Carson (2000) - Contemporary Study

Question 1

Background

Answer 1

Review dopamine hypothesis and role of glutamate in sz
Considers 2 main areas - hyperdopaminergia (high dopamine) and hypoglutamatergia (low glutamate)

Question 2

Aim

Answer 2

To investigate relationship between dopamine and glutamate
Review anti-psychotics that could be more effective

Question 3

Procedure

Answer 3

Literature review of 33 studies
Investigating neurochemical levels in sz patients
Studies into drugs known to induce psychosis (angel dust)
Variety of methods eg. brain scanning animal studies
LAURELLE - gave sz patients in acute episodes an amphetamine = induced release of dopamine
MILLER AND ABERCROMBIE - used rats to test NTs levels where competitive NMDA inhibited dopamine release

Question 4

Results

Answer 4

Sz patients have higher dopamine compared to controls especially in BASAL GANGLIA
PCP leads to psychosis and blocks glutamate receptors = glutamate deficiency has a role in psychosis
Clozapine effective treatment - especially in treatment resistant patients as it targets serotonin

Question 5

Conclusion

Answer 5

Subpopulations of sz that could be caused by other NTs not just dopamine
Further research needed in developing drugs that avoid negative side effects

Question 6

Generalisability

Answer 6

HIGH - Uses patients with positive/negative symptoms, acute episodes etc
LOW - Uses animal studies

Question 7

Reliability

Answer 7

HIGH - 33 studies all support each other

Question 8

Validity

Answer 8

LOW - Publication bias 14/33 studies were his own = low internal validity = know his studies will support his own hypothesis

Question 9

Application

Answer 9

YES - Improving drug treatments, found clozapine useful - improved conditions for 13% of resistant patients