Biological Explanations Of Schizophrenia

Question 1

Dopamine explanation of schizophrenia

Answer 1

Initial dopamine hypothesis - the brains of schizophrenics produce more dopamine than a normal brain (hyper dopaminergia) for example an excess of dopamine receptors in Broca’s area which is responsible for speech production so may be linked to speech poverty
Research shows that autopsies have found that those with schizophrenia have a larger number of d2

Further discovery showed several subtypes of dopamine receptor sites (d1-5) which is spread in the cortical (cerebral coretex) and subcortical (lambic system)

Reversed dopamine hypothesis:
-Mesolimbic pathway (positive systems)
Carries signals from VTA-NA
Too much dopamine causes overstimulation resulting in positive symptoms
Antipsychotics reduce dopaminergic neurotransmission which reduces dopamine so therefore positive symptoms
-mesocortical pathway (negative symptoms)
Carries signals from VTA-NA then to the frontal lobe
This nerve pathway is vital for emotion and motivation
Little dopamine (hypofunction) is evident in D1 receptors of the frontal lobe of many individuals of negative symptoms

Question 2

Evaluation of dopamine hypothesis- supporting research

Answer 2

S- strength as there is research to support
E-research into post mortams show an increased number of dopamine receptors in those with schizophrenia
E-this suggests that dopamine implicates schizophrenia
C-however the useful of the research needs to be questioned as studies are on dead brains so cannot show dopamine activity during a schizophrenic episode
W-though supporting research shows a link between increased dopamine and schizophrenia more reliable research needs to be conducted

Question 3

Evaluation of dopamine hypothesis - development of drug therapy

Answer 3

S- helped to develop drugs for sz treatment
E-first generation of antipsychotics were developed as dopamine antagonist (blocks D2) to target the overproduction of dopamine - these were found to be effective against positive symptoms
E- 75% given the drug were found to be much improved
W-this is a strength as it reduces positive symptoms due to a relevant theory being explored

Question 4

Evaluation of dopamine hypothesis - reductionism

Answer 4

S- weakness
E-this is biologically reductionist and is too simple to suggest schizophrenia is caused by dopamine - one singular neurotransmitter
E-could be other factors implementing both biological or environment e.g upbringing to trauma
C-however allows us to study in depth and scientifically how dopamine is linked and its role ion schizophrenia
W-despite being arguied it is too simplistic, reductionism can be a strength as it allows us to understand a potential cause of SZ from a scientific viewpoint

Question 5

Evaluation of dopamine hypothesis - cause and effect

Answer 5

S- hard to establish cause and effect
E-could be said that schizophrenia causes a dopamine imbalance
E-is it a symptom of schizophrenia not a cause? - as investigative techniques become less invasive we will be able to establish which comes first through research
W-we cannot say explicitly that dopamine is the only cause

Question 6

Biological explanation - genetics ( 2nd option)

Answer 6

This explanation believes that schizophrenia is inherited through genes passed down through families:
Family studies:
Research by gottesman investigated the inheritability of SZ
He found indentical MZ twins have a 48% chance
Non identical DZ twins = 17%
Parents = 6%
Siblings = 9%
This suggests that the more biological makeup you share with someone the more likely your are to develop schizophrenia

Question 7

Evaluation genetics (2nd option)

Answer 7

S- criticisms of supporting research
E-research suggests a concordance rate for sz in my twins is 48%
E-this does suggest some biological basis
C-however results are not 100% so genetics can not be used alone
W-incomplete explanation