PER3 and Anxiety: Interestingly, the anxiety risk associated with the co-occurrence of CRY1_GG with PER3-A_GG in females is similar in magnitude to the male-specific association for CRY1_CC/ PER3-A_GG genotypes, suggesting that CRY1 homozygotes, in the presence of PER3-A_GG, may affect anxiety via distinct sex-specific mechanisms.