L4 The Dopamine Hypothesis

Question 1

What are Neural Correlates?

Answer 1

• Measurements of the structure or function of the brain that have a relationship with SZ, especially different regions of the brain
• How different neurotransmitters, e.g dopamine, in different parts of the brain can also play a part in SZ

Question 2

• What is the Dopamine Hypothesis?

Answer 2

• Claims that an excess of the neurotransmitter dopamine in certain regions of the brain is associated with positive symptoms of SZ
• Messages of neurons that transmit dopamine fire too easily, leading to hallucinations and delusions
• Schizophrenics have a high number of D2 receptors on receiving neurons, leading to more dopamine binding and more neurons firing

Question 3

What is Hyperdopaminergia in the subcortex?

Answer 3

• States that there are high levels of activity of dopamine in an area of the brain known as the subcortex

Question 4

What is Hypodopaminergia in the cortex?

Answer 4

• Recent versions of the dopamine hypothesis have focused on lower levels of dopamine in the cortex
• Role of low levels of dopamine in the prefrontal cortex for negative symptoms of SZ

Question 5

Strengths of the Dopamine Hypothesis? (3)

Answer 5

L-dopa
Use of Antipsychotic drugs
Reliable and Valid information

Question 6

L-dopa (+)

Answer 6

• When SZ patients were given the drug L-dopa their condition got worse and were intensified
• Shows the strong link between more dopamine and increased SZ symptoms

Question 7

Use of Antipsychotic drugs (+)

Answer 7

• Works to reduce the levels of dopamine in the brain, dopamine antagonists
• Supports the idea that dopamine levels in SZ patients are high and can be reduced through drugs

Question 8

Reliable and Valid information (+)

Answer 8

• Scientific evidence for the dopamine hypothesis is a cause of SZ
• Most of the research is from brain scans, PET and fMRI’s which is highly valid and reliable

Question 9

Weaknesses of the Dopamine Hypothesis? (3)

Answer 9

Cause and Effect is Wank
Biological Reductionism
Dopamine is present in many illnesses, not just SZ

Question 10

Cause and effect is wank (-)

Answer 10

• Large number of neural correlates of SZ are involved with its development
• We can question however whether dopamine really is the cause of SZ, or merely a correlation found within patients
• Could it be that once a person has SZ, they then have high dopamine and not the other way?

Question 11

Biological Reductionism (-)

Answer 11

• Reduces the complicated phenomenon of the causes of SZ and reduces it down to dopamine alone
• There are much more factors, e.g family dysfunction

Question 12

Dopamine is present in many illnesses, not just SZ (-)

Answer 12

• The role of dopamine is associated with things like bipolar too
• This shows how dopamine has a complex role in the brain and might be associated with many psychological illnesses and not SZ alone