Study: Women who are ‘early birds’ are less likely to develop depression

BOULDER, Colo. — Women who find themselves feeling blue may want to consider changing their bedtimes. A recent study found that middle-aged women who both go to bed and rise earlier are less likely to develop depression than others in the same demographic.

The study, conducted by researchers at the University of Colorado-Boulder and Brigham and Women’s Hospital in Boston, is among the first to associate chronotype, or the time of day a person typically sleeps, as a risk factor for mental health problems.

The researchers studied 32,000 depression-free female nurses, with an average age of 55, over four years to correlate sleep-wake tendencies with mood disorders. At the start of the study in 2009, 37 percent of participants described themselves as “early types,” 10 percent considered themselves “evening types,” and the rest described themselves as “intermediate types.”

After accounting for risk factors such as weight, exercise, work shifts, and sleep duration, they found that having an early to bed, early to rise sleep cycle mildly decreased the risk of developing depression in those studied by 12 to 27 percent. They also found women who were night owls were more likely to be unmarried, live alone, and smoke cigarettes.

“Our results show a modest link between chronotype and depression risk. This could be related to the overlap in genetic pathways associated with chronotype and mood,” says lead author Céline Vetter, director of the Circadian and Sleep Epidemiology Laboratory at Colorado University, Boulder, in a release.

Previous research showed increased risk of depression in night owls, but many of the studies that showed this also didn’t account for other risks of depression, and often took their findings at single time-points.

Vetter notes, however, that night owls shouldn’t necessarily expect to develop depression as chronotype only has a “small effect” on one’s risk. Still, for those who fear they could be headed down that path, she recommends working to become an early bird. One way to help accomplish this is to dim the lights in your home at night, and get as much natural light as you can during the day.

The study was published in the August 2018 edition of the Journal of Psychiatric Research.