Schizophrenia- Biological explanations for schizophrenia

Question 1

Genetics -

Answer 1

Genes consist of DNA strands. DNA produces ‘instructions’ for general physical features of an organism (such as eye colour, height) and also specific physical features (such as neurotransmitter levels and size of brain structures). These may impact on psychological features (such as intelligence and mental disorder). Genes are transmitted from parents to offspring. i.e. inherited.

Question 2

Dopamine -

Answer 2

A neurotransmitter that generally has an excitatory effect and is associated with the sensation of pleasure. Unusually high levels are associated with schizophrenia and unusually low levels are associated with Parkinson’s disease.

Question 3

Neural correlates -

Answer 3

Patterns of structure or activity in the brain that occur in conjunction with an experience and may be implicated in the origins of that experience.

Question 5

What evidence suggests that schizophrenia runs in families?

Answer 5

Schizophrenia has been noted to run in families, suggesting a genetic link, though family members also share environments.

Question 6

What is the relationship between genetic similarity and the risk of schizophrenia?

Answer 6

There is a strong relationship between the degree of genetic similarity and shared risk of schizophrenia, with higher genetic similarity correlating with higher risk.

Question 7

What percentage of genes do identical twins share?

Answer 7

Identical twins share 100% of their genes.

Question 8

What percentage of genes do siblings or parents share?

Answer 8

Siblings or parents share 50% of their genes.

Question 9

What did Irving Gottesman’s (1991) family study show?

Answer 9

Gottesman’s study showed a strong relationship between genetic similarity and the likelihood of developing schizophrenia.

Question 10

What are candidate genes in schizophrenia?

Answer 10

Candidate genes are individual genes believed to be associated with an increased risk of inheriting schizophrenia.

Question 11

Is schizophrenia polygenic?

Answer 11

Yes, schizophrenia is polygenic, meaning multiple genes each confer a small increased risk.

Question 12

What does it mean for schizophrenia to be aetiologically heterogeneous?

Answer 12

It means that different combinations of genetic factors can lead to the condition.

Question 13

What did Stephen Ripke et al. (2014) find in their genome-wide study of schizophrenia?

Answer 13

They found 108 genetic variations associated with increased risk of schizophrenia, including genes related to dopamine functioning.

Question 14

What is the dopamine hypothesis?

Answer 14

The dopamine hypothesis suggests that dopamine dysfunction in the brain is involved in schizophrenia.

Question 15

What is hyperdopaminergia in the subcortex?

Answer 15

Hyperdopaminergia refers to high levels or activity of dopamine in the subcortex, which may be linked to symptoms like auditory hallucinations.

Question 16

What is hypodopaminergia in the cortex?

Answer 16

Hypodopaminergia refers to low levels of dopamine in the prefrontal cortex, which may be linked to negative symptoms like poor decision-making.

Question 17

What are neural correlates?

Answer 17

Neural correlates are measurements of brain structure or function that correlate with specific experiences, such as schizophrenia symptoms.

Question 18

What neural correlate is associated with avolition?

Answer 18

Lower activity levels in the ventral striatum are a neural correlate of avolition, a negative symptom of schizophrenia.

Question 19

What did Juckel et al. (2006) find about the ventral striatum and negative symptoms?

Answer 19

They found lower activity levels in the ventral striatum in people with schizophrenia, correlating with the severity of negative symptoms.

Question 20

What neural correlates are associated with auditory hallucinations?

Answer 20

Reduced activity in the superior temporal gyrus and anterior cingulate gyrus is a neural correlate of auditory hallucinations.

Question 21

What did Allen et al. (2007) find about brain activity during auditory hallucinations?

Answer 21

They found lower activation levels in the superior temporal gyrus and anterior cingulate gyrus in people experiencing auditory hallucinations.

Question 22

What evidence supports genetic susceptibility to schizophrenia?

Answer 22

Evidence includes family studies like Gottesman (1991), adoption studies like Tienari et al. (2004), and molecular studies like Ripke et al. (2014).

Question 23

What did Pekka Tienari et al. (2004) find in their adoption study?

Answer 23

They found that children of people with schizophrenia were at heightened risk even when adopted into families with no history of schizophrenia.

Question 24

What is the role of dopamine agonists in schizophrenia?

Answer 24

Dopamine agonists, like amphetamines, worsen schizophrenia symptoms and can induce schizophrenia-like symptoms in non-diagnosed individuals.

Question 25

How do antipsychotic drugs work in relation to dopamine?

Answer 25

Antipsychotic drugs reduce dopamine activity, supporting the role of dopamine in schizophrenia.

Question 26

What did Lindstroem et al. (1999) find about dopamine production in schizophrenia?

Answer 26

They found that chemicals needed to produce dopamine are taken up faster in the brains of people with schizophrenia, suggesting higher dopamine production.

Question 27

What is the limitation of the dopamine hypothesis?

