Assessing relationships among impulsive sensation-seeking, reward circuitry activity, and risk for psychopathology: a functional magnetic resonance imaging replication and extension study

Abstract (249 of 250 words) Background High trait impulsive sensation seeking (ISS), the tendency to engage in behavior without forethought and to seek out new/extreme experiences, is a transdiagnostic risk factor for externalizing and mood disorders, particularly bipolar disorder (BD). We published a positive association between trait ISS and reward expectancy-related activity in the left ventrolateral prefrontal cortex (L vlPFC) and ventral striatum (VS). We aimed to replicate this finding and extend it by testing for mediation effects of ISS on relationships between reward expectancy-related activity and measures denoting hypomania. Methods A transdiagnostic sample of 127 adults aged 18-25 completed a card-based guessing fMRI task as well as measures of ISS (inattention, motor impulsivity, fun seeking, positive and negative urgency) and the Moods Spectrum (MOODS) as a measure of hypomania. A sample of 98 from the original Chase et al. (2017) study was included for confirmatory and mediation analyses. Results We replicated a positive relationship between reward expectancy-related L vlPFC activity and negative urgency, an ISS component (β=0.28,t=2.44,p=0.0169). We combined these data with the original paper sample, confirming this finding (β=0.27,t=2.41,p=0.0184). Negative urgency statistically mediated the relationship between reward expectancy-related L vlPFC activity and MOODS factors associated with hypomania. No other associations between ISS measures and reward-expectancy related activity were replicated. Conclusions We replicated findings showing that reward expectancy-related L vlPFC activity is a biomarker for negative urgency, the tendency to react with frustration during distressing conditions. Negative urgency also statistically mediated the relationship between L vlPFC activity and measures indicative of hypomanic symptoms.