Fig. 3.

Left panel shows that an initially hyper-responsive VS-system might increase the probability to behave impulsively in multiple ways (positive correlation in the healthy population). In some individuals, putatively those with additional (genetic) risk factors, such repeated VS-overstimulation triggered by impulsive behaviour might lead to a subsequent down-regulation of the reward system (middle panel). The degree of down-regulation is presumably positively correlated with the degree of impulsivity and therefore a negative correlation of symptom severity and VS-response results (right panel).