Many of us aren’t strangers to how sleep loss slows down our physical reflexes and dulls our cognitive abilities. Think back to how you take longer to put on the brakes at a stoplight or process your colleague's conversation at work after a night of tossing and turning. But did you know that sleep deprivation impairs your mood, and by extension, your mental health way more than your motor and cognitive skills?
Sleep is the most under-considered, under-evaluated, and under-appreciated driver of mental health. But a growing body of scientific evidence is starting to change that perspective as it illuminates the two-way relationship between sleep and mental health.
Just like mental health problems make it harder to achieve a good night's sleep, poor sleep can also worsen your mental well-being. But there's a light at the end of the tunnel — better sleep can improve your mental wellness and keep psychological issues at bay.
For many, it seems like a chicken-and-egg situation: should you focus on improving your mental health to improve sleep? Or will you see bigger benefits the other way around? Ahead, we share what scientists and healthcare providers have to say about the impact of sleep on mental health and the best way to turn a no-win situation into a win-win.
Disclaimer: This post is not intended as medical advice. If you have any concerns regarding your sleep patterns or mental health, please speak to a licensed healthcare professional.
Whenever you look up symptoms of mental health disorders on Google, sleep problems almost always form part of the diagnosis. It could be something as mild as a lack of sleep to something as chronic as a sleep disorder. No wonder many of us believe mental health issues are the root cause of impaired sleep patterns!
While that narrative isn't wrong, it isn't wholly representative of the impact of sleep on mental health. In the past, healthcare providers and researchers believed that sleep disturbances were merely a hallmark and consequence of psychiatric disorders. Now, they have proof that sleep deprivation is the culprit, with circadian misalignment as the accomplice.
But, what exactly constitutes sleep deprivation? There are two stages:
Did you know that your sleep need is as genetically unique as your height or eye color? Instead of the generalized recommendation of eight hours of sleep per night, it's more likely your sleep need is between 7.5 and nine hours. And some people need even more than that to feel and function at their best the next day.
Not getting enough sleep extends beyond the increased grouchiness and negativity you feel upon waking. Below, we show how sleep deprivation affects your psychological health on the physiological, hormonal, and biochemical levels.
The prefrontal cortex (PFC) is the part of the brain located in the cerebrum that controls cognitive functions — say, creating an Excel spreadsheet to track sales or thinking of the best way to explain complex algebra equations to a high-schooler. Meanwhile, the amygdala regulates your emotions and memories and activates your fight-or-flight response when confronted with a threat.
So what's the relationship between the PFC and the amygdala relative to sleep? You can think of the PFC as the "parent" and the amygdala as the "child" that needs supervision.
When you get enough sleep, the PFC has no problem reining in the amygdala to prevent it from going haywire emotionally. But when you're sleep-deprived, the PFC shuts down and removes its inhibitory control over the amygdala.
In fact, research shows that just one night of sleep deprivation “triggers a 60% amplification in reactivity of the amygdala in response to emotionally negative pictures." This surge in anticipatory limbic activity sets the stage for anxiety-related mental illnesses, as you'll see later.
Sleep loss also upends the carefully calibrated cocktail of brain chemicals and hormones.
According to recent scientific evidence, sleep deprivation elevates the levels of serotonin 2A neurotransmitter receptors in as short as 6-8 hours. This abnormality is linked to hallucinations, cognitive impairment, and mental health conditions like schizophrenia.
Oxytocin, commonly known as the love hormone, isn't immune to sleep loss either. When you're well-rested, oxytocin dampens cortisol production and the resulting anxiety. It also represses amygdala hyperactivity to negative stimuli. At the same time, oxytocin boosts your ability to recognize emotions.
But there's a dark side to this love hormone, too. Scientists explain that while oxytocin lowers stress levels and enhances good vibes, a surge in it can elevate anxiety and fear. Given that sleep restriction hikes up oxytocin production, this may not bode well for your psychological wellness.
