Schizophrenia: Biological Explanations - THE DOPAMINE HYPOTHESIS

Question 1

What is dopamine?

Answer 1

a neurotransmitter made in the brajn

Question 2

What does dopamine play a role in?

Answer 2

plays a role in the “reward centre” of the brain

Question 3

What functions is dopamine involved in?

Answer 3

• memory
• movement
• motivation
• mood

Question 4

What assumption is the explanation of schizophrenia based on?

Answer 4

base on the biological assumption that neurotransmitters cause behaviour

Question 5

What will happen if there are abnormalities in the way neurotransmitters are produced?

Answer 5

then this will lead to abnormalities in functioning and behaviour

Question 6

What did research into from the 1950s on Parkinson’s Disease find?

Answer 6

• found that drugs that increased the levels of dopamine in the brain reduced Parkinson’s symptoms
• however it was also observed that when people were given these drugs, they developed schizophrenic-like symptoms

Question 7

How was the idea that high levels of dopamine cause schizophrenia supported?

Answer 7

the idea was further supported by research into amphetamines
- this is a type of drug that is used recreationally to increase energy levels by increasing levels of dopamine

Question 8

Griffiths et al:
- what drug?
- what did he find?

Answer 8

found that when people were given dextroamphetamine (an amphetamine), they quickly developed paranoid delusions and a cold, detached, emotionless demeanour

Question 9

McKetin et al (2013):
- what did he find?

Answer 9

people who use amphetamines recreationally have reported psychotic-like side effects, including paranoia and mood disturbances

Question 10

Curran et al (2004):
- what did he find?

Answer 10

found that when people who have schizophrenia use amphetamines, their symptoms worsen

Question 11

Why was the initial dopamine hypothesis criticised?
How was is confirmed?

Answer 11

• for being too simplistic
• confirmed by the fact that giving drugs that lowered dopamine had no effect on those experiencing mainly negative symptoms

Question 12

Why was the original dopamine hypothesis complicated?

Answer 12

by the important discovery of different types of dopamine receptor sites in different parts of the brain

Question 13

Where were dopamine receptor sites discovered?

Answer 13

2 main areas of the brain?
- the mesolimbic pathway
- the mesocortial pathway

Question 14

Where is the mesolimbic pathway?

Answer 14

• a nerve pathway in the limbic system in the brain
• begins in the ventral regimental area (VTA) and ends in the nucleus acumbens

Question 15

What symptoms and state are in the mesolimbic pathway?

Answer 15

positive symptoms are thought to be associated with a HYPERdopaminergic state in the mesolimbic pathway

Question 16

What is too much dopamine in the mesolimbic pathway caused by and what does it cause?

Answer 16

• caused by neurons either firing too quickly or too often
• causes overstimulation and positive symptoms such as hallucinations

Question 17

What is poverty of speech linked to and where?

Answer 17

there is an excess of dopamine in the Broca’s area of the brain and it is thought that this may be linked to poverty of speech

Question 18

Where is the mesocortial pathway?

Answer 18

• a nerve pathway that begins in the limbic system and ends in the cortex (the outer layer of the brain)

Question 19

Where does the mesocortial pathway carry signals too and from?

Answer 19

carries signals from the VTA to the frontal lobe

Question 20

What is the frontal lobe involved in?

Answer 20

• planning
• decision-making

Question 21

What is the mesocortial pathway vital for?

Answer 21

• emotional responses
• emotions
• cognition

Question 22

What symptoms and state are thought to be linked to the mesocortial pathway?

Answer 22

negative symptoms are thought to be associated with a HYPOdopaminergic state in the mesocortial pathway

Question 23

What is too little dopamine evident in?

Answer 23

too little dopamine is evident in dopamine receptors in the frontal lobe of many people with cognitive impairments and negative symptoms of schizophrenia