How Sleep Regulates Your Emotional Memories and Mental Health

Intrusive emotional thoughts linked to lack of sleep

Getting a good night of sleep is a challenging endeavour these days. In light of political unrest and a worldwide pandemic in addition to existential dread, it is no surprise that we sometimes find ourselves up at 3:00 am, refreshing our Twitter feeds or worrying about family. Many of us even returned to work in some capacity. While receiving around 7–8 hours of sleep is recommended, it is sometimes difficult to prioritize. It is an infinite feedback loop causing exhaustion and poor mental health.

Often, those of us with depression or post-traumatic stress disorder ruminate on these intrusive thoughts. Throughout the day, something within your environment may remind you of a memory. There is a switch in the brain that decides whether to pursue or ignore this recall cue. Often when there is a lack of inhibitory control, these stimuli evoke negative emotional memories, repetitive irrational thoughts about your self-worth, and even thoughts about self-harm. The parts of our brain involved in processing complex thoughts, critical thinking, memory, and emotion are all involved in this maladaptive circuit.

At the root of this problem is the inability of the brain to regulate these thoughts. Sleep disturbances are common among many psychiatric disorders. Understanding the relationship between the regulation of these thoughts and sleep will help us in our quest to conquer depression and post-traumatic stress. Plus who wouldn’t want a prescription for sleep?

While plenty of scientists study the reasons we sleep, there isn’t one single answer. Nonetheless, sleep or sleep-like states exist in many different animals, indicating its importance for survival. Researchers from the Department of Psychology at the University of York found a surprising link between lack of sleep and obtrusive thoughts, published in Clinical Psychological Science.

Sixty volunteers participated in this experiment. Experimenters showed them pictures of faces, teaching them to associate some faces with neutral photos and others with more negative scenes (the difference between an image of a street and one of a war zone). Then, half of these participants slept while the other half experienced sleep deprivation. The next day, experimenters showed these faces to participants, asking them to actively suppress their thoughts, memories or emotions of the associated images. The sleep-deprived participants experienced more difficulty in blocking these negative thoughts.

The senior author Dr. Scott Cairney described the importance of these findings:

This study offers an important insight into the impact of sleep on mental health. Besides post-traumatic stress disorder and depression, our findings might have implications for our understanding of other disorders linked to sleep disturbances, such as obsessive-compulsive disorder and schizophrenia.

These intrusions and lack of sleep feed into each other. If you experience many of these intrusions during the day, you will experience more trouble sleeping. The next day, your lack of sleep makes it harder to block intrusive thoughts. Disrupting this cycle is necessary for reducing the intrusive thought patterns and improving sleep.

Getting to Sleep Faster

Now you might be reaching the end of the article wondering about your sleeping habits. While sleep is a complex physiological process, luckily improving your sleeping habits is not rocket science! Here are some practical evidence-based tips.

Turn off your screens, set your phone on silent or airplane mode!

If your internet is off for seven or eight hours while you sleep, I promise you will not miss anything important. The only thing doom-scrolling at night will do is keep you awake longer. The light from your screen will also disrupt your sleep-wake cycles in the brain. Seriously, your phone’s airplane mode is your friend! If you find a screen limiting app like Focus, you can set it to block you from scrolling without going full airplane mode.

Keep the melatonin flowing!

During night time, a small brain region located near the bottom of your brain called the pineal gland creates a hormone called melatonin. This wonderful hormone helps our body initiate sleep processes. However, this process is light-sensitive. If there is light from your screen or elsewhere in your room, it will stop the production of melatonin. This is going to throw off your circadian rhythm which is responsible for regulating sleep-wake cycles.

So hello darkness, my old friend. I need you to help me fall asleep again.

Don’t drink coffee in the evening.

Coffee keeps you awake longer because it impersonates and blocks a signal in the brain that tells us we’re tired. Caffeine found in coffee looks remarkably like adenosine. Since they look so similar, brain cells might mistake caffeine for adenosine. But when they recognize caffeine with special receptors, it blocks adenosine from binding. While the caffeine is in your system, you’ll feel a lot less sleepy. Great in the morning, terrible at night!

Make your sleep into a consistent habit.

Like your cat that lays on your keyboard precisely when you need to write, you too should turn sleep into a habit. If your body becomes acclimated to sleeping and waking up around the same time every day, it will be easier to fall asleep on a whim. Who knows, it might even make waking up in the morning quicker and easier!

Treat yourself to better sleeping habits! This study emphasizes the importance of sleep towards our mental health, especially for depression or post-traumatic stress disorder. Getting enough sleep ensures that your brain will swat away negative thoughts and associations easily during the next day. Disrupt this cycle of poor sleep and negative thoughts. I hope you find use in some of these sleeping tips. Remember to mind your sleep and mind your mental health!