Evaluate the dopamine hypothesis explanation for Schizophrenia (8)

This explanation looks at how dopamine deficiency can explain Sz. Dopamine regulates mood and attention. The dopamine hypothesis states that an access number of dopamine synapses results in Sz. This overactivity of the synapse is associated with paranoia and hallucinations. Over stimulation of the mesolimbic pathway is linked to positive symptoms Problems with the dopamine functioning in the mesocortical pathway is associated with negative symptoms and this therefore explains how Sz is developed.
There is supporting evidence for this explanation. This comes from Randrup and Munkvad who raised dopamine levels in the brain of rats by injecting them with amphetamines. Their behaviour became consistent with that of schizophrenics as they became isolated and aggressive. He therefore concluded that excess amounts of dopamine in the brain leads to schizophrenic behaviour which gives this explanation credibility. However, there has been issues with the supporting evidence he use of animal studies such as Randrup and Mudavadi have issues. This is because humans and rats are inherently different as rats have more chromosomes than humans so generalisations are difficult. The brain structures of rats is also different to humans so it is arguably not representative.