“How does sleep affect mental health?” – something that I have no doubt has crossed your mind. Sleep and mental health, and similarly, sleep and stress, are closely related – which is exactly why lack of sleep leads to anxiety and depression. Today, I’m not going to share why sleep is important for mental health – but I will share how a lack of sleep affects your mental state, and as you’ll see, how in part, lack of sleep causes mental illness.
Why lack of sleep leaves you… stressed and anxious
Notice you can’t switch off after sleeping barely a wink? It’s not your imagination, it’s biochemistry.
Academic research has found that just one night of insufficient sleep can increase cortisol levels by 37 percent. After two nights, cortisol levels increase by 45 percent. As this is an awakening hormone, this can leave you feeling anxious, restless, nervous and unable to ‘switch off’.
Second to that, cortisol also makes you feel stressed throughout the night; cue difficulties in falling and staying asleep, and those dreaded 3am wake-ups.
Interestingly, this is particularly likely if you’re a Lion chronotype because you have a biological predisposition to be more anxious than those who prefer late nights.
How does sleep affect mental health – specifically depression?
Evidence indicates 83 percent of those with depression lack sufficient sleep.
The overarching link between lack of sleep and ‘feeling flat’ boils down to the HPA axis, a brain region controlling emotions: Research shows it becomes overactive.
Initially, this is felt as extra alertness and anxiety, however, prolonged overactivity of this region, the reverse happens: and you feel constantly flat.
Think about it. Towards the end of the year when you’re trying to run at 100 miles an hour, after a while, no amount of coffee or sugar seems to perk you up, right? That’s a sign of adrenal exhaustion, and stems from prolonged overactivity of the HPA axis.
In contrast to above, early risers – Lions – are at favour here, it’s night owls that need to be careful. Research shows the Wolf chronotype are 20 times more likely to suffer depression compared to those who wake early.
Why lack of sleep affects your mental health – overall
Emotions are controlled and stabilised by the frontal region. However, when sleep-deprived, this area of the brain is impaired, thus – your mood is up one day, down the next. Consequently, studies show you’re more likely to conflict with others. Second, you’re also more liekly to perceive a neutral situation as negative, and blow things out of proportion.
Overall, sleep and stress are closely intertwined – hence these problems. And as you may have suspected, sleep has become worse with COVID19.