DRD2 and psychotic disorder: To name a few examples, studies of dopaminergic function in psychosis and schizophrenia have collectively shown increased dopamine synthesis and release capacity as indexed by increased [18F]DOPA uptake and more pronounced amphetamine-induced decreases in D2-R receptor binding, a small increase in striatal D2-R availability and lower D2-R availability in the thalamus [6, 7].