of the central circadian rhythm organization system in the suprachiasmatic nucleus (SCN). PER1 has recently been shown to be associated with alcohol use, indicating that variation in PER1 gene mediated stress-induced drinking in animals and humans [41]. Molecular experiments in human Per1 gene demonstrated a genotype specific increase in the transcription of Per1 according to the concentration of glucocorticoids. This may point to a gene-stress interaction effect on the transcription of Per1, possibly resulting in different circadian organization under stressful conditions, which in turn may lead to self-medication with alcohol in those individuals.
