Biological Explanations Flashcards

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1
Q

How are candidate genes involved in SZ?

A
  • early research looked for a single gene involved
  • found to be polygenic
  • Ripke (2014) —> genetic makeup of 37,000 ppl compared w 113,000 controls
  • found 108+ genes associated w higher risk of SZ
  • aetilogically heterogenous = caused by diff combos of genes
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2
Q

How are genetics involved in SZ development?

A
  • found to have a genetic basis; chance of developing SZ increases w genetic similarity to someone w disorder
    ~ MZ twins : 48%
    ~ DZ twins : 17%
    ~ general population : 1%
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3
Q

What are neural correlates?

A

Measuring structures/function of the brain that correlates with a behaviour or experience

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4
Q

Outline the dopamine hypothesis

A
  • suggests dysregulated dopamine system contributes to positive, negative and cognitive symptoms of SZ
  • can be hyperdopaminergia (too high) or hypodopaminergia (too little)
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5
Q

Describe the neural correlate for high levels of dopamine

A

Hyperdopaminergia
- area : subcortex, specifically between dopamine pathways and Broca’s area
- function of area : speech production
- symptom : speech poverty + auditory hallucinations

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6
Q

Describe the neural correlate for low levels of dopamine

A

Hypodopaminergia
- area : prefrontal cortex
- function of area : responsible for logical thinking and decision-making
- symptoms : negative symptoms (e.g. avolitions)

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7
Q

Describe the neural correlate leading to symptom of abolition

A

Ventral striatum = involved in process of motivation and reward

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8
Q

Outline research supporting neural correlates

A

Juckel et al
- finding 1 —> activity levels (fMRI) in ventral striatum were lower in SZ than controls during reward anticipation
- finding 2 —> lower activity levels in ventral striatum correlated w severity of neg symptoms

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9
Q

What are issues with biological explanation of SZ?

A

Biologically reductionist
- only focuses on genetic, neuro chemical and brain structural components
- ignored other potential factors
- e.g. trauma (67% of SZ patients reported traumatic event vs 38% in other non-psychotic mental health issues), smoking cannabis (x7 risk), family environment, birth complications
- MZ twins are not 100% so cannot be entirely genetic
Bidirectional ambiguity
- unclear whether altered dopamine levels cause SZ or whether experience of SZ results in altered dopamine regulation

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10
Q

What are strengths of the biological explanation of SZ?

A

Treatments
- genetic counselling —> helps people understand genetic condition in family, helps making choices about having children or future development of SZ
- typical and atypical antipsychotics —> block dopamine receptors at synapse, reduce action of dopamine
- success of treatments suggests dopamine is involved in SZ symptoms
however
- some atypical psychotics also work on serotonin and glutamate
- some post mortem + brain scans found high levels of glutamate in SZs
- suggests DA hypothesis = incomplete as other neurotransmitters involved

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