Waking up just an hour earlier can reduce the risk of major depression by 23%, according to a new comprehensive genetic study published in the journal May 26, 2021. Gamma Psychiatry.
The 840,000 study is by researchers at the University of Colorado Boulder and the Broad Institute With And Harvard University is one of the strongest pieces of evidence that chronotype – a person’s tendency to fall asleep at any time – influences depression risk.
It was also among the first studies to determine how much or little of the change needed to affect mental health.
When people work remotely and go to school after the pandemic – a trend that has led many Move to a later sleep scheduleThe results have important implications.
“We have known for some time that there is a relationship between bedtime and mood, but the question we often hear from doctors is: How far should we move people to see what benefits?” Lead author Celine Feter, assistant professor of integrative physiology at the University of Boulder, said. “We found that sleeping an hour before bed was associated with a significantly reduced risk of depression.”
Previous observational studies have shown that nocturnal people are twice as likely to have depression than those who wake up early, regardless of how long they sleep. But because mood disorders can disrupt sleep patterns, researchers have found it difficult to understand the cause.
Other studies had small samples and either relied on specific questionnaires or did not take into account environmental factors that could affect time and mood, and possibly distort the results.
In 2018, Vetter launched A great long-term study 32,000 nurses showed that early risers were up to 27% less likely to develop depression over a four-year period, but that raised the question: What does it mean to be early awake?
How do your genes affect when you wake up
To get a clearer sense of changing bedtime early, this is really protective and the amount of change required, lead author Iyas Douglas used data from DNA Company Test # 23 and Me and UK Biomedical Database. Douglas then used a method called “Mendelian randomization,” which uses genetic correlations to decode cause and effect.
“Our genes are determined at birth, so some preconceptions that influence other types of epidemiological research do not affect genetic studies,” said Douglas, who graduated from Harvard Medical School in May.
More than 340 common genotypes, including variants of the so-called “clock gene” PER2, It is known to influence a person’s chronotype, and genetics, together, explain 12-42% of our preferences during sleep.
The researchers evaluated non-specific genetic data on these variants of up to 850,000 people, including data from 85,000 people who used portable 7-day sleep trackers and 250,000 people who completed sleep preference questionnaires. This gave them a more detailed picture, yet, of how variants affect genes when we sleep and wake up.
In the largest of these samples, about a third of the individuals surveyed who identified themselves as morning birds, 9% were nocturnal owls and the rest in the middle. Generally, their average sleep was 3 AM, which means they went to bed at 11 PM and woke up at 6 AM.
With this information, the researchers switched to another sample, which contained genetic information, as well as prescription records, anonymous prescription records, and research on diagnosing major depression.
Using new statistical techniques, they wondered: Do those who have genetic variants that make them eligible for early awakening also have a lower risk of developing depression?
The answer is a firm yes.
Any point in the middle of bedtime an hour before (midway between bedtime and waking) corresponds to a 23% lower risk of major depression.
In other words, if a person usually goes to bed at 1 am, instead, goes to bed in the middle of the night and sleeps for the same amount of time, it could reduce that risk by 23%. If they go to bed at 11 PM, they can reduce it by about 40%.
The study does not indicate whether those who wake up early can benefit from waking up early. For those in the middle of the night or at night, it may be helpful to switch to an early bedtime.
Clear days, master dark nights
What could explain this effect?
Some research suggests that increased exposure during the day, which often occurs early in the morning, triggers a cascade of hormonal effects that can affect mood.
Others note that having a biological clock or a circadian rhythm that develops differently from most people can be frustrating in and of itself.
Douglas said, “We live in a society designed for people in the morning, and at night people often feel in a constant state of incompatibility with this social hour.”
He stresses that a large randomized controlled trial is needed to determine whether going to bed early can reduce depression. “But this study definitely shifts the weight of the evidence toward a causal effect of bedtime on depression.”
For those looking to switch to an early sleep schedule, Vetter offers this advice:
She says, “Make your days clear and your nights dark.” “Have your breakfast on the balcony. You can walk or bike to go to work when you can, and dim the electronics at night. “
Reference: “Preference for genetically determined day, bedtime and risk of major depressive disorder” Written by Iyas Douglas, BA; Jacqueline M. Lynn, PhD; Richa Saxena, PhD and Celine Vetter, PhD, May 26, 2021, Gamma Psychiatry.