Amphetamine-induced striatal dopamine release in schizotypal personality disorder

Rationale: Previous research has suggested that schizotypal personality disorder (SPD), a condition that shares clinical and cognitive features with schizophrenia, may be associated with elevated striatal dopamine functioning; however, there are no published studies of dopamine release within subregions of the striatum in SPD. Objectives: To characterize dopamine release capacity in striatal subregions and its relation to clinical and cognitive features in SPD. Methods: We used positron emission tomography with [¹¹C]raclopride and an amphetamine challenge to measure dopamine D2-receptor availability (binding potential, BP_ND), and its percent change post-amphetamine (∆BP_ND) to index amphetamine-induced dopamine release, in subregions of the striatum in 16 SPD and 16 healthy control participants. SPD participants were evaluated with measures of schizotypal symptom severity and working memory. Results: There were no significant group differences in BP_ND or ∆BP_ND in any striatal subregion or whole striatum. Among SPD participants, cognitive-perceptual symptoms were associated at trend level with ∆BP_ND in the ventral striatum, and disorganized symptoms were significantly negatively related to ∆BP_ND in several striatal subregions. Conclusions: In contrast to previous findings, SPD was not associated with elevated striatal dopamine release. However, in SPD, there was a moderate positive association between ventral striatal dopamine release and severity of cognitive-perceptual symptoms, and negative associations between striatal dopamine release and severity of disorganized symptoms. Future larger scale investigations that allow for the separate examination of subgroups of participants based on clinical presentation will be valuable in further elucidating striatal DA functioning in SPD.