The dopamine hypothesis has been the major pathophysiological theory of
psychosis in recent decades. Molecular imaging studies have provided
in vivo evidence of increased dopamine synaptic
availability and increased presynaptic dopamine synthesis in the striata of
people with psychotic illnesses. These studies support the predictions of
the dopamine hypothesis, but it remains to be determined whether
dopaminergic abnormalities pre-date or are secondary to the development of
psychosis. We selectively review the molecular imaging studies of the
striatal dopaminergic system in psychosis and link this to models of
psychosis and the functional subdivisions of the striatum to make
predictions for the dopaminergic system in the prodromal phase of
psychosis