Dopamine hypothesis

Dopamine is a neurotransmitter ad unusually high levels are associated with sz where unusually low levels are associated with Parkinson’s.

Neurons that use dopamine fre or often and transmit too many messages, therefore a schizophrenic has higher than usual amounts of dopamine in the brain.

Research suggests an excess presence of dopamine receptors at the synapse is associated with sz.

It is possible that in increase on the mesolymbic pathway (reward pathway) is associated with positive symptoms

An ncrease of dopamine in the mesocortical pathway contributes to negative symptoms.

Now more recent research into dopamine hypothesis looks and hyperdopaminergia. his is an abnormal amount of dopamine in the cortex eg pre frontal cortex which is responsible for decision making.

Evaluation

Practical applications - antipsychotics that block dopamine at the synapse. Qualitty of life and economy.

Further evidence for this theory. People with Parkinson’s are assigned a drug that increase dopamine but this can make them develop sz like symptoms which supports this.

Donnelly studies homovanillic acid which is a waste product of dopamine passed out of the body and sz had more of this in their waste than non sz. Supports as it suggests they produce more dopamine than the average person.

Causality issues does sz cause excess dopamine or does excess dopamine cause sz.