People who are genetically programmed to be early risers have a lower risk of schizophrenia and depression, according to a new study.
Researchers from the University of Exeter and Massachusetts General Hospital linked the circadian rhythm, otherwise known as a person's body clock, to mental health, saying that those who are morning people are more likely to have greater well-being than night owls.
The study was published in the journal Nature Communications on Tuesday, Jan. 29.
Early To Bed, Early To Rise
The study used data from 250,000 participants in the United States via 23andMe, a private company that provides gene analysis, and 450,000 from the United Kingdom Biobank. Each participant was asked whether they are a morning or an evening person. The researchers looked at their genome to see a pattern and identify which genes they had in common that might affect their body clock.
The information was verified through monitoring wrist-worn activity trackers of participants based in the United Kingdom.
The team identified 351 genes that influence whether a person wakes up early or late. These genes, they found, not only central to the circadian rhythm. They are also expressed in the brain and in the retinal tissue of the eye, which might explain how the brain knows when to reset the body clock.
The study also revealed genetic variants that can shift a person's wake-up time by up to 25 minutes. However, they could not say whether the genes affect the quality of sleep.
Sleep And Mental Health
"Our work indicates that part of the reason why some people are up with the lark while others are night owls is because of differences in both the way our brains react to external light signals and the normal functioning of our internal clocks," said Samuel E. Jones, the lead author of the study. "These small differences may have potentially significant effects on the ability of our body clocks to keep time effectively, potentially altering risk of both disease and mental health disorders."
Jacqueline M. Lane, a co-lead author of the study, hopes that their findings could contribute to the current understanding of the link between mental health and sleep and, therefore, develop new treatments for patients with more extreme conditions.
The researchers noted that more studies are needed to fully explore the link between sleep and mental health.