Scz: dopamine hypothesis

Question 1

What does excess dopamine in the mesolimbic pathway do?

Answer 1

Cause positive symptoms such as hallucinations and delusions

Question 2

What does excess dopamine in the mesocortical pathway do?

Answer 2

Cause negative symptoms ie social withdrawal

Question 3

What is the dopamine hypothesis?

Answer 3

Dopamine neurone play a key role in guiding attention so disturbances in this process may lead to problems with attention and thought that people with scz have

Question 4

What can be said about the validity of the dopamine hypothesis

Answer 4

Falkai et al, Owens et al and seeman et all all found similar supporting evidence over a long period of time which increased temporal validity

Question 5

Is blocking dopamine always effective?

Answer 5

No, 90% of dopamine receptors were blocking in people who had scz for ten years and there was no reduced symptoms
HOWEVER
it was 90% effective in patients in early stages of scz

Question 6

What is dopamine activity associated with?

Answer 6

Exploratory, out-going, pleasure seeking behaviours.

Increased feelings of paranoia

Question 7

What is the glutamate hypothesis?

Answer 7

Glutamate is another neurotransmitter associated with schizophrenia.
Glutamate antagonists inhibit the release of dopamine.

Question 8

What’s an antagonist?

Answer 8

Blocks a receptor and deactivates it (lowering the level of the chemical)

Question 9

What’s an agonist?

Answer 9

Activated the synapse, raising the level of the chemical

Question 10

How do amphetamines support the dopamine hypothesis?

Answer 10

They’re a DA agonist, they can lead to amphetamine psychosis with symptoms similar to scz e.g. cocaine can cause hallucinations

Question 11

How do amphetamines conflict the hypothesis?

Answer 11

When we give people LSD or cocaine we see hallucinations, delusions etc but no negative symptoms suggesting DA levels don’t cause all symptoms of scz