First 315 words of the document:
Biological explanations for schizophrenia- dopamine hypothesis
The positive symptoms of schizophrenia are caused by too much activity in the
dopamine pathways which is due to having too many D2 receptors. Dopamine
neurones affect attention which could account for the disturbances in attention,
perception and thought processes.
Amphetamines- increase dopamine levels as they stimulate dopamine
neurones to release dopamine into the synapse leading to hallucinations,
delusions. This shows that high activity in dopamine pathways can lead to
the positive symptoms.
Those who suffer from Parkinson's disease are given a chemical called
L-Dopa which increases dopamine levels as they don't have enough dopamine
leading to symptoms of schizophrenia. This show that high activity in
dopamine pathways can lead to the positive symptoms.
Phenothiazines (antipsychotics)- block dopamine receptor and reduce the
attention deficit in schizophrenia. This suggests that D2 receptors increase
activity in dopamine pathways and can cause the positive symptoms.
Only explains the positive symptoms (simplistic)- the new atypical
antipsychotics also influence serotonin levels and are slightly more
effective at treating the negative symptoms. Therefore schizophrenia can
have multiple causes.
Deterministic nature leads to useful treatments- the dopamine hypothesis
is deterministic as there is no free will over having too many dopamine
receptors and therefore too much activity. This means that it is easier to
treat as the cause is clear.
Reductionist- only focuses on dopamine so other factors such as
ventricles and childhood experiences causing stress, so we only have a
limited understanding of the causes of schizophrenia.
/ Relationship to genes- genes and dopamine activity may be linked and
ultimate genes may be the cause of schizophrenia whilst dopamine would be
the proximate cause.