studies in anorexia
Holland et al did studied 45 pairs of twins and found a concordant rate of 56.5% for mx twins
5% for dz twins
what do the results shows
the higher concordance rate in the mz twins suggest mostly due to genetic factors and as the proprtion of shared genes increase so does the likelihood of developing anorexia
so anorexia has a biological basis
what did scott ifentify
The faulty epxh2 gene that is associated with anorexia
what does this gene control and what does this means for anorexics
Since the gene involved function is to produce enzyme which regulates cholesterol
Having different versions of the gene , affects the enzyme structure which in turn affects the regulation of cholesterol
so they have abnormal levels of cholesterol
what may dopamine play a role in research
kaye et ak found that overactivity in the dopamine receptors in the basal ganglia where dopamine plays a role in pain and pleasure
what does this over activity cause
Abnormal activity in the basal ganglia alters the way we interpret rewards
This explains why some people with anorexia they find it difficult to feel pleasure by eating food
Further contributing to starvation
how does serotonin play a role in anorexia
Reserahc has found that people with anxiety caused by high levels of serotonin may often feel temporary calmness when they skip meals
how does this occur
serotonin synthesis requires adequate levels of tryptophan
And lack of nutrients prevent tryptophan from being transported to the brain
Lack of tryptophan distrupts serotonin synthesis
This leads to a lower level of serotonin which leads to temporary calmness
why does this then lead to anorexia
they want the continued feeling of calmness so continue to starve themselves resulting in inadequate levels of tryptophan
how is the biological explanaton considered to be a reductionist
Vagn and fouts carried out a longitudinal study which found adolescent girls whose an symptoms severity increase over a 16 month period also reported an increase in reading fahion mag
what does this shows
This demonstrates that anorexia may be causeed from the enviroment
Young people see those in magazines as role models and they may starve themselves to make themselves appear like the role models
The role models are glomourised and praised for their body shape
Through vicarious reinforcement young people are more likely to imitate their weight loss strategies in order to lose weight to get the same kind of attention
One weakness is that the biological explanation relies heavily on twin studies
the high concordance rate is believed to be due to the increase of shared genes from 50%-100%
what assumptions do twin studies make and why is this a problem
Twin studies amke equal enviromental assumption that the siblings in dz twins are treated the same as siblings in mz twims
But this overlooks the fact that mz twins look identical so they are more likely to be treated identically
what does this mean
Therefore the higher concordance rate may be due to the similair enviroment and treatments rather than genetics
Thus decreasing the valiity of the conclusion
There is research support for dopamine
revious research has shown that high levels of dopamine can lead to an increase in eye blink rate
Aditiionaly barbato found that an increase in eye blink rate in people with anorexia compared to control group , blink rate was higher in the older anorexics
