Most people understand sleep or lack of sleep can affect our mood and functioning. But we tend to think of it in a temporary, somewhat superficial way: We’re grumpy if we don’t get enough sleep one night, but figure we’ll be fine if we catch up on sleep later.
That’s not really how it works. Research shows the connection is much deeper than that. This is also evidenced by the power of sleep interventions, which can actually mitigate depression, PTSD, and improve people’s quality of life.
A study published Tuesday in PLOS Medicine takes this understanding further, revealing a strong connection between sleep and mental health. These findings have significant implications for how we diagnose, treat, and even prevent mood and anxiety disorders.
Lead author Michael Wainberg is a postdoctoral fellow at the University of Toronto. He tells Inverse this study is especially unique because of the number of people evaluated — nearly 100,000 — and how the study team gathered data. They used “wrist-worn accelerometers to quantify sleep rather than relying on self-reporting,” Wainberg explains.
This is notable because much of what researchers know about sleep and mental health is based on self-reporting, Wainberg says. But self-reported measures of sleep don’t always reflect the actual sleep a person gets.
“Past studies have shown that people are surprisingly bad at estimating their true sleep duration — the average person may be as much as 75 minutes off,” Wainberg says. “People with depression may be especially inaccurate at reporting how well or how long they slept.”
While a number of studies have examined why good sleep is necessary for good mental health, this paper examined how poor mental health can influence overall sleep. Ultimately, the study team found sleep quality was more affected by psychiatric diagnosis than the number of hours slept.
This suggests people who are diagnosed with a mental health disorder are more likely to have poor sleep compared to the general population, reports the study team. Critically, Wainberg and sleep specialist Whitney Roban tell Inverse there are actionable steps individuals undergoing mental health hurdles can take to improve sleep quality.
How the discovery was made — In order to accurately measure sleep, Wainberg and colleagues gave 89,205 participants accelerometers (sleep trackers) to wear for seven days between 2013 and 2015. The accelerometers measured sleep timing, duration, variability, and efficiency.
The researchers had data about any psychiatric diagnoses the participants had, most significantly bipolar disorder, major depressive disorder, anxiety disorders, and schizophrenia spectrum disorders.
They also had data about other health conditions the participants may have had, as well as sociodemographic information. The study participant group was 56 percent female and they ranged in age from 43 to 79.
What they found— Across ages, genders, and socioeconomic factors, participants who had ever been diagnosed with depression, anxiety, bipolar, or schizophrenia experienced change — usually for the worse —in their sleep patterns.
“I was most surprised by the consistency of the results across sleep parameters and across diagnoses.”
This held true across nearly every sleep parameter the researchers measured, including bedtime, wake-up time, sleep duration, number of nighttime awakenings.
The effect was relatively small but very consistent. The largest effect was between sleep efficiency and major depressive disorder — people with depression had the least efficient sleep.
“Personally, I was most surprised by the consistency of the results across sleep parameters and across diagnoses,” Wainberg says. “We were also surprised by how — even in people with a diagnosis of a mental illness even a decade or more prior to when their sleep was assessed — there was still evidence of disrupted sleep in these individuals.”
7 sleep tips that can help with mental health
Given these findings, Inverse asked Wainberg and Roban, a sleep specialist and author, about how people facing mental health challenges can get better sleep.
“During times of great stress when mental health issues are at their highest, it is easy to revert to daily habits that are not conducive to healthy sleep,” Roban tells Inverse, “such as unhealthy eating, decreased physical activity, increase in alcohol consumption, inappropriate sleep schedules, and consistent worrying.”
Roban has five main tips for how people struggling with their mental health can improve their sleep:
1. Follow a consistent sleep schedule, going to bed and waking up approximately the same time each day. Our bodies thrive on consistency, and a consistent sleep schedule promotes healthy sleep.
2. Follow a brief and consistent bedtime routine every night. Do something that relaxes you (yoga stretches, deep breathing, journaling, reading a non-digital book, listening to relaxing music) every night before bed. A consistent bedtime routine will signal to the brain and body that it is time for sleep.
3. Turn off all electronics at least one hour before bed and charge them outside of your bedroom. If you must use electronics before bed due, use blue light blocking glasses or get a blue light blocking screen for your computer.
4. No caffeine after lunch, and no heavy meals and alcohol close to bedtime. Try to avoid fatty and spicy food before bed as well.
5. Recognize and accept the importance of sleep in your life. Once you prioritize sleep, it will be easier to make the daily behavioral changes and commitment that will lead to healthy sleep and better mental health.
Wainberg adds that getting treatment for the underlying mental health issue is vitally important.
Since sleep trackers can give such precise information about sleep, Wainberg says personal sleep trackers, like a Fitbit or Apple Watch, “can also play a role here since they can help reveal which lifestyle factors might contribute to better or worse sleep.”
What’s next — Wainberg and colleagues have already started building on the results of their study.
“We're currently working with collaborators at our institute who are looking at the genetics of our sleep parameters among people with depression,” Wainberg says. The center he works with, the Krembil Centre for Neuroinformatics, is currently developing a patient data biobank.
Ultimately, Wainberg says, “the core goal of the CAMH BrainHealth Databank is to use patient data, including the use of wearables outside of a hospital setting, to deliver improved, personalized mental health care in the present — while also accelerating future clinical research, discovery, and innovation.”
Background: Sleep problems are both symptoms of and modifiable risk factors for many psychiatric disorders. Wrist-worn accelerometers enable objective measurement of sleep at scale. Here, we aimed to examine the association of accelerometer-derived sleep measures with psychiatric diagnoses and polygenic risk scores in a large community-based cohort.
Conclusions: In this study, we observed that sleep pattern differences are a transdiagnostic feature of individuals with lifetime mental illness, suggesting that they should be considered regardless of diagnosis. Accelerometry provides a scalable way to objectively measure sleep properties in psychiatric clinical research and practice, even across tens of thousands of individuals.