Biological Explantation For Schizophrenia: The Function Of Neurotransmitters

Question 1

Randrup and Munkwad (1966)

Answer 1

Raised dopamine levels in brain of rats by using amphetamine drug. The rats’ behaviour changed and was very similar to psychotic behavior in humans while having schizophrenia . They became more stereotyped, aggressive and isolated. → however, only a small proportion of people who regularly use these drugs suffer from psychotic symptoms, which suggests that there is something different about how some people’s brains react to dopamine. → supported by post-mortem examinations on the brains of schizophrenics ( 0wen et all ) It showed that schizophrenics have a higher density of dopamine receptors in certain parts of the brain (cerebral cortex) than do patients not suffering from schizophrenia, suggesting that they are more sensitive to the action of dopamine than people who have not had schizophrenia.

Question 2

Seeman(2013)

Answer 2

People diagnosed with schizophrenia may have a higher number of D2 high receptors - these receptors love a higher connection to dopamine, which means they are more likely to bind to he neurotransmitter

Question 3

Lieberman Et al

Answer 3

71% of patients with schizophrenia show new symptoms or an increase in psychosis after using amphetamines which increase dopamine

Question 4

Carlsson et Al

Answer 4

Found that schizophrenics which given amphetamines have a greater release of dopamine than those without schizophrenia, suggesting hypersensitivity to dopamine amongst those with the disorder → despite this, the theory is based upon animal studies e.g. Randrup and Munkwad, which lack generalisability to humans, as humans have far more complex biology and cognition.

Question 5

Parkinson disease

Answer 5

Those suffering with Parkinson disease have low levels of dopamine, and when given L-dopa (a drug to increase dopamine levels) patients can suffer symptoms of schizophrenia e g. Hallucinations and delusions

Question 6

However → Alpert and Iried Hoff

Answer 6

Found that not all patients with schizophrenia respond to drugs that reduce dopamine

Question 7

Reductionist

Answer 7

The dopamine hypothesis is reductionist as it fails to account for the role of the environment. It may be that environments stressors trigger the disorder.

Question 8

Brown and Birley

Answer 8

Found that 50% of those with schizophrenia had a major life event in the three weeks prior to velopse, suggesting the role of an environment trigger of schizophrenia

Question 9

Useful for society

Answer 9

It has led to the development of drug therapy for schizophrenia - antipsychotic drugs that reduce dopamine are effective in treating schizophrenia