Bio explanation - sz Flashcards
(13 cards)
What is the dopamine hypothesis?
those with sz have too many dopamine receptor sites in the brain - leads to too much dopamine being used which causes sz symptoms
- also have too many D2 receptor sites - type of dopamine receptors site which is most likely to pick up dopamine than any other dopamine receptor site
What is the function of dopamine?
mood regulation, motivation, activates reward pathway
Increase in different pathways?
mesolimbic - positive symptoms
mesocortical - negative symptoms
3 other info (DAH):
- some take recreational drugs to increase dopamine for the purpose of experiencing hallucinations
- cause for excess DA and D2 receptors is not yet known
- antipsychotics reduce DA levels in brain
Strengths (DAH)
- Lindstroem - gave L-DOPA 10 ppts with and 10 ppts without sz - PET scans showed DA was taken up quicker in those with sz - evidence of excess receptor sites
- Randrup + Munkvard - injected amphetamines into rats - DA levels increased and animals behaved psychotically
What are amphetamines?
recreational drugs - speed up workings of the brain
Weakness (DAH)
- Depatie and Lal - individuals given a drug to increase DA production, so symptoms not created - DA levels not only cause for sz
What is the genetic explanation?
likelihood of sz increases with genetic similarity
What is the likelihood of getting sz with a second degree relative with sz?
2-6%
What is the likelihood of getting sz in MZ twins?
48%
What is the COMT gene?
instructs the creation of an enzyme which breaks down NT such as dopamine in the pre frontal cortex - without this, DA levels would not be regulated, causing sz symptoms
Strength (GE)
Gottesman - concordance rate for MZ twins is 48% and for DZ is 17% - genetic component supported
- not direct cause or concordance would be 100%
Weakness (GE)
sz can occur without having a family member with it - approx 80% do not have family history of sz - usefulness questioned
