The dopamine hypothesis (biological explanation)

Question 1

what does dopamine do?

Answer 1

• increases the rate of neurons firing during synaptic transmission
• involved in pleasure and motivation

Question 2

what was the original dopamine hypothesis?

Answer 2

hyperdopaminergia in the subcortex

Question 3

what did the original dopamine hypothesis focus on?

Answer 3

• the role of high levels of dopamine in the subcortex

- too much dopamine = positive symptoms

Question 4

describe the receptors involved in hyperdopaminergia

Answer 4

p’s with schz:

• have excess dopamine (D2) receptors
• this leads to more dopamine
• more neurons fire

Question 5

describe the location of hyperdopaminergia

Answer 5

• occurs in Broca’s area

- associated with poverty of speech / auditory hallucinations

Question 6

what is the newer dopamine hypothesis?

Answer 6

hypodopaminergia in the cortex

Question 7

what does the newer dopamine hypothesis focus on?

Answer 7

• abnormal dopamine systems in the cortex

- too little dopamine = negative symptoms

Question 8

describe the receptors involved in hypodopaminergia

Answer 8

Davis (1991):

• prefrontal cortex doesn’t have D2 receptors it has D1
• D2 can’t be the only receptor involved
• reduced dopamine in the front of brain = negative symptoms

Question 9

describe the location of hypodopaminergia

Answer 9

Goldman - Rakic (2004):

- low levels of dopamine in the prefrontal cortex

Question 10

what is the overall conclusion of the dopamine hypothesis?

Answer 10

both hypodopaminergia and hyperdopaminergia are responsible for schz

Question 11

what are the strengths of the dopamine hypothesis?

Answer 11

• 2 supporting research’s (both part of the same evaluation)

- practical applications

Question 12

what is the 2 supporting researchers of the dopamine hypothesis?

Answer 12

• Randrup and munkvad

- Patel

Question 13

what was Randrup and Munkvad’s supporting research of the dopamine hypothesis?

Answer 13

• created schz like behaviour in rats
• gave rats amphetamines to increase dopamine
• reversed effects using neuroleptic drugs to reduce dopamine
• low and high levels of dopamine cause schz

Question 14

what was Patel’s supporting research for the dopamine hypothesis?

Answer 14

• used PET scans
• found lower levels of dopamine in prefrontal cortex of schz p’s
• supports low levels of dopamine causes schz

Question 15

what are the practical applications of the dopamine hypothesis?

Answer 15

Leucht (2013):

• did meta analysis on 212 students
• analysed effectiveness of antipsychotic drugs compared to a placebo
• drugs were more effective at treating positive and negative symptoms
• shows dopamine is involved and we can develop medication

Question 16

what are the weaknesses of the dopamine hypothesis?

Answer 16

• reductionist
• ignores role of family
• methodology

Question 17

how is the dopamine hypothesis reductionist?

Answer 17

• complex disorder can’t be explained by just 1 neurotransmitter (NT)
• dopamine is not the NT involved
• serotonin and glutamate are also involved
• too simple to just look at dopamine
• need to consider other factors

Question 18

how does the dopamine hypothesis ignore the role of the family?

Answer 18

• cold / rejecting mum can cause a tense environment
• can be catalyst for schz symptoms
• genetics can’t be the sole reason for such a complex disorder
• e.g consider family dysfunction explanation

Question 19

how is methodology a weakness of the dopamine hypothesis?

Answer 19

• research is of p’s w/ schz
• dopamine may be affected by schz
• imbalance of dopamine may be a symptom not cause
• can’t conclude dopamine causes schz