“Healthy sleep is a necessity for physical, mental, and emotional well-being,” said American Academy of Sleep Medicine President Dr. M. Safwan Badr. “This new research emphasizes that we can make an investment in our health by prioritizing sleep.”
The first study of 1,788 adult twins discovered a gene by environment interaction between self-reported sleep duration and depressive symptoms.
According to researchers, the findings suggest that those who sleep shorter — or longer — than the normal eight or so hours a night increased the genetic risk for depressive symptoms.
Among twins with a normal sleep duration of 7 to 8.9 hours per night, the total heritability of depressive symptoms was 27 percent, according to the researchers. The genetic influence increased to 53 percent among twins with a shorter sleep duration of just five hours a night and 49 percent among those who reported sleeping 10 hours a night.
“We were surprised that the heritability of depressive symptoms in twins with very short sleep was nearly twice the heritability in twins sleeping normal amounts of time,” said principal investigator Nathaniel Watson, M.D., associate professor of neurology and co-director of the University of Washington Medicine Sleep Center in Seattle. “Both short and excessively long sleep durations appear to activate genes related to depressive symptoms.”
“The study’s findings suggest that optimizing sleep may be one way to maximize the effectiveness of treatments for depression, such as psychotherapy,” he said.
Another study of 4,175 children between the ages of 11 and 17 found that sleeping six hours or less a night increases the risk for major depression, which in turn increases the risk for decreased sleep among adolescents.
“These results are important because they suggest that sleep deprivation may be a precursor for major depression in adolescents, occurring before other symptoms of major depression and additional mood disorders,” said principal investigator Robert E. Roberts, Ph.D., professor of behavioral sciences in the School of Public Health at the University of Texas Health Science Center in Houston, Texas.
“Questions on sleep disturbance and hours of sleep should be part of the medical history of adolescents to ascertain risk.”