Schizotypal traits in healthy women predict prefrontal activation patterns during a verbal fluency task: A near-infrared spectroscopy study

Background/Aims: Previous functional neuroimaging studies have reported that patients with schizophrenia show reduced prefrontal activation during cognitive tasks whereas patients with schizotypal personality disorder (SPD) show preserved or even increased right prefrontal activation, compared to healthy controls; on the other hand, reduced hemispheric laterality is considered to be common to these two disorders. The aim of this study was to examine the possible association between schizotypal traits at a nonclinical level and prefrontal activation patterns during a letter version of the verbal fluency task (VFT). Methods: We examined the relationships of schizotypal traits as measured by the Schizotypal Personality Questionnaire (SPQ) in a nonclinical female population with prefrontal activation patterns during the VFT, using near-infrared spectroscopy. Twenty-seven healthy participants were divided into high (n = 14) and low (n = 13) SPQ groups by the median split of the total SPQ score. Results: Compared to the low SPQ group, the high SPQ group showed significantly larger right prefrontal activation during the performance of the VFT, leading to more bilateral activation. Conclusion: Our results suggest that schizotypal traits at a nonclinical level may be related to relative right prefrontal laterality with overall prefrontal activation being preserved, consistent with previous findings obtained by studies of patients with SPD.