Answer 27

The dopamine hypothesis does not fully explain schizophrenia, as other neurotransmitters like glutamate may also play a role.

Question 28

What is the correlation-causation problem in neural correlates?

Answer 28

Neural correlates do not prove causation; unusual brain activity could be a cause, effect, or influenced by another factor.

Question 29

What is the role of mutation in schizophrenia?

Answer 29

Mutations in parental DNA, such as in paternal sperm cells, can increase the risk of schizophrenia, even without a family history.

Question 30

What did Brown et al. (2002) find about paternal age and schizophrenia risk?

Answer 30

They found a positive correlation between paternal age and schizophrenia risk, with risk increasing from 0.7% in fathers under 25 to over 2% in fathers over 50.

Question 31

What is the role of the psychological environment in schizophrenia?

Answer 31

Psychological factors, such as family functioning during childhood, may play a role, as biological factors alone do not fully explain schizophrenia.

Question 32

What does the probability of developing schizophrenia in identical twins suggest?

Answer 32

Even if one identical twin has schizophrenia, the other has less than a 50% chance of developing it, suggesting environmental factors also play a role.

Question 33

What is the current focus of schizophrenia research beyond dopamine?

Answer 33

Research has shifted to exploring the role of other neurotransmitters, such as glutamate.

Question 34

What does the mixed evidence for the dopamine hypothesis suggest?

Answer 34

It suggests that while dopamine is important, it is not the sole factor in schizophrenia, and other neurotransmitters are likely involved.

Question 35

What does the existence of neural correlates tell us about schizophrenia?

Answer 35

Neural correlates highlight brain systems that may not function normally but do not definitively explain the cause of symptoms.

Question 36

What is the significance of the Gottesman (1991) study?

Answer 36

It provides strong evidence for genetic vulnerability to schizophrenia by showing a clear relationship between genetic similarity and shared risk.

Question 37

What does the Ripke et al. (2014) study suggest about schizophrenia genetics?

Answer 37

It suggests that schizophrenia involves multiple genetic variations, including those related to dopamine and other neurotransmitters.

Question 38

What does the role of mutation in paternal sperm suggest about schizophrenia?

Answer 38

It supports the importance of genetic factors, as mutations in sperm can increase schizophrenia risk even without a family history.

Question 39

What does the correlation between ventral striatum activity and negative symptoms suggest?

Answer 39

It suggests that reduced activity in the ventral striatum may be linked to negative symptoms, but the exact causal relationship is unclear.

Question 40

What does the evidence for genetic and environmental factors suggest about schizophrenia?

Answer 40

It suggests that schizophrenia results from a combination of genetic susceptibility and environmental influences.

Question 41

What does the overemphasis on dopamine in schizophrenia research overlook?

Answer 41

It overlooks the potential role of other neurotransmitters and environmental factors in the development of schizophrenia.

Question 42

What does the study by Allen et al. (2007) suggest about auditory hallucinations?

Answer 42

It suggests that reduced activity in the superior temporal gyrus and anterior cingulate gyrus is associated with auditory hallucinations.

Question 43

What does the study by Juckel et al. (2006) suggest about negative symptoms?

Answer 43

It suggests that lower activity in the ventral striatum is associated with the severity of negative symptoms like avolition.

Question 44

What does the evidence from drug studies suggest about dopamine and schizophrenia?

Answer 44

Drug studies suggest that dopamine plays a significant role, as dopamine agonists worsen symptoms and antipsychotics reduce dopamine activity.

Question 45

What does the correlation between paternal age and schizophrenia risk suggest?

Answer 45

It suggests that mutations in paternal sperm, which increase with age, may contribute to the risk of schizophrenia.

Question 46

What does the role of glutamate in schizophrenia research indicate?

Answer 46

It indicates that dopamine is not the only neurotransmitter involved, and glutamate may also play a significant role.

Question 47

What does the evidence from adoption studies suggest about schizophrenia?

Answer 47

Adoption studies suggest that genetic factors are significant, as children of people with schizophrenia remain at higher risk even when raised in unaffected families.

Question 48

What does the mixed evidence for the dopamine hypothesis imply for treatment?

Answer 48

It implies that treatments targeting dopamine may not be sufficient, and other neurotransmitter systems should also be considered.

Question 49

What does the correlation-causation problem imply about neural correlates?

Answer 49

It implies that while neural correlates are useful for identifying brain abnormalities, they do not necessarily explain the cause of schizophrenia symptoms.

Question 50

What does the role of psychological factors suggest about schizophrenia?

Answer 50

It suggests that while biological factors are important, psychological and environmental factors also contribute to the development of schizophrenia.

Question 51

What does the evidence for genetic susceptibility and environmental factors suggest about schizophrenia?

Answer 51

It suggests that schizophrenia is a complex condition influenced by both genetic vulnerability and environmental triggers.