In a major finding published in the journal JAMA Psychiatry, scientists report that one’s sleep schedule can influence risk of depression. Your sleep schedule is largely determined by your chronotype—your circadian rhythm, which is your internal clock. This can determine your propensity to be high energy or sleepy at certain times of the day. Researchers found that people predisposed by genetics to be early risers firmly have a lower risk of depression.

The study

Genetics can explain up to 42 percent of our sleep timing patterns. Researchers from the University of Colorado Boulder and the Broad Institute of MIT and Harvard explored depression risk based on chronotype. They obtained sleep data using DNA testing brand 23andMe as well as biomedical database UK Biobank.

With data from up to 850,000 individuals, the researchers categorized subjects into three groups: Morning larks, night owls and those in-between. They then analyzed this information in relation to genetic data, plus medical and prescription records and diagnoses of major depressive disorder.