Most people notice that if they haven’t had enough sleep, they are more irritable or feel low. Many studies have supported this with evidence that adequate sleep is associated with a better mood and more resilience to stress. What exactly does sleep do for our mental health?
During the night we have different types of sleep: rapid eye movement (REM) sleep and non-rapid eye movement (NREM) sleep. NREM sleep is divided into three stages: stages one and two are light sleep and stage three is deep sleep.
During sleep the brain is very active. And what is going on depends on the stage of sleep you are in.
During light sleep, after a transition for wakefulness, experiences from the day are processed and consolidated into memory.
During deep sleep the immune system is boosted as the body repairs and replenishes itself and clears out toxins from the brain. Deep sleep is also involved in the regulation of metabolism, hormone release and memory.
REM sleep is most closely linked to mental health. This is when you do the bulk of your dreaming and it’s important for emotion regulation, learning and memory processing. Emotional experiences are reprocessed and consolidated into memory networks. Sleep deprivation or sleep disturbance affects your ability to consolidate positive emotional content.
With many mental health conditions, changes are seen with the amount of REM increasing or decreasing or the timing of REM onset changing.
It’s a common experience to struggle to sleep if you are worrying about something. Worrying triggers the fight or flight response as the brain, mistakenly, prepares for danger. If your brain thinks you are in danger, your need for sleep is reduced as you must stay awake and be alert to protect yourself.
When you are in flight or fight mode, the sympathetic nervous system is in charge, leading to increased heart rate, shallow breathing, tense muscles and other bodily changes which make it very hard for you to sleep. To get to sleep you need the parasympathetic nervous system to be triggered, this leads to the relaxation response in the body, the mode you want to be in to sleep. You can encourage this with deep breathing from the belly or other relaxation exercises.
If you are going through something difficult or stressful, having problems sleeping is entirely normal and not something to worry about. Your body is in fact doing what it is supposed to do; reducing the amount you sleep to keep you safe from perceived danger.
Sleep is strongly associated with a number of mental health conditions. Around 70-90% of people with depression and anxiety disorders also struggle to sleep but hypersomnia, or sleeping too much, is also common in depression. Traditionally, sleep problems have been seen as a symptom of mental health problems. However, this view has been questioned with more recent evidence indicating that sleep and mental health have a bidirectional relationship: sleep can cause mental health problems but may also be a consequence of these problems, and this leads to a vicious cycle where one problem is reinforced by the other.
This makes intuitive sense. If you are feeling anxious or upset by something you probably will struggle to sleep. If you have a disturbed night of sleep, you are likely to feel more anxious or low the next day, leading to another night of poor sleep. On top of this, you may start worrying about not sleeping which then makes it harder to sleep, worsening your mood.
Studies have shown that sleep problems often appear before mental health problems start. Research shows that treating sleep issues can significantly improve mental health conditions while poor sleep is associated with poor treatment response for these conditions. When sleep problems remain after successful treatment of mental health problems, this often increases the likelihood of relapse.
Sleep is now thought to play a causal role in the development and maintenance of mental health issues. Therefore, treating insomnia can not only improve mental health conditions but may also prevent them developing and reduce the risk of relapse. However, separate treatment may be needed for mental health issues; we can’t assume that treating one problem will absolutely solve the other. But we can conclude that treating only the mental health condition and ignoring sleep problems is not a solution.
Christabel Majendie August 2022.
Christabel is a Bristol based sleep therapist and consultant, specialising in helping individuals experiencing a wide range of sleep problems. For more information on her work you can visit her website.
Christabel Majendie is not a brand ambassador and does not endorse any product of Sleep Well Drinks Limited.