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Question 1

Genetic factors and cause of schizophrenia?

Answer 1

1. Being genetically related to someone with schizophrenia can significantly increase a person’s chances of developing it,
2. Family and twin studies have looked at concordance rates to surmise whether schizophrenia has a genetic basis.

Question 2

Gottesman (1991), method and findings?

Answer 2

1. Reviewed about 40 twin studies and found that with identical twins there was about a 48% concordance rate, i.e. there is a 48% chance that one MZ twin will have schizophrenia if the other does,
2. With non-identical twins the concordance rate was about 17%,
3. This is significant because, if it is assumed that MZ and DZ twins share the same amount of environmental influences, it means the reason for increased concordance is the genetic difference - MZ twins share 100% of their genes, compared to DZ who share 50%.

Question 3

Ripke et al. (2013), in support of a genetic explanation for schizophrenia?

Answer 3

1. Conducted a genome-wide study of 5,001 cases of Swedish nationals with schizophrenia and compared them to 6243 healthy controls,
2. The researchers found ‘22 loci associated at genome-wide significance; 13 of these are new, and 1 was previously implicated in bipolar disorder’, alongside 8,300 separate candidate genes,
3. Each candidate gene represents a genetic variation which marginally increases the risk of developing schizophrenia,
4. Therefore, schizophrenia is a polygenic disorder, i.e. has multiple, contributing candidate genes.

Question 4

Evidence for genetic basis of schizophrenia?

Answer 4

1. Shields (1962) found that MZ twins raised in different families still showed around 50% concordance,
2. Adoption studies found that if children are adopted because one or both of their biological parents has schizophrenia, the chance of them developing it stays the same. It suggests that genetics are more significant than the environment.

Question 5

Evidence against a genetic explanation for schizophrenia?

Answer 5

1. No study has found a 100% concordance rate between MZ twins, so schizophrenia can’t just be caused by genes. Shared environment may cause higher concordance rates in family studies because children imitate ‘schizophrenic’ behaviours,
2. This means other factors need to be considered, e.g. biochemical or psychological factors.

Question 6

Biochemical factors as a cause for schizophrenia?

Answer 6

1. Post-mortems and PET scans have shown that people with schizophrenia have abnormally high levels of dopamine,
2. These findings led to the development of the dopamine hypothesis, which states that synapses that use dopamine as a neurotransmitter are overactive in the brains of people with schizophrenia.

Question 7

Goldman Rakic et al. (2004), in support of the biochemical explanation of schizophrenia?

Answer 7

1. Suggested that hypodopaminergia (abnormally high dopamine levels) in the prefrontal cortex may be responsible for negative symptoms of schizophenia, such as speech poverty and avolition,
2. This is because the prefrontal cortex is associated with logical thinking, so abnormally high dopamine levels in this area may impair an individual’s ability to construct grammatical sentences that are focussed upon one topic (speech poverty) or the ability to make decisions about how to function in day to day living (avolition).

Question 8

Evidence for the biochemical explanation?

Answer 8

1. Antipsychotic drugs reduce the symptoms of schizophrenia by blocking dopamine receptors, this suggests that it is the overactive dopamine receptors causing the symptoms,
2. Drugs like amphetamines, which increase dopamine function, can sometimes cause schizophrenia-like symptoms in people without schizophrenia.

Question 9

Evidence against the biochemical explanation?

Answer 9

1. Antipsychotic drugs only work on the positive symptoms of schizophrenia, e.g. hallucinations. This means increased dopamine function doesn’t explain negative symptoms like social withdrawal,
2. The link with dopamine is correlational, so it doesn’t show cause and effect. It may be that increased dopamine function is a symptom of schizophrenia, rather than a cause of it.

Question 10

What is the neurological explanation of schizophrenia?

Answer 10

1. Neural correlates, such as abnormal brain structure, could explain schizophrenia.

Question 11

Juckel et al. (2006), in support of the neurological explanation?

Answer 11

1. Suggested that abnormally low levels of activation in the ventral striatum, when compared to healthy neurotypical controls, may be associated with the negative symptom of avolition,
2. This is because the ventral striatum is associated with evaluating reward values, predictability, and risks,
3. Therefore, low levels of activation and neurotransmission may mean that individuals cannot accurately assess the reward of having enough motivation to carry out normal day-to-day tasks, and so are, therefore, unable to cope with ‘normal’ life.

Question 12

Johnstone et al. (1976), evidence for the neurological explanation?

Answer 12

Johnstone et al. (1976) compared the size of the ventricles in the brain of people with schizophrenia with the brains of those without schizophrenia. They found that the people with schizophrenia had enlarged ventricles, which suggests that schizophrenia is linked to reduction in the temporal and frontal lobe volume,

Question 13

Buchsbaum (1990), evidence for the neurological explanation?

Answer 13

Buchsbaum’s (1990) MRI scans on the brains of people with schizophrenia found abnormalities in the prefrontal cortex.

Question 14

Evidence against the neurological explanation?

Answer 14

1. People without schizophrenia can also have enlarged ventricles, showing the relationship isn’t that simple,
2. These findings are correlational, so they don’t show cause and effect. It may be that abnormal brain structure is a symptom of schizophrenia, rather than a cause of it.

