Insomnia is often fuelled by anxiety. You can't sleep, so you feel anxious about being unable to sleep, which then keeps you awake even longer. It's a well understood cycle - but new scientific research into the correlation between lack of sleep and anxiety indicates just how much tiredness can open the floodgates to anxious thoughts. And it's a lot.
In a small study carried out by the the University of California, Berkley and published in the journal Nature Human Behaviour, researchers scanned the brains of 18 young adults. First, they assessed the participants as they were shown "emotionally stirring video clips" following a full night of sleep, and then again after a sleepless night. The study authors then measured anxiety levels using a questionnaire.
What was found was that a brain that's had a full night of deep sleep is more able to calm anxious thoughts, while a sleepless night can make a person 30% more anxious. Firm proof the world would be a terrible place if nobody ever slept.
The specific type of sleep that most stabilises an anxious mind, the researchers found, is non-rapid eye movement (NREM) slow-wave sleep. In the brain scans taking place after a night of no sleep, the participants' medial prefrontal cortexes were shown to be shut down. Ordinarily, this is the part of the brain that controls anxiety. Instead, the deeper emotional control rooms of the brain were shown to be overactive in the tired subjects.
While the study was only carried out on a small number of people who were all of a similar age - meaning far broader research would have to be conducted to make any totally conclusive findings - it does suggest that the best remedy for anxiety is good quality sleep. The study's senior author - Matthew Walker, a professor of neuroscience and psychology at Berkeley - described this kind of sleep as "a natural anxiolytic (anxiety inhibitor), so long as we get it each and every night".
Of course, the cruel trick of nature is that anxious thoughts can often prevent deep sleep, so continuing the cycle. But there are methods you can try to curb your anxiety and drift off; including meditating in the morning, ditching sleep trackers, and doing breathing tricks. Good luck!