Evaluation of Dopamine and SZ Flashcards
+ Randup and Mankvad - rats
Randup and Mankvad raised dopamine levels of rats by injecting them with amphetamine. The rats showed positive symptoms of SZ - shows cause and effects between dopamine and SZ validating the theory
+ L-dopa
The drug L-dopa increases dopamine levels, and can produce many of the symptoms of SZ - suggests relationship between increased dopamine and SZ, validating the dopamine hypothesis
+ Blocking D2 receptors
Blocking D2 receptors in the mesolimbic pathway has been shown to reduce the positive symptoms of SZ - supports D2 pathways theory in suggesting dopamine in mesolimbic pathways increases SZ symptoms
+ Nicotine
Nicotine releases dopamine in the mesocortical pathway, alleviating negative symptoms. Smoking is particularly high among schizophrenics, and may be a method of self-medicating - supports D2 pathways theory, suggesting that negative symptoms are caused by low dopamine in mesocortical pathway, validating theory
- Glutamate
Another neurotransmitter, glutamate, is also thought to cause psychotic symptoms if production is blocked - suggests dopamine hypothesis ignores other biological factors that lead to SZ, making it reductionist and overly simplistic
- PET scans
PET scans show that blocking dopamine receptors does not always reduce symptoms - suggests that there must be other causes of SZ and that relying on dopamine alone is reductionist
- Social and environmental factors
Social and environmental factors can be involved. Stressful life events can trigger the production of excess dopamine - suggests theory is reductionist, and that it is hard to establish cause and effect, as increased dopamine may be the result of SZ
- Individual differences
It seems that some individuals are more susceptible to changes in dopamine levels in their brain than others. Some people are more prone to suffering from SZ than others - suggests theory ignores individual differences
