Contemporary study: Carlson et al (2000)

Question 1

Aim

Answer 1

Conduct evidence for and against the dopamine hypothesis of schizophrenia

Also wanted to explore the glutamate hypothesis

Question 2

IV, DV and sample

Answer 2

None of this existed as he conducted a meta analysis of 33 studies

Question 3

Procedure

Answer 3

Meta analysis of multiple studies looking into the role of neurotransmitters in schizophrenia.

• Alot of the studies involved PET scans

Question 4

Results: The dopamine hypothesis revisited

Answer 4

Evidence for dopamine hypothesis, schizophrenic patients shown to have more dopamine activity than healthy control group.

Question 5

What part of the brain were these high levels of schizophrenia spotted

Answer 5

Basal Ganglia

Question 6

Results: beyond dopamine

Answer 6

Carlsson also looked at Glutamate as a possible explanation.

Question 7

Why did Carlsson look at Glutamate

Answer 7

The drug ‘angel dust’ induced schizophrenic like symptoms and its a powerful antagonist for glutamate receptors.

Question 8

Results: Glutamate-dopamine interaction at the post synaptic level

Answer 8

Low levels of glutamate link with both positive and negative schizophrenic symptoms

Question 9

What was the possible cause for positive symptoms

Answer 9

low levels of glutamate in subcortical basal ganglia

Question 10

What was the possible cause for negative symptoms

Answer 10

Low levels of glutamate in cerebral cortex

Question 11

Results: Glutamatergic control of dopamine release

Answer 11

Glutamate molecules may release GABA. This causes dopamine activity to decrease. Low levels of glutamate thought to increase dopamine activity.

Question 12

Results: Comparing 2 experimental schizophrenia models (what were the 2 models)

Answer 12

1. Hypodopaminergia
2. Hypoglutamatergia

Question 13

What is hypodopaminergia

Answer 13

low levels of dopamine

Question 14

What is hypoglutamatergia

Answer 14

low levels of glutamate

Question 15

What did Carlsson find when comparing these 2 models

Answer 15

These 2 models can explain why some people respond better to some antipsychotics than others.

• Some people who dont respond typical antipsychotic
  drugs that reduce dopamine might have a more
  glutamatergic condition instead

Question 16

Conclusion: what did Carlsson conclude

Answer 16

There are probably different groupd of schizophrenia patients whos symtoms have different explanations. There fore more research needs to be done on other neurotransmitters

Question 17

EVALUATION

Answer 17

Evaluation

Question 18

What is a strength of the generalisability

Answer 18

The studies that were reviewed are very representative selection of what was going on at the time of the field

Question 19

Why would the studies be very representative

Answer 19

Carlsson was a top researcher into dopamine aswell as schizophrenia, he even won a nobel prize.

Question 20

What is a weakness of the generalisability

Answer 20

Study is time locked

Question 21

Why is this study time locked

Answer 21

it was conducted in 2000, so it cannot be representative of what we know now.

Question 22

What is a strength of the reliability

Answer 22

All the studies carlsson looked at are easy to replicate

Question 23

Why are the studies carlsson looked at easy to replicate

Answer 23

They were lab experimentas that used modern brain imaging techniques like PET scans

Question 24

What is a strength of the application of Carlssons analysis

Answer 24

It led to the improvements of drug treatments based on new understanding of neurotransmitter pathways

Question 25

What are some improvents of drug treatment it caused

Answer 25

new dopaminergic drugs now are more effective with fewer side effects
- new atypical drugs now effect more neurotransmitters like Glutamate and serotonin

Question 26

What is a weakness of the validity of the meta analysis

Answer 26

The results were gathered through secondary data and most of the studies he looked at were lab experiments

Question 27

How does secondary data affect the validity

Answer 27

You wouldn’t know if the participants were acting normally in a realistic setting. In this case most likely not because most the studies were lab experiments.