The role of clock genes in the etiology of Major Depressive Disorder

Background: Circadian rhythms are largely dysregulated in Major Depressive Disorder (MDD). The present review provides a summary of the findings about the role of clock genes in the etiology of MDD. Methods: A careful search of articles on Pubmed, PsycINFO, Isi Web of Knowledge was performed in order to obtain a comprehensive review about the topic. Results: The studies reported contrasting results about the association of different single nucleotide polymorphisms (SNPs) in clock genes and MDD. The most consistent result reported the association between SNP rs2287161 of CRY1 and MDD development. Limitations: Most of the published papers on the topic show bias as a prevalence of Asian ethnicity or not blinded conditions of laboratory experiments with respect to subjects' conditions (healthy controls or MDD). Conclusion: Further epigenetic and genome-wide studies are necessary to have a more clear idea about the role of clock genes in the etiology of MDD.