This is important, as a new study published in JAMA Psychiatry suggests people who start their days earlier are less likely to develop depression. Previous research has shown a correlation between sleep and mental health. For example, night owls are more likely to suffer from depression, regardless of how long they sleep. But this study is one of the first to quantify the amount of sleep that can improve mental health.
The Research
The study looked specifically at genetics in relation to sleep schedules. Using biomedical database UK Biobank and DNA-testing company 23andMe, researchers analyzed data from nearly 840,000 individuals. Of this sample, 250,000 individuals had filled out sleep preference questionnaires, and 85,000 had worn wearable sleep trackers for a week. This painted a clearer picture of how gene variants influenced sleep and wake times. This also gave researchers access to data on medical and prescription records, as well as surveys about major depressive disorder. With all of this information, they could easily see the times that people went to sleep, when they rose, the midpoints of their sleep and their diagnoses for depression. The analysis showed that individuals who are predisposed to be early risers had a lower risk of depression, and that shifting your sleep schedule by even one hour earlier can decrease that risk by 23%. “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?” said senior study author Céline Vetter, PhD, in a statement. “We found that one-hour earlier sleep timing is associated with significantly lower risk of depression.” David Rapoport, MD, director of the sleep medicine research program at Icahn School of Medicine at Mount Sinai and advisor to sleep fitness company Eight Sleep, says the study clearly establishes the possibility of a relationship, but that there are also limitations. “Its strongest contribution is to confirm or to strengthen the association with the genetics,” Rapoport says. “You were born with something which predicts both early chronotype and, perhaps, protection from depression.”
Sleep Hygiene and Depression
Rapoport’s research focuses mainly on conditions like sleep apnea, which is associated with depressive symptoms. He notes that humans are very good at surviving on little sleep, but that sleep deprivation eventually takes a toll on the mind and body. “Bad sleep habits—meaning not getting enough, primarily—has an impact on fostering depression,” Rapoport says. “There is now a growing body of evidence that at least for insomnia and possibly depression, treating the sleep behavior and lack of sleep hygiene as a primary thing has some benefits.” This, of course, does not apply to severe mental illness, Rapoport notes. It’s important to note that being genetically predisposed to start your day early differs from waking up with the help of an alarm. Because researchers lacked access to data on whether participants woke up naturally versus waking up to go to work or other obligations, further research is required to determine definitive causation between sleep schedule and depression. A large-scale randomized clinical trial could provide a stronger link. If you’d like to shift your sleep pattern, it’s important to pay attention to the amount of daylight and screen time you’re getting. To consistently get an earlier start, begin your day with bright sunlight and stop using phones and laptops around 10 p.m. This aids your circadian rhythm. Taking supplements like melatonin or other sleeping pills can also help, but be sure to consult with a doctor first. The key then becomes sticking to your new schedule, as it could take several weeks to a month to adjust. Patience is necessary, as well as the understanding that your chronotype is part of your wiring, and changing it is, in a sense, fighting nature. “While we can fight it and force it, it could always spontaneously relapse,” Rapoport says.
