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Psychology unit 4 schizophrenia revision
Biological explanations for schizophrenia- dopamine hypothesis
Positive symptoms are causes by too much activity in the dopamine pathways which
is due to having too many D2 receptors. Dopamine neurons affect attention which
could account for disturbances in attention, perception and thought processes.
Amphetamines increase dopamine levels as they stimulate dopamine neurons
to release dopamine into the synapse causing hallucinations and delusions.
This shows that high activity in the dopamine pathways can lead to positive
Parkinson's disease sufferers are given L-Dopa which increases dopamine
levels as they don't have enough dopamine leading to them showing some
positive symptoms. This shows that high activity in dopamine pathways can
lead to positive symptoms.
Antipsychotics block dopamine receptors and reduce attention deficit in
schizophrenics. Therefore D2 receptors increase activity in dopamine
pathways leading to positive symptoms.
Only explains positive symptoms (simplistic)- new atypical antipsychotics
also influence serotonin levels and are slightly more effective. This shows
that the symptoms of schizophrenia have multiple causes.
Deterministic nature of explanation can lead to useful treatments- no
free will over having too many D2 receptors in the brain and therefore
having too much activity there. However, this means that it is easier to
treat as the aim of the treatment is clear.
Reductionist- only focuses on dopamine so other factors such as
ventricles or childhood experiences are ignored giving a limited
understanding of the causes of schizophrenia.
Correlational evidence- evidence supporting the dopamine hypothesis is
correlational. They show that dopamine is linked to the positive symptoms
but don't show that it is the cause of positive symptoms.
/ Relationship with genes- genes and dopamine activity may be linked
and ultimate genes may be the cause of schizophrenia whilst dopamine may
be the proximate cause.