schizophrenia: neurotransmitters

Question 1

dopamine hypothesis

Answer 1

amphetamine use increased dopamine levels leading to hallucinations and delusions (positive symptoms), Lieberman et al amphetamine use show 75% of patients with schizophrenia

more D2 receptors= increased dopamine (Seeman 2013)

Randrup and Munkvard (1966) raised dopmaine levels in rats by injecting them with amphetamine making them more aggressive

Question 2

what is dopamine used for

Answer 2

pleasure and reward

Question 3

parkinsons and dopamine

Answer 3

too much

Question 4

revised dopamine hypothesis

Answer 4

positive symptoms= increased dopamine in mesolimbic pathway

negative symptoms= decreased dopamine in mesocortical pathway= lead to depression and lack of motivation

proven by PET scans and animal studies

lack of D2 receptors in one area can lead to more being created in another area (e.g. enlarged ventricles)

Question 5

glutamate

Answer 5

low glutamate in cerebal cortex= negative symptoms

high glutamate in basal ganglia= positive symptoms

Question 6

serotonin

Answer 6

high serotonin= negative symptoms

low serotonin= positive symptoms

Question 7

antagonist

Answer 7

bind to neurotransmitter but decreases the effect of neurotransmitter

Question 8

agonist

Answer 8

bind to synaptic receptors and increase the effect of the neurotransmitter

Question 9

Evidence

Answer 9

Falkai et al 1988

studied autopsies and found that people with schizophrenia have a larger than usual number of dopamine receptors

Question 10

Application

Answer 10

lead to an increased drug therapy e.g. anti-psychotics

Question 11

Comparison

Answer 11

Noll (2009) identified that in some cases, hallucinations and delusions occur in spite of normal dopamine levels in which case blocking the receptors has little or no effect on symptoms

Question 12

How good is the research

Answer 12

animal studies are used, reducing validity as humans and animals don’t have comparable brains such as pre-frontal cortex