PER2 and Anxiety: We also found that PER2-GG was strongly associated with an increase in anxiety scores (coefficient = 2.17, t418 = 2.09, p = 0.038) and the combination of PER3B-AG and CRY2-AG was weakly associated with anxiety scores (coefficient = 4.44, t418 = 1.85, p = 0.065); interestingly, these effects were completely mediated by diurnal preference score.