biological explanation of schizophrenia-dopamine hypothesis Flashcards
what does the dopamine hypothesis suggest?
dopamine caused by:
- excess amounts of dopamine
- sensitive dopamine receptors
- too many dopamine receptors
what receptor, in particular, does the explanation suggest is impaired?
D2 receptors
what symptoms does this explanation explain? (2)
- -hallucinations
- paranoia
what drug causes excess levels of dopamine consequently in schizophrenic symptoms e.g. hallucinations
amphetamines
what causes negative symptoms?
hypodopimanergia (decreased dopamine) in mesocortical pathway
what causes positive symptoms?
hyperdopimanergia (increased dopamine) in the mesolimbic pathway
what behaviours is dopamine associated with? (5)
- attention
- exploratory
- outgoing
- pleasure-seeking
- locomotor system
what does glutamate do?
- low levels=development of psychotic symptoms
- hypoglutamatergia=doamine levels risee
SUPPORTING EVIDENCE (2)
- Falkai et al-autopsies show people with sz have larger receptors (D2 receptors)
- Van Rossum-significant link between overstimulation of dopamine receptors and sz
CONFLICTING EVIDENCE (2)
- Carlsson et al-animal study showed that NMDA antagonists uced levels of glutamate but didn’t always increase dopamine
- PET scans showed drugs that blocked dopamine didn’t reduce symptoms in 10yr sz patient
OTHER EXPLANATIONS (2)
- envvironmental factors e.g. poverty, unemployment
- non-biological explanation (cognitive)-faulty info processing-explains neg symptoms- can’t filter out cog noises in environment
USEFULNESS (3)
+help create drugs to lower dopamine levels
+preventative strategies- can test blood/brain scans to monitor the progression of sz
- socially controlling- used to change and manipulate behaviours
TESTABILITY (3)
scientifically tested
- can’t establish cause and effect
- animal studies
