DRD2 C957T genotype modulates the time-on-task effect during total sleep deprivation.

Total sleep deprivation (TSD) and time-on-task (TOT), especially in combination, increase cognitive instability and cause performance impairment. There are large inter-individual differences in TSD and TOT effects which, in part, have a genetic basis. Here, we show that the dopamine receptor D2 C957T genetic polymorphism predicts the magnitude of the TOT effect on a psychomotor vigilance test (PVT) during 38 h of TSD. This finding indicates that dopamine availability in the striatum, where the dopamine receptor D2 is most prevalent, influences the TOT effect, suggesting a role for dopaminergic pathways in sustained attention deficits during sleep loss.