Schizophrenia - Biological And Neural Explanations

Question 1

What are the 3 Biological Explanations?

Answer 1

Genetic Vulnerability
Dopamine Hypothesis
Neural Correlates

Question 2

What are the different sub categories of Genetic Vulnerability

Answer 2

Family studies
Twin studies
Adoption studies
Candidate Gene

Question 3

Explain family studies?

Answer 3

Gottesman (1991) Family studies
His findings showed that the greater the degree of genetic relatedness, the greater risk of developing schizophrenia
But identical twins were only about 48% so there is still a great environmental impact

Question 4

Explain twin studies?

Answer 4

Twin studies
Gottesman and shields (1962) found that the concordance rate for schizophrenia in MZ twins was 48% compared for 17% for DZ twins
Suggesting that schizophrenia has a genetic basis
Joseph (2004) showed a concordance rate of 40.4% for MZ and 7.4% for DZ

Question 5

Explain the first adoption study?

Answer 5

Heston (1966) compared 47 adopted children whose biological mothers had schizophrenia with a control group with no family history of schizophrenia
0 in the control group was diagnoses with schizophrenia 16% of the offsprings of the sample were diagnoses

Question 6

explain the second adoption study?

Answer 6

Tienari (2000)
Found that 11% of 164 adoptees whose mothers had schizophrenia also had schizophrenia

Question 7

Explain the candidate Gene?

Answer 7

Schizophrenia is thought to be polygenic (many genes make up the disorder)
Ripke (2014) completed a study combining all data from a genome wide study of schizophrenia
37000 patients were compared to 113,000 controls
108 separate genetic variations were associated with an increased risk of schizophrenia

Question 8

What is the word for many genes being the cause of something?

Answer 8

Polygenic

Question 9

What is important to remember about the dopamine hypothesis?

Answer 9

It was originally just hyper and hen adapted to include hypo

Question 10

What is the theory of the Dopamine Hypothesis?

Answer 10

This theory claims that excessive amounts of dopamine or an oversensitivity of the brain dopamine is the cause of schizophrenia.
So messages from neurons that transmit dopamine fire too easily or too often, leading to the characteristic symptoms of schizophrenia.

However, it was adapted to include the effects of lower levels of dopamine

Question 11

What is the general overview of the dopamine hypothesis?

Answer 11

An excess of the neurotransmitter dopamine has been implicated in the symptoms of schizophrenia
Hyperdopaminergia in the subcortex
Hypodopaminergia in the cortex

Question 12

What is the ending of that long word?

Answer 12

Dopamine rgia

Question 13

Where may hyperdopaminegia occur?

Answer 13

The sub cortex

Question 14

Where may hypodopaminegia occur

Answer 14

Cortex

Question 15

Explain hyperdopaminegia in the subcortex?

Answer 15

Higher levels of dopamine in the subcortex
So there is excess levels of dopamine receptors in Brocca’s area. This may be the cause of the disorganised speech (as brocca’s area is overexcited)
Furthermore, as there is excess dopamine in the subcortex his could explain the experience of auditory hallucinations

Question 16

Explain hypodopaminegia in the cortex?

Answer 16

Lower levels of dopamine in the brain’s cortex
Goldman and Rakic et al (2004) identified that low levels of dopamine in the prefrontal cortex
It will increase the negative symptoms of schizophrenia as it effects thinking and decision making

Question 17

Explain in great detail how the dopamine hypothesis and schizophrenia interact?

Answer 17

• People with schizophrenia are thought to have abnormally high numbers of D2 receptors on receiving neurons, resulting in more dopamine binding and therefore more neurons firing

Question 18

What 3 things can be used as evidence for the dopamine hypothesis?

Answer 18

Amphetamines
Cocaine
Antipsychotic drugs

Question 19

Explain the evidence of the DH: Amphetamines

Answer 19

➢ Amphetamines; this is a dopamine agonist, this stimulates nerve cells containing dopamine causing the synapse to be ‘flooded’ – large doses of the drug can cause hallucinations and delusions of a schizophrenic episode.

Question 20

Explain the evidence of the DH: Cocaine

Answer 20

➢ Cocaine also increases the levels of dopamine in the brain and can cause the positive symptoms of schizophrenia and exaggerate them in people who already have the disorder.

Question 21

Explain the evidence of the DH:

Answer 21

➢ Antipsychotic drugs (dopamine antagonists) which block the activity of dopamine in the brain, by reducing the stimulation of the dopamine system, eliminates hallucinations and delusions. By alleviating many of the symptoms of schizophrenia, antipsychotic drugs strengthen the case for dopamine being a significant contributory factor.

Question 22

What is an agonist?

Answer 22

An agonist is a chemical that binds to a receptor of a cell and triggers a response by that cell.

