Neural correlate of impulsivity in subjects at ultra-high risk for psychosis

Abstract

Objective: Impulsivity is one of the most commonly reported behavioral characteristics of patients with schizophrenia. Although there is accumulating evidence regarding behavioral problems in individuals at ultra-high risk (UHR) for psychosis, as yet, no study has reported on impulsivity in this population. The aim of the present study was to assess impulsivity in UHR subjects and to investigate the associated gray matter correlates.

Method: This study included 32 UHR subjects and 32 age- and gender-matched healthy controls (HCs). The Barratt Impulsiveness Scale version-11 (BIS-11) was employed to assess impulsivity. Differences between the groups in gray matter volume in the anterior cingulate cortex (ACC), dorsolateral prefrontal cortex (DLPFC), and orbitofrontal cortex (OFC) were assessed. Then, a correlational analysis between the BIS-11 scores and significant clusters of gray matter volume was conducted in UHR subjects.

Results: UHR subjects were more impulsive than HC subjects in terms of attention (t = 3.5187, p<0.01), motor (t = 3.1751, p<0.01), and non-planning (t = 4.4154, p<0.01) scores. The gray matter volume of the ACC was negatively correlated with the motor (r = -0.472, p<0.01) and non-planning (r = -0.354, p = 0.04) scores of the BIS-11 in UHR subjects.

Conclusion: These results suggest that impulsivity in UHR subjects may reflect altered integrated conflict processing, which likely stems from abnormalities in the ACC, rather than altered reward/punishment processing or executive control.

Keywords: ACC; ADHD; APS; Anterior cingulate; BIPS; BIS-11; BPD; Barratt impulsiveness scale, version-11; DLPFC; GRD; HC; Impulsivity; K-WAIS; Korean version of the Wechsler Adult Intelligence Scale; OFC; ROI; SCID-I; SCID-NP; SIPS; Structured Clinical Interview for DSM-IV Axis I; Structured Clinical Interview for DSM-IV Axis I Non-Patient version; Structured Interview of Prodromal Symptoms; UHR; Ultra-high risk for psychosis; VBM; Voxel-based morphometry; anterior cingulate cortex; attention-deficit hyperactivity disorder; attenuated positive symptoms state; borderline personality disorder; brief intermittent psychotic symptoms state; dorsolateral prefrontal cortex; genetic risk with deterioration state; healthy controls; orbitofrontal cortex; regions of interest; subjects at ultra-high risk for psychosis; voxel-based morphometry.