ANXIETY explanations biological

Question 1

biological explanation

Answer 1

genetic inheritance
de novo mutations

Question 2

genetic inheritance

Answer 2

before human genome project 2003 relied on family twin and adoption studies to research nature nurutre in anxeity disorders

blood phobia may be more heritable than other specific phobias
had parent or sibling w it

Question 3

de novo mutations

Answer 3

vulnerability - genetic
differences between people w and without may not be genetic inheritance
instead bc of new or de novo genetic mutations
can affect mental health but are not present in all or even any of the biological parents’ cells

Question 4

de novo mutation gratacos et al. 2001

Answer 4

sample of spanish ps
de novo mutation thought to be linked w agoraphobia and specific phobias
90% of people w fear related disorders had a duplication of a stretch of DNA on chromosome 15 called DUP25
with 7% of control group of people without fear related disorders

link between DUP25 and anxiety is believed to be assocuated with the duplication of the NTRK3 gene

prev reserach has linked this gene to emotional and behavioural arousal in response to external stimuli

over espression = increase vulnerability

Question 5

NTRK3 gene

Answer 5

neutrophins are proteins essential for healthy function and development of neurons

NTRK3 provides instructions for development of NT-3 neurotrophin

many of these in brain structure called locus coeruleus in brain stem

this brain structure has been linked to arousal vigilance attention
over expression of the NTRK gene in this brain structure may be linked to high levels of norad and a neurotransmitter linked with stress and anxiety (armengol et al 2002)

Question 6

genetic strength evidence validity

Answer 6

supported by twin studies
distel et al 2008
concordance of 39% for MZ twins
9% for DZ twins
one twin was diagnosed w disorder
both twins in each pair similar environmental circumstances
diff in concordance rates can only be explained by the diff in amount of shared DNA between MZ and DZ twin pairs (ie 100% w 50%)

Question 7

more evidence dierssen et al 2000

Answer 7

transgenic mice
dierssen et al 2006
mice over expressed NTRK3 gene showed increased anxiety like behaviour and panic responses
when encountering threatening stimuli and situations in a test called Mouse defense test battery

mice also had higher desnity of neurons that communicate via norad in locus coeruleus
this suggests that DUP25 may increase vulnerability to anxiety disorders and fear related disorders in humans

Question 8

determinism vs free will genetic

Answer 8

WEAKNESS too deterministic
eg suggests over or under expression of genes determines how we think feel behave

ignores role of free will

some people may be more vulnerable to anxiety due to genes but choose to use techniques such as mindfulness and yoga to control their anxiety

research demonstrates such behaviours can be effective in altering brain chemistry
so FREE WILL important role

Question 9

nature vs nurture genetic

Answer 9

WEAKNESS ignores nurture

epigenetic research suggests environmental factors can affect gene expression
de novo mutations
genetic explanational alone cannot explain why 60% of people w DUP25 do not develop anxiety do not develop anxiety disorders

important bc demos that genetic over simplified reductionist

imporyant environmental factors may protect genetically predisposed individuals from developing symptoms