Question 23

What is a antagonist

Answer 23

An antagonist blocks or reduces the effect of a neurotransmitter

Question 24

What drug can be used to treat Parkinson’s

Answer 24

L Dopa

Question 25

Why may Parkinson’s be confused with schizophrenia?

Answer 25

The disease increases dopamine

Question 26

Explain post mortem evidence for the dopamine hypothesis?

Answer 26

• Post mortems of schizophrenics, show an increase of dopamine in parts of the brain. (Seeman 1987)

Question 27

What are Neural Correlates?

Answer 27

• Neural correlates are measurements of the structure or function of the brain that occur in conjunction with an experience

Question 28

What is a newer approach to Schizophrenia?
How?

Answer 28

• There is growing evidence that schizophrenia is down to structural abnormalities in the brain
• Brain scanning techniques have made it possible to investigate living brain images
People with schizophrenia have abnormally large ventricles in the brain. Ventricles are fluid filled cavities. This means that the brains of people with schizophrenia are lighter than normal.

Question 29

What section of the brain is linked with Neural Correlates of Schizophrenia Negative Symptoms?

Answer 29

Ventral Striatum

Question 30

Explain Neural Correlates of Schizophrenia negative symptoms

Answer 30

Activity in the ventral striatum has been linked to the development of avolition (loss of motivation)
The ventral striatum are believed to be particularly involved in the anticipation of a reward for certain (2006) found lower levels compared to control
Negative correlation between activity levels in the ventral striatum and the severity of overall negative symptoms

Question 31

What section of the brain is linked with Neural Correlates of Schizophrenia Positive Symptoms?

Answer 31

Reduced activity in the superior temporal gyrus and anterior cingulate grus

Question 32

Explain Neural Correlates of Schizophrenia positive symptoms

Answer 32

Reduced activity in the superior temporal gyrus and anterior cingulate grus have been linked to the development of auditory hallucinations
Studies show that patients experiencing auditory hallucinations showed lower activations levels in these areas than controls

Question 33

What studies can be used as supporting evidence for a genetic basis?

Answer 33

• Genetic links - Gottesman (1991)
• Adoption studies- Tienari et al. (2004)
• Genetic variation- Ripke et al. (2014)

Question 34

Explain the evaluations of twin studies?

Answer 34

• Twin studies demonstrate that there may be a predisposition to develop schizophrenia, however, the fact that both twins do not always develop schizophrenia means that environmental factors must also play a part
Sample sizes are small so they can’t be generalised

The higher concordance rates between MZ twins could be explained by environmental similarities not genetics
MZ twins elicit more similar treatment than DZ twins
There isn’t yet one gene which haas been found to be causing schizophrenia
Many studies in this areas lack temporal validity (Using DSM III etc)

Question 35

Explain the evaluations of Adoption Studies

Answer 35

Tienari conducted his study within Finland, therefore we are not able to generalise this study to the rest of the world

Question 36

What are the general evaluations?

Answer 36

Ignorance of psychological explanation

Question 37

Explain the evaluation for the dopamine hypothesis?

Answer 37

Mixed Evidence for the dopamine hypothesis
• Curran et al. (2004) found that dopamine agonists increase the levels of dopamine and can make the symptoms of schizophrenia worse.
• Tauscher et al. (2014) found that antipsychotic drugs reduce the levels of dopamine.

• Lindstoroem et al. (1999) found that the chemicals needed to produce dopamine are taken up faster in the brains of people with schizophrenia – suggesting they produce more dopamine.
• Moghaddam and Javitt (2012) have found evidence for the role of a neurotransmitter called glutamate which indicates more signalling to other cells which could induce symptoms of schizophrenia

Question 38

What are the evaluations for Neural Correlates?

Answer 38

Correlation or Causation
General

Question 39

Explain the negative evaluation of general bio/neural explanations…

Answer 39

Ignorance of the psychological explanation
• It is a reductionist approach
• Family functioning during childhood may play a role or another “diathesis stress” relationship
• In terms of inheritance – less than 50% chance of developing schizophrenia if your identical twin has schizophrenia

Question 40

Explain the evaluation of Neural Correlates: Correlation or Causation

Answer 40

• Neural correlations tell us very little about causes of schizophrenia
• The correlation between the ventral striatum and negative symptoms could suggest that there is something wrong in the ventral striatum which is causing negative symptoms or that the negative symptoms mean less information passes through the striatum.

Question 41

Explain the evaluations of Neural Correlates: General

Answer 41

• Findings are inconsistent and therefore inconclusive

• MRIs have made it possible to investigate living brain images which is an
advance on merely having to rely on post mortems

Question 42

Explain the evaluation for a genetic basis: Mutations

Answer 42

• There is evidence of mutations in parental sperm.
• Caused by radiation, poison or viral infection
• Brown et al. (2002) – positive correlation between paternal age
and risk of schizophrenia
• Increasing from around 0.7% fathers under 25 and 2% in fathers over 50