CLOCK and mood disorder: Finally, genotype-mood disorder phenotype correlations have been made with core clock genes and melatonin synthesis pathway genes, including a variant of the ASMT gene promoter associated with poorer quality sleep, a TIMELESS variant associated with languid rhythms (i.e., sleep inertia) as well as a more vesperal profile and a RORA variant with less flexible profile of life rhythms [80,81,82].