Sz: Neurotransmitters

Question 1

A01

Answer 1

Chemical imbalence in NT
Causes excess signalling
High level dopamine linked to:
hallucinations and paranoia 
Sensative/too many receptors (D2)
Illicit drugs- amphetamines cause increase in dopmine at D2- cause sz symptoms

Question 2

Update

Answer 2

Davis (1991) initially thought just high dopamine

Howes and kapur (2009) suggests actual D levels rather than D2- focused on psychosis proneness (explains + - symptoms)

Question 3

+AO3

Answer 3

Since anti-psychotic drugs lower dopamine adds credibility
Amphetamines are DA agonists (raise dopamine) and cause sz side effects
L-dopa treats parkinsons by raising DA (side effect is hallucinations)
Scientific and objective (empirically measures chemicals)

Question 4

+carlsson

Answer 4

Did a review study and identified that evidence from many studies which demonstrated high levels of dopamine are related to sz

Question 5

+ seeman (2013)

Answer 5

They have higher no. of D2 receptors

Question 6

+ Davis (1974)

Answer 6

Injected sz with methylphenidate and found a marked increase in symptoms

Question 7

+ Randrup and maunkvad (1966)

Answer 7

Raised dopamine levels in brains of rats when injected by amphetamines.
Rats changed behaviour (aggressive and isolated)
Showing change in DA levels resulted in psychotic-type behaviours
Consistent with sz

Question 8

• AO3

Answer 8

Cause and effect issues
Difficult to test chemicals in the brain/ synapse
Using urine or blood samples lowers validity (unclear where they came from)
Amphetamines only cause + symptoms (means its not not just dopamine- reductionist)
Drugs won’t work for everyone (there are other issues)
Reductionist no cognitive
Drugs don’t work right away (other factors)
Glutamate tied to sz

Question 9

-carlsson

Answer 9

It’s not just dopamine but other NT too

Question 10

• kqon et all (1999)

Answer 10

25% reduction of grey matter in frontal & temporal lope- so may be other brain difference

Question 11

Depatie and lal (2001)

Answer 11

Apomorphine is a drug which increases effects of dopamine however this drug does not lead to sz symptoms when given to normal controls

Question 12

Javitt & zukin (1991)

Answer 12

Showed that the recreational drug PCP (blocks Glutamate receptors) creates sz symptoms

Using animal experiments showed drugs that increase Glutamate activity (reverse PCP induced psychosis)