What is dopamine? 

Dopamine is a neurotransmitter that is important for emotional and cognitive processing in the brain, particularly rewarding and pleasurable stimuli or experiences. Alterations of the dopamine system have been suggested in schizophrenia. This may be assessed as changes in levels of dopamine or its metabolites, or as changes in levels or activity of the mechanical components of the dopamine system, such as the receptors that receive dopamine, or the transporters that remove it.

What is the evidence for dopamine?

Moderate quality evidence suggests elevated striatal dopamine synthesis and release capacities and increased synaptic dopamine levels in people with schizophrenia compared to controls. The finding for dopamine synthesis was apparent in treatment-responsive and treatment-naive patients, but not in treatment-resistant patients. There were no differences in dopamine D2/3 receptor or transporter availability. Within-group variability was similar in patient and control groups for dopamine synthesis and release capacities, but there was greater variability in synaptic dopamine levels, and in dopamine D2/3 receptor and transporter availability in the patient groups.

Moderate to low quality evidence suggests an association between dopamine receptor occupancy and clinical improvement on the PANSS following treatment with antipsychotic medications. Greatest D2 receptor occupancy occurs with haloperidol (91.9%), then risperidone, olanzapine, clozapine, quetiapine, aripiprazole, ziprasidone, and then amisulpride (85%).

October 2020

Last updated at: 4:22 am, 21st October 2020
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