In fact, higher-than-normal oxytocin levels are present in adults with autism, schizophrenia, bipolar disorder, and generalized social anxiety. An oxytocin surge also correlates with symptoms of depression in children with obsessive compulsive disorder (OCD) and comorbid anxiety disorder.
Insidiously, sleep loss downgrades your mental health on a continual spectrum from commonplace stress to dangerous suicidal thoughts.
Because sleep exerts an inhibitory effect on cortisol production, not sleeping well means that the stress hormone now runs rampant in your body. The constant influx of cortisol circulating in your system aggravates your mental wellness and triggers stress-related symptoms.
To illustrate, a 2016 study involving adolescents found that more sleep problems predispose participants to increased cortisol reactivity to stress. In another study involving Chinese military soldiers, higher cortisol levels (courtesy of sleep deprivation) "positively correlated with the factor score of mania," spelling disaster for their mental health.
Sleep and anxiety are closely linked. For one, sleep disruption is a common symptom of anxiety disorders. At the same time, sleep deprivation can cause an increase in anxiety.
Most worryingly, just a single night of poor sleep inflates daytime anxiety levels on par with clinically diagnosed anxiety disorders in some individuals. Matthew Walker, one of the researchers of the 2019 study, highlighted that "sleep loss can causally and directionally instigate high levels of anxiety in individuals who were otherwise nonclinically anxious when sleep-rested.”
Many of us tend to be more irritable after a night of little to no sleep, making us less adept at handling minor stressors in everyday life.
A 2012 study published in the journal Emotion emulates this perfectly. Sleep-deprived participants exhibited more stress, anger, and anxiety than their well-rested counterparts during low-stress events. The study noted that "sleep deprivation lowers the psychological threshold for the perception of stress from cognitive demands."
Obviously, this has negative implications on your interpersonal relationships, and by extension, your quality of life. More than one study affirms that sleep insufficiency propagates romantic strife and makes it harder for partners to peacefully settle disagreements.
Various studies show that depression and sleep difficulties often go hand in hand. For starters, chronic insomnia enhances the risk of depression in affected individuals. Sleep-related breathing disorders, like obstructive sleep apnea, strongly correlate with depression, too. In the shift-work populace, long-term sleep loss and a disrupted circadian rhythm also trigger mood disorders and daytime sleepiness.
Interestingly, there's some research favoring short-term sleep deprivation as a "quick and efficient way to treat depression." It has a 60-70% success rate and works far better than antidepressants whose effects only kick in after several weeks. Of course, more research is needed. Most importantly, this treatment option should only be used under the guidance of a healthcare professional.
Since poor sleep is linked to various psychiatric disorders, such as depression and post-traumatic stress disorder (PTSD), it isn't that much of a stretch to say disturbed sleep is a breeding ground for suicidal thoughts.
Scientific evidence warns that insomnia may be a "clinical indicator of acute suicidal risk," especially in the presence of depression. On a related note, depressed people who struggle with short- or over-sleeping are more prone to having suicidal thoughts, too.
Most tellingly, a 2002 study found that even though depression has the strongest tie with suicide, poor sleep quality remains a prominent risk factor of suicide by a whopping 34%. Another 2015 study involving more than 15,000 middle-aged adults cautioned that difficulty maintaining sleep is a significant predictor of suicide 14 years later.
Another thing to keep in mind is that poor mental health is just as contagious as the common flu. Your bad mood may infect your family, friends, and co-workers, a phenomenon known as emotional contagion. The reason? In any social interaction, we copy others' facial expressions, tone of voice, and actions, whether consciously or not.
Perhaps you think that emotional contagion is only catching in person. But a 2014 study proved otherwise. Interacting on social networks like Facebook can also cause the spread of emotional contagion.
So far, we've talked about the impact of sleep on mental health. But your circadian rhythm, i.e., the internal body clock that regulates your sleep-wake cycle, also influences your psychological well-being.
Case in point: seasonal affective disorder (SAD), a seasonal form of depression that peaks with the onset of winter. Scientists think that the problem originates from circadian rhythm abnormalities in the form of a later-than-usual internal clock.
