Molecular regulation of circadian rhythm and psychiatric disorders: a systematic review

ABSTRACT Objective The article aims to investigate the clock genes that are most associated with psychiatric disorders, the functions, and locations of these genes, as well as to investigate the main disorder, method and model in the analyzes. The paper seeks to summarize the findings and discuss the impact of this research on scientific knowledge. Methods This review used a systematic methodology (Prospero; ID 152031) and followed the PRISMA guidelines. The studies were searched in the PubMed/MEDLINE and Scientific Electronic Library Online databases and the terms of the Medical Subject Headings Terms were used. Quantitative studies with conclusive results regarding the association of psychiatric disorders with the molecular regulation of circadian rhythm were selected. The useful information was extracted and used for the elaboration of graphs and tables. Results We included 24 articles in our study. Bipolar disorder was the most commonly addressed psychiatric disorder (40% of studies); The participants’ Polish nationality also stood out in 39% of the works. Additionally, the PER gene was the most studied (25%) and the cerebral cortex was the main region in which the evaluated clock genes express themselves (34%). Finally, common PCR was the most used method (38%) and serotonin metabolism was the main function performed by gene products (16%). Conclusions Taken together, the results suggest that bipolar disorder is the most prevalent psychiatric disorder among research related to circadian genes, expressed mainly in the cerebral cortex of humans, especially the PER gene.