(74), and have similar maturational trends. Younger adults tend to be more evening type and antagonistic, and older people are more agreeable (75) and more likely to be “morning types” (76). Mixed findings have been reported for a CLOCK variant known as 3111 T/C (rs1801260) with numerous traits and disorders, including morningness-eveningness preferences (77), sleep and mood disorders (78, 79), schizophrenia (80), and lower body weight among individuals with eating disorders (81). The 3111 T/C variant is weakly linked to rs6832769 (r2 = 0.212; physical distance = 3,175bp). To relate our finding to previous studies we used a hidden Markov program (11) to impute results for the 3111 T/C SNP. The imputed genotype was significantly associated with Agreeableness (rs1801260, P = .0067, effect = .08), with the T allele associated with higher Agreeableness scores. This is consistent with the findings of the T allele associated with morning preference and lower risk of mental disorders found in previous studies (77-81).
