Morning People May Be at Lower Risk of Depression Than Night Owls - The New York Times

Going to bed early and waking up early may help to provide some protection against depression, a new study suggests.

Several studies of the body’s circadian sleep-wake cycle have shown that being an early bird is associated with a lower risk for depression.

With Mendelian randomization, researchers can compare large groups of people based on genetic variants that are independent of other health or behavioral characteristics — in this case, the tendency to being a night owl or a morning person, inherited traits that are randomly allocated during our development in the womb.

For the study, the scientists used two genetic databases of more than 800,000 adults to do a Mendelian randomization study of circadian rhythm and the risk for depression.

They found that in people with the genetic variants for being an early bird, for every hour earlier the sleep midpoint, there was a 23 percent lower risk of major depression.