A new genetic study published in the journal JAMA Psychiatry suggests waking up just an hour earlier could reduce a person's risk of major depression by 23 per cent. Researchers at the University of Colorado Boulder and the Broad Institute of MIT and Harvard conducted the study of 840,000 people representing some of the strongest evidence yet that chronotype influences depression risk. Chronotype means a person's propensity to sleep at a certain time.
The study is also among the first to quantify just how much, or little change is required to influence mental health. Senior author Celine Vetter, assistant professor of integrative physiology at CU Boulder said, “We have known for some time that there is a relationship between sleep timing and mood, but a question we often hear from clinicians is: How much earlier do we need to shift people to see a benefit? We found that even one-hour earlier sleep timing is associated with significantly lower risk of depression.”
Lead author Iyas Daghlas, M.D., used data from DNA testing company 23 and Me to get a clearer sense of whether shifting sleep time earlier is truly helpful, and if so, how much shift is required. Daghlas then used the Mendelian randomization method that leverages genetic associations to help decipher cause and effect. Daghlas said, “Our genetics are set at birth so some of the biases that affect other kinds of epidemiological research tend not to affect genetic studies.”