It is hard to establish whether increased levels of dopamine is the cause of symptoms of schizophrenia or the increased dopamine is an effect of schizophrenia and the approach is regarded as too simple. In post mortem studies into Dopamine Beta Hydroxylase enzyme, an enzyme that breaks down dopamine and has been found in decreased levels in schizophrenia suffers, the cause of death or post mortem changes could be a cause of these low levels of the enzyme, making the reliability be questioned in post mortem studies. Support for the Dopamine hypothesis is found in amphetamine studies, amphetamine increases the concentration of dopamine in the synoptic gap, amphetamine increases hallucinations in non-schizophrenic controls and in schizophrenic suffers abnormally large responses have been found to low amphetamine doses. This supports the dopamine hypothesis; more specifically the argument for schizophrenic suffers having more sensitive dopamine receptors. Further support is that schizophrenia symptoms can be treated effectively in 60% of cases with dopamine antagonists, more affective on positive symptoms, showing a link between dopamine levels and positive symptoms in schizophrenic suffers.
It is hard to establish whether increased levels of dopamine is the cause of symptoms of schizophrenia or the increased dopamine is an effect of schizophrenia and the approach is regarded as too simple. In post mortem studies into Dopamine Beta Hydroxylase enzyme, an enzyme that breaks down dopamine and has been found in decreased levels in