Later, we'll talk about how you can work with your circadian rhythm, alongside healthy sleep habits, to bolster your mental health.
Sure, sleep loss induces — and aggravates — mental health problems. But sleep itself is scientifically proven to improve various psychological parameters.
Per the earlier 2019 study, a full night of sleep (i.e., meeting your sleep need) significantly decreased anxiety levels. The improvements were even more profound for those who spent longer in slow-wave sleep. That's because deep sleep reboots the PFC, which in turn re-engages the amygdala to regulate your emotions.
When the researchers replicated the study design, the results showed the same finding: Those who had more deep sleep felt the least anxious the next day. As a result, Walker and his team are confident that "even modest improvements in sleep quality may have the potential to reduce subjective anxiety, serving as a non-pharmacological prophylactic."
Much of the current mental health care focuses on pharmacological and therapeutic interventions (such as antidepressants and meditation, respectively). But, improving your sleep may be the best thing you can do for your mental well-being. As Walker astutely notes, “The best bridge between despair and hope is a good night of sleep.”
And he is right, in all the ways that matter. Cutting down your sleep debt by eight hours tones down the negativity in your tone of voice by up to 67%, instantly making you sound more positive in your conversations with others. Similarly, paying down your sleep debt by eight hours leads to a 30% jump in your empathic response.
The proof keeps rolling in. A small study involving 15 young adults found that when they were allowed to sleep as much as they like, their alertness, reaction time, and mood greatly improved.
In that sense, getting enough sleep isn't just a talisman against "mental unhealth." Consistently meeting your sleep need every night supports your efforts in becoming the best version of yourself as a full-fledged emotionally intelligent and resilient individual.
So, should you improve sleep to boost your mental health or improve your mental health to benefit your sleep patterns? Research recommends the former as sleep shows a significantly bigger impact on psychological health than the other way around. Moreover, the benefits are immediately felt after just two recovery nights!
But you don't have to rely on sleep medicine to boost your sleep wellness. For the record, sleep supplements and aids don't promote naturalistic, healthy sleep, which is the manna for optimal mental health.
Instead, many sleep experts endorse cognitive behavioral therapy for insomnia (CBT-I) if you have difficulty falling asleep. CBT-I blends both psychological and behavioral interventions to offer a two-pronged approach to sleep and mental health problems. A 2017 commentary in The Lancet Psychiatry explained that CBT-I not only reduced comorbid insomnia but also improved various psychological symptoms, such as hallucinations, paranoia, anxiety, and depression.
Aside from therapeutic interventions (like CBT-I), good sleep hygiene is key. Sleep hygiene refers to the upkeep of behaviors that influence the way you sleep. You may be surprised to hear this, but many sleep hygiene practices actually take place during the day. But they are still included under the umbrella of sleep hygiene because of their effect on sleep.
Some key examples include:
Of course, the vast expanse of sleep hygiene covers more than just the above-mentioned tips. For the full story on how to hone your sleep hygiene to perfection, check out our step-by-step Sleep Guide.
Getting trapped in the vicious cycle of poor sleep and poorer mental health can take a toll on anyone. But the good news is, you can extricate yourself from said cycle and even enjoy the best of both worlds (read: healthy sleep for better mental wellbeing). It’s all contingent on how well you practice sleep hygiene every hour of the day.
Take note that optimal sleep hygiene only happens when it's tied to your circadian rhythm. Because everyone's internal clock is genetically unique, the best time for you to carry out your sleep-promoting activities may look different from others.
That's why we created RISE. Download the RISE app to automatically calculate your sleep need and attune your day to your circadian rhythm’s energy peaks and dips, which you can view on the Energy Schedule screen.
With 16 science-based habits that tell you the right times to do the right things, RISE helps you keep your sleep debt low, so you can be at your best mentally, emotionally, and physically. Talk about the best of both worlds!
RISE makes it easy to improve your sleep and daily energy to reach your potential
RISE makes it easy to improve your sleep and daily energy to reach your potential