Question 15

Evolutionary explanation of schizophrenia?

Answer 15

1. Some evolutionary explanations of schizophrenia suggests that there must have been an advantage to having schizophrenia for it to remain in the population,
2. One evolutionary idea is that people diagnosed with schizophrenia today share similar characteristics to shamans of the past,
3. They were likely to lead people to split off from a group when it got too big, starting new cultures.

Question 16

Evidence for the evolutionary explanation?

Answer 16

There is such a strong genetic link to schizophrenia, that there must be some form of evolutionary explanation.

Question 17

Evidence against the evolutionary explanation of schizophrenia?

Answer 17

1. Generally discredited,
2. There is little evidence and the theory is difficult to prove.

Question 18

Schizophrenia as caused by psychological factors?

Answer 18

Three variations,
1. Family dysfunction cause,
2. Cognitive explanations,
3. Socio-cultural factors.

Question 19

The family dysfunction cause of schizophrenia?

Answer 19

1. Psychologists have suggested that conditions in dysfunctional families could cause schizophrenia,
2. One idea is that a cold and dominant ‘schizophrenogenic’ mother could cause conflict, causing schizophrenia,
3. Another idea is Bateson’s (1956) Double Bind theory, which suggested that faulty communication in families could lead to contradictory messages for children and cause schizophrenia,
4. Expressed emotion environments contain high levels of hostility and criticism towards the person with schizophrenia. EE has been found in dysfunctional families and correlates with relapse in people with schizophrenia.

Question 20

Fromm-Reichmann’s suggestion?

Answer 20

1. There is a classic, schizophrenogenic mother who is characterised as cold and rejecting,
2. This means that family climate is tense and lacking honesty, which leads to the development of paranoia and anxiety,
3. These feelings manifest themselves in the positive schizophrenic symptom of paranoid delusions.

Question 21

Vaughn and Leff (1976), findings in support of the expressed emotion explanation?

Answer 21

Found that people with schizophrenia were mroe likely to relapse once discharged from hospital in environments of high EE.

Question 22

Evidence for the family dysfunction explanation?

Answer 22

1. Other research investigating the role of the family on schizophrenia supports the theory of family dysfunction,
2. For example, Lidz et al. (1958) investigated families and proposed that dysfunctions such as emotionally distant parents and unequal marriages could have an impact on the children in the family, ultimately leading to schizophrenia.

Question 23

Evidence against the family dysfunction explanation?

Answer 23

1. The theory ignores the biological evidence for schizophrenia and puts the blame on the family and parents,
2. Most of the studies into the effects of family dysfunction were also retrospective - the families were only studied after the disorder had developed, and so it could have been the condition itself that had disrupted family life.

Question 24

The cognitive explanation for schizophrenia?

Answer 24

1. Cognitive psychologists argue that schizophrenia is caused by dysfunctional thought processing,
2. This leads to delusions, thought interference, language impairment, and memory problems.

Question 25

Neufeld (1978), for the cognitive explanation?

Answer 25

Neufeld (1978) compared the cognitive processes of people with schizophrenia with a control group. Participants with schizophrenia took longer to encode stimuli and showed short-term memory problems. This suggests their ability to process information was impaired,

Question 26

Meyer-Lindenberg et al. (2002), for the cognitive explanation?

Answer 26

Meyer-Lindenberg et al. (2002) found that people with schizophrenia did worse in a memory and reasoning task, showing reduced activity in the area of the brain associated with this.

Question 27

Evidence against the cognitive explanation?

Answer 27

1. Biochemical research suggests that cognitive problems are caused by increased dopamine function, rather than faulty information processing, 2. So, the faulty information processing may be a result of increased dopamine levels, meaning it is a symptom, not a cause of schizophrenia, 3. Cognitive explanations don't exclusively explain the cause of schizophrenia - they might need to be linked to biological explanations.

Question 28

Socio-cultural factors as an explanation?

Answer 28

1. The social causation hypothesis states that people with low social status are more likely to suffer from schizophrenia than people with higher social status, 2. It is thought that factors like poverty and discrimination cause high stress levels, and that this can cause schizophrenia.

Question 29

Evidence for the social-cultural factors explanation?

Answer 29

1. Harrison et al. (2001) found that people who were born in deprived areas were more likely to develop schizophrenia. This suggests that factors like poverty, unemployment, and crowding have an impact on schizophrenia.

Question 30

Evidence against the social-cultural factors explanation?

Answer 30

1. These results are correlational, so they don't show cause and effect, 2. The social drift hypothesis suggests that there are more people with schizophrenia in deprived areas because having schizophrenia gives them a lower social status, e.g. because they might be unemployed.

Question 31

The diathesis stress model explanation?

Answer 31

1. Proposes that people who are biologically vulnerable to developing a mental disorder may be more likely to develop it if they are subjected to certain social or environmental stressors, 2. Lots of research has been conducted in this area. The fact that concordance rates in twin studies aren't 100% indicates that there does seem to be some genetic link, but that other factors must play a role as well.