Am J Psychiatry 168 :10 , O ctober 2011 ajp.psychiatryonline.o rg 1 0 9 9 (5), as evidenced by steeper temporal discounting rates, altered decision making, and an aversion to delay of gratification in reward-related tests (6–9). Temporal discounting is the patient’s preference to receive smaller rewards sooner rather than larger rewards later and is postulated to be an intermediate phenotype for impulsivity. Neuroimaging studies have shown engagement of alternative brain regions in decision making in ADHD patients (10). A prominent feature is hypoactivation of the ventral striatum, a brain area with an important role in reward processing (11, 12), during reward anticipation (13, 14). Ventral striatal activity is also associated with impulsivity, a hallmark of ADHD (12, 13). Recently, the NOS1 gene was identified as a candidate gene for ADHD and other impulsivity disorders (15). A variant in this gene was also among the top findings of a genome-wide association study in ADHD (3). NOS1 encodes nitric oxide synthase 1. Nitric oxide, the product of this enzyme’s activity, acts as the second messenger downstream of the N-methyl-d-aspartate receptor and interacts with both the dopaminergic and serotonergic systems in the human brain. Nitric oxide inhibits monoamine transporters, thereby modulating the dopamine and noradrenalin concentration in the extracellular space (16). In addi(Am J P sych ia try 2 011 ; 1 68 :1099–1106 ) N itric O x ide Syn thase G eno type M odu la tion o f Im pu lsiv ity and Ven tra l S tria ta l A c tiv ity in A du lt A DHD Pa tien ts and H ea lthy Com parison Sub je c ts

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@inproceedings{Hoogman2011GeNOtyPeEI, title={GeNOtyPe effeCtS IN A}, author={Martine Hoogman and Dorine I. E. Slaats-Willemse and Marlies A M Naber}, year={2011} }