Schizophrenia - biological explanations Flashcards

1
Q

What are the 2 main biological explanations of schizophrenia

A

Genetic inheritance, neural correlates (hyperdopaminergia)

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2
Q

What is genetic inheritance primarily about

A

Function of C4 gene, twin studies, adoption studies

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3
Q

What is neural correlates (hyperdopaminergia) primarily about

A

Revised dopamine hypothesis, further neural correlates

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4
Q

How is schizophrenia genetically inherited

A

Genetic predisposition through faulty genes, C4 mainly which was discovered by Ripke et al. Mainly consist of biochemical imbalances or brain structure abnormalities

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5
Q

What is the function of the C4 gene

A

Found at synapses in CNS and mediates pruning. If fault, can lead hyper-pruning which leads to symptoms of schizophrenia

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6
Q

What does the understanding of the C4 gene causing SZ allow us to understand

A

Sufferers of SZ have thinner cerebral cortex’s with fewer synapses

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7
Q

According to Gottesman and Shields (1991) What are the chances of a child, (100% genetic similarity) of 2 SZ patients, to develop SZ

A

46%

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8
Q

According to Gottesman and Shields (1991) What are the chances of an identical twin, (100% genetic similarity) of which 1 has been diagnosed with SZ, to develop SZ

A

48%

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9
Q

According to Gottesman and Shields (1991) What are the chances of a first degree relative, (child) (50% genetic similarity) of 1 SZ patient, to develop SZ

A

13%

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10
Q

According to Gottesman and Shields (1991) What are the chances of a second degree relative, (grandchild) (25% genetic similarity) of 1 SZ patients, to develop SZ

A

5%

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11
Q

Why are twin/adoption studies used to investigate genetic inheritance

A

Isolate nature from nurture

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12
Q

What advantages do adoption studies have over twin studies

A

Can separate nature/nurture better as children are not raised by biological parents

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13
Q

What did MacDonald and Schultz (2009) find in their twin study

A

In MZ twins, if one is diagnosed with SZ, the other is 99x more likely to suffer from SZ

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14
Q

What did Tienari et al (2000) find in his adoption study

A

164+ adopted kids from Finland, whose mothers had SZ. Matched with kids whose mothers didn’t suffer from SZ. 7% oh those with SZ mothers had also been diagnosed with SZ, compared to 2% from other group.

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15
Q

What did Joseph (2004) find as supporting research of the biological explanations

A

40% concordance rate of SZ in MZ twins, 7% in DZ twins

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16
Q

What is a negative evaluation point for biological explanations

A

Don’t take into account environment - stress, alcohol, childhood etc, therefore an incomplete explanation

17
Q

What are neural correlates

A

Where brain structure differences correlate with psychological disorders and symptoms e.g enlarged ventricles

18
Q

What does the dopamine hypothesis state

A

Elevated levels of dopamine at post synaptic level are due to not enough being broken down during synaptic transmission, leaving too much in surrounding cells. Re - uptake processes may be impaired so too much dopamine in synapse. Presynaptic neurone release too much dopamine

19
Q

What does the revised dopamine hypothesis state

A

No D2 receptors in pre frontal cortex despite dopamine deficiency in region, which is responsible for negative symptoms. This is known as HYPOdopaminergia

20
Q

What did Randrup and Munkvad (1966) find as supporting research for neural correlates

A

Rats given dopamine amphetamines to increase levels 3 times per day for 6 days. Then showed lasting abnormalities such as attentional issues, a key symptom of SZ

21
Q

What is a negative evaluation point for neural correlates

A

Incomplete explanation - antipsychotics to reduce and correct dopamine levels are 85% effective, so why not 100%? Must be other factors

22
Q

What are further neural correlates

A

Brain structure and biochemistry

23
Q

What are the forms of brain structure and biochemistry as further neural correlates

A

Enlarged ventricles - link to negative symptoms

Hypofrontality - Reduced activity in cortex of frontal lobes, negative symptoms

Hippocampus/amygdala - Decreased volume has been linked to negative symptoms