A recent study summarising the best available evidence, found that improving sleep quality led to improvements in depression, anxiety, rumination, and stress. Another example of the power of sleep over our health.

Our mental health – just like our physical health – is largely determined by our daily eat, move, and sleep habits. While they’re all equally important, sleep is perhaps the one most obviously linked to mental health.

A few weeks ago, I wrote about the profound impact of sleep on cognitive performance. Today, we’re going to look at the (equally profound) effect of sleep on other aspects of mental health.

You know what it’s like when you haven’t slept well. You’re more irritable, moody, and reactive. And that’s because sleep is the state in which the brain and mind recover, reset, and rewire. If you don’t get enough sleep, your mental state is not prepared for the challenges of the day to come.

At the end of last year, a meta-analysis of randomised controlled trials (the pinnacle of the evidence hierarchy) found that improving sleep quality led to improvements in overall mental health and specific mental health difficulties including depression, anxiety, rumination, and stress.

But perhaps most importantly, there was a dose-response relationship between sleep quality and mental health. In other words, greater improvements in sleep quality led to greater improvements in mental health.

It didn’t appear to matter what methods were used to improve sleep quality. Most of the included trials used cognitive behaviour therapy (CBT), but the non-CBT interventions (which included acupuncture, pharmacological treatments, sleep hygiene, sleep restriction, Tai Chi, herbal remedies, walking, and yoga) were equally as effective. It’s worth noting that, to isolate the effect of sleep quality on mental health, CBT methods that specifically targeted a mental health problem were excluded.

What is sleep quality? I’ll let the study authors explain: “Sleep quality consists of sleep continuity (e.g., sleep onset, sleep maintenance, and number of awakenings) and daytime impact (e.g., the extent to which the person feels refreshed on waking and throughout the day).”

There are many simple daily habits that can help improve sleep quality. I’ve written about some of these before:

• Get more outdoor light in the morning and throughout the day
• Wear blue-light blocking glasses in the evening
• Turn your phone off – or put it out of sight/reach – in the evening

So, there it is. More evidence that better sleep is one of the foundations of good mental health.

Most organisations I speak to say they are concerned about the mental health of their employees. Many are taking action to help their people improve their mental health. Very few are focussing on sleep.

I hope we can change that.