Biological explanation for Sz

Question 1

How are neurotransmitters passed across the synapse?

Answer 1

Neurotransmitter molecules are released from the end of the pre-synaptic neuron into the synapse. Having travelled across the synaptic gap, molecules are then taken up by receptors found on the post-synaptic neuron so that a chemical message can be passed on throughout the body.

Question 2

Effects of dopamine on Sz?

Answer 2

Increased dopamine receptors mean dopamine is up taken more which could account for positive symptoms of Sz such as delusions and hallucinations.

Question 3

Effects of serotonin on Sz?

Answer 3

Low serotonin increases dopamine levels. Therefore with Sz its thought people with low serotonin have high dopamine so experience positive symptoms. Low serotonin is associated with low moods and no motivation so negative symptoms of Sz such as apathy.

Question 4

Effects of GABA on Sz?

Answer 4

GABA is an inhibitory neurotransmitter therefore deceased levels of GABA increases dopamine levels. This causes symptoms.

Question 5

Effects of Glutamate on Sz?

Answer 5

Glutamate acts as an accelerator and a break which requires perfect conditions to work correctly. To little means dopamine levels are increased. Too much means dopamine levels are deceased.

Question 6

Excess dopamine: (3 ways)

Answer 6

1. Excess release of dopamine from the exon
2. Too many dopamine at the D2 receptor (binding site)
3. Overly sensitive receptors mean when they bind with dopamine they are more easily stimulated.

Question 7

The meso-limbic pathway

Answer 7

It is the brains reward pathway. The individual experiences a pleasurable stimuli through an experience they have encountered. This activates the meso-limbic pathway. This causes the nucleus of cells to release dopamine. Emotional and learning circuits are activated linking the stimulus to positive feelings. Over time the brain becomes desensitised meaning the same amount of dopamine will have less of an effect therefore more dopamine is needed in order to feel the same effects of pleasure. This leads to positive symptoms.

Question 8

The meso-cortical pathway

Answer 8

This pathway is linked to reward seeking and motivating behaviours. Sz is caused by a malfunction f the meso-cortical pathway. This explains why negative symptoms are first to appear with someone with Sz. Examples of these symptoms are apathy and social withdrawal.

Question 9

Strength - Lindstroem et al

Answer 9

Found that Sz used L-dopa faster than the control group, suggesting that they were producing more dopamine at a quicker rate. He used PET scans to establish this.

Question 10

Weakness - PET scans

Answer 10

PET scans are artificial and stress inducing therefore someone with Sz may have their symptoms worsened because they are placed in a stressful situation that causes their symptoms to become worse.

Question 11

Strength - PET scans

Answer 11

Standardised - scientific and objective

Question 12

Weakness - social factors

Answer 12

It ignores other possible factors to why someone might have Sz. For example childhood trauma and experiences and social stressors. This means that the explanation is incomplete and therefore reductionist.

Question 13

Strength - Carlsson

Answer 13

Found that dopamine, glutamate and serotonin are all implicated in the development of Sz showing neurotransmitters can explain the development of Sz.

Question 14

Strength - Post mortem

Answer 14

Falkai et al - Autopsies have found that people with Sz have a larger number of dopamine receptors than usual numbers in a typical brain.

Question 15

Positive applications

Answer 15

Drug treatment - FGA and SGA allow for both dopamine and serotonin to be treated.

Question 16

However

Answer 16

Rosa et al said that there is only a 50% compliance between patients and taking their medication. This means that the patient must want to get better or else they will not take their medication. Negative applications