The Neurotransmitter Explanation for Sz

Question 1

What does dopamine cause neurons to do?

Answer 1

Causes neurons to fire in the brain which sends messages around the CNS

Question 2

What do brain scans suggest about excess dopamine receptors?

Answer 2

Suggest that the presence of excess dopamine receptors at the synapses in the brain contribute to Sz

Question 3

How does dopamine affect activity in the brain?

Answer 3

Lots of dopamine receptors increases activity in the brain

More firing of neurons and more messages sent around the brain

Question 4

What is not enough dopamine linked to?

Answer 4

Not enough dopamine receptors is linked to symptoms of Sz

Question 5

Which areas of the brain are linked to positive symptoms of Sz?

Answer 5

Mesolimbic pathway

Nucleus Accumbens (NA)

Ventral Tegmental Area (VTA)

Question 6

What does too much activity in the dopamine receptors lead to?

Answer 6

Too much activity leads to hyperactivity or hyperdopaminergia

Question 7

What does the mesocortial pathway connect the cortex with?

Answer 7

Connects the cortex with the VTA

Question 8

What does too few dopamine in the mesocortical pathway lead to?

Answer 8

Too few dopamine receptors in this pathway leads to less firing and negative symptoms of Sz

Question 9

What is the supporting evidence/strengths of the neurotransmitter explanation for Sz?

Answer 9

Levodopa

Seidman (1990)

Psychological knowledge in society

Question 10

What is the refuting evidence/weaknesses of the neurotransmitter explanation for Sz?

Answer 10

Carlsson et al (1999)

Reductionist

Limited generalisability

Question 11

Why is Levodopa supporting evidence for the neurotransmitter explanation for Sz?

Answer 11

Levodopa is given to patients with Parkinson’s disease to increase their dopamine levels

If the dosage is too high or with prolonged use they produce symptoms similar to Sz

Supports link between increased levels of dopamine and Sz

Question 12

Why is Seidman (1990) supporting evidence for the neurotransmitter explanation for Sz?

Answer 12

Found evidence from post-mortem examinations of people with Sz and identified a larger than average number of dopamine receptors in their brains

Supports the role of neurotransmitters as an explanation for Sz

Question 13

Why is psychological knowledge in society a strength of the neurotransmitter explanation for Sz?

Answer 13

Reducing explanation down to hyperdopaminergia led to development of a group of drugs called Phenothiazines in the 1950s

Work by blocking dopamine receptors to prevent the excess dopamine which reduced positive symptoms of Sz

Supports idea that excess dopamine is a cause of Sz

Question 14

Why is Carlsson et al (1999) refuting evidence for the neurotransmitter explanation for Sz?

Answer 14

Disputes the simplicity of this explanation claiming that glutamate (if production is blocked) also has a role in the onset of Sz, not simply dopamine alone

Explanation may be criticised for being reductionist by isolating only one neurotransmitter as an explanation for Sz

Question 15

Why is reductionism a weakness of the neurotransmitter explanation for Sz?

Answer 15

Theory simplifies the complexity of human behaviour down to a single neurotransmitter

Ignores other factors which may affect behaviour e.g. role of glutamate, genetics, environmental factors such as stress which trigger Sz

Explanation may be criticised for being biologically reductionist

Question 16

Why is limited generalisability a weakness of the neurotransmitter explanation for Sz?

Answer 16

Research to investigate dopamine pathways often carried out on animals by lesioning their brains in highly controlled lab experiments which cannot mirror complexity of human interactions with their environment