Analysis of single SNPs in males (n = 687) yielded suggestive evidence for association (P<0.05) between depression and depression accompanied by signs of disturbed sleep with 14 SNPs from six genes: ARNTL, aryl hydrocarbon receptor nuclear translocator-like 2 (ARNTL2), RORA, NPAS2, TIPIN and period homolog 1 (Drosophila) (PER1) (Table 2; full data available in Table S2). Here, PER1 is linked to major depressive disorder.