11309173
Description
Mind Map by Grace Fawcitt, updated more than 1 year ago
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Created by Grace Fawcitt
about 7 years ago
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Biological Explanations
of Schizophrenia
- Genetic Basis
- Runs in families
- Concordance rates
- Gottesman
- 48% MZ twins
- 100% shared genes
- 100% shared genes
- 17% DZ twins
- 6% siblings
- 1% general
population
- 48% MZ twins
- Gottesman
- Candidate genes
- Ripke et al 2014
- 108 separate variations
- Some coded for dopamine
- Some coded for dopamine
- 108 separate variations
- Ripke et al 2014
- Polygenic
- Multiple genes involved in
onset of schizophrenia
- Multiple genes involved in
onset of schizophrenia
- Discussion
- - Twin studies seen as weak as MZ twins also
share their environment e.g. wear same clothes,
treated same by parents
- This is an issue as it indicates that
schizophrenia may not have a solely
genetic basis
- Confounding variable
- This is an issue as it indicates that
schizophrenia may not have a solely
genetic basis
- - The problem with having so many candidate
genes is one cause cannot be identified,
meaning an effective treatment is very
difficult to create
- Evidence suggests genes do
play a role in the onset of
schizophrenia, but are not the
sole cause
- - Twin studies seen as weak as MZ twins also
share their environment e.g. wear same clothes,
treated same by parents
- Runs in families
- Dopamine hypothesis
- Hyperdopaminergia
- Sub
cortex
- Broca's area
- Speech production
- High level of dopamine receptors
- High activity levels
- High activity levels
- Speech production
- Broca's area
- Positive symptoms
- Auditory hallucinations
- Disorganised speech
- Auditory hallucinations
- Sub
cortex
- Hypodopaminergia
- Cortex
- Pre-frontal cortex
- Planning and decision making
- Low activity levels
- Planning and decision making
- Pre-frontal cortex
- Negative symptoms
- Avolition
- Social withdrawal
- Avolition
- Cortex
- Could occur simultaneously, hence the
combination of symptoms
- Discussion
- Evidence
- Curran et al. 2004
- Dopamine agonists can produce schizophrenic symptoms
- Amphetamines
- Increase levels of dopamine
- Supports hyperdopaminergia
- Positive symptoms
- Amphetamines
- Dopamine agonists can produce schizophrenic symptoms
- Tauscher et al. 2014
- Dopamine antagonists can reduce schizophrenic symptoms
- Antipsychotics
- Reduce dopamine levels in the brain
- Antipsychotics
- Dopamine antagonists can reduce schizophrenic symptoms
- Ripke et al.
- Found that some genes associated with
schizophrenia did not code for dopamine, but
for glutamate instead
- Suggests dopamine is not the sole cause
of schizophrenia; other
neurotransmitters may also play a role
- Incomplete explanation
- Suggests dopamine is not the sole cause
of schizophrenia; other
neurotransmitters may also play a role
- Found that some genes associated with
schizophrenia did not code for dopamine, but
for glutamate instead
- Curran et al. 2004
- Evidence
- Hyperdopaminergia
- Neural correlates
- Abnormalities in structure/function
of the brain
- Negative symptoms
- Ventral striatum
- Anticipation of reward
- Low levels of activity
- Jukel et al. 2006
- Anticipation of reward
- Ventral striatum
- Positive symptoms
- Superior temporal gyrus
- Temporal lobe
- Sound processing
- Temporal lobe
- Anterior cingulate gyrus
- Behaviour regulation
- Behaviour regulation
- Low activity levels were found in patients
suffering hallucinations
- Made more errors when identifying
pre-recorded speech as theirs
- Made more errors when identifying
pre-recorded speech as theirs
- Superior temporal gyrus
- Discussion
- Unsure if neural
correlates are
the cause or the
effect of
schizophrenia
- Use of brain scans
- Objective and highly controlled
- Objective and highly controlled
- Biologically deterministic
- Unsure if neural
correlates are
the cause or the
effect of
schizophrenia
- Abnormalities in structure/function
of the brain
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