
A sweeping study from numerous notable universities found that waking just one hour earlier can cut your risk of major depression by 23%.
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.
Genetics can explain up to 42% 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.
An analysis of the data reported that people with a chronotype supporting earlier sleep and wake times corresponded with lower risk of depression.
For every one-hour earlier sleep midpoint – meaning, the time halfway between bedtime and wake time – subjects had a 23% lower risk of major depressive disorder. The earlier people went to bed, the better they tended to feel.
Say for example, you normally go to bed at 1am, sleep nine hours and wake at 10am. You then move your schedule up one hour, now going to bed at midnight, still sleeping for nine hours and waking at 9am. You may be able to cut your risk of depression by 23%. If you went to bed yet another hour earlier, you could cut risk of depression again by roughly another 23%.
While the study finds that people with earlier sleep-and-wake schedules had lower risk of depression, it doesn’t conclusively determine exactly why. But the researchers have several theories:
This novel study is among the first to clearly quantify how much change is required to affect your mental health. It found that shifting your sleep-and-wake clock by just one hour can decrease depression significantly. It also found that shifting by multiple hours had a cumulative effect on the quantity of improvement.
Ask yourself if you are experiencing a social dissonance in terms of the internal clock you feel compelled to live by. Do you find that you sleep and wake at a different time from most people around you? Does your inner clock not correspond with the hours demanded by your responsibilities, like your workplace or school? This may be because you have a night owl’s chronotype.
But can you permanently change your sleep cycle if you are genetically predisposed to a certain schedule? Our chronotypes are largely determined by our genetics, and therefore it can be hard to make a major change that goes against what is natural for our bodies. However, this shift need not be dramatic. As demonstrated by the study, just a one-hour change may notably decrease risk of depression. You only have to shift your sleep schedule 1-2 hours earlier than your norm to experience improvement.
The more you know about sleep, the easier it is to gain control over your cycle. For more sleep-related reads from Clean Eating, check out the following insightful articles: