The research: University of Washington Medicine Sleep Center researchers conducted the study on nearly 1,800 adult twins to observe how sleep duration affects the heritability of depressive symptoms. Among twins sleeping what researchers deemed the “normal” amount—7 to 9 hours—their total genetic risk for depressive symptoms was 27%, but increased to 53% among twins who reported sleeping 5 hours per night, and 49% for those who slept 10 hours. What it means: “This is just another thing pointing to the importance of getting a normal amount of sleep,” says study author Nathanial F. Watson, MD, MS, director of the sleep center and a board member at the Academy of Sleep Medicine. The study doesn’t show that sleeping too much or too little will give you depression, but rather that poor sleep habits “emphasize the genetic component of what is dictating mood in a depressive direction,” he explains. It’s not all that surprising as insomnia is a defining symptom of depression, and depression sufferers commonly report trouble sleeping. “We think the findings suggest that treatments for depression may be most beneficial in patients that are sleeping normal amounts of time.” The bottom line: “The body craves a rhythmic life,” says Dr. Watson. And without that rhythm, you’re more predisposed for conditions like diabetes, obesity, hypertension, cardiovascular disease—and now, an increased genetic rick for depressive symptoms. More from Prevention: What A Lack Of Sleep Does To Your Body
