Sleep affects the brain in a number of ways, one of the most important of which is our ability to function emotionally. This review outlines recent advances in the study of sleep and emotions, focusing on the emotional benefits of getting enough sleep, and the possible detriments which result from a lack of sleep.
Impact of Sleep Loss:
Sleep loss is consistently linked with feelings of irritability and poor control over emotions. Sleep loss amplifies negative emotions in reaction to disturbances during the day and blunts positive emotions that normally come from achieving goals during the day. These changes are caused by an increase in the reactivity of the amygdala brought on by lack of sleep.
Emotion Recognition and Sleep Loss
Low levels of sleep can interfere with our ability to recognise facial expressions in other people and also reduces our ability to express emotions. After just a single bad night of sleep our ability to express emotion vocally and through facial expressions is reduced.
Benefits of Sleep:
Conditioning and Fear Learning
In the learning process known as conditioning, neutral items (e.g., a tone) are repeatedly paired with a coinciding unpleasant event (unconditioned stimulus, e.g., electric shock), triggering fear reactions. After an association is formed between these two stimuli, the presentation of the previously neutral item alone (now referred to as the conditioned stimulus, the tone) is sufficient to elicit a conditioned fear response. This process of conditioning is an essential part of learning how to react to the world around us, and sleep can affect is in a number of ways.
Sleep strengthens a conditioned fear response by strengthening fear-related memories, allowing you to better discriminate between fear-related stimuli and non fear-related. Sleep can also help to extinguish fear responses if the conditioned stimulus is constantly encountered without the unconditioned stimulus. Getting the right amount of sleep has also been shown to help with the expression of fear and with our ability to express or suppress fear in a way that it appropriate to individual situations.
REM sleep helps to consolidate emotion-related memories and help you separate emotionally important information from background or unimportant information. This makes it more likely that you will be able to recall the important, emotionally charged information years later while discarding the non important information.
One of the most interesting effects of REM sleep is the way it helps us deal with emotional and traumatic events that happened the day before. The way the brain processes emotional memories during sleep strengthens the memory and makes them more likely to be remembered, but at the same time softens the emotional aspect of the memory. This makes unpleasant memories less traumatic to recall. So sleep helps us remember the factual side of emotional memories and helps us reduce the emotional content of highly unpleasant of traumatic memories.
So getting a good sleep helps you deal with traumatic occurrences from the previous day. But it also prepares us for the next day’s events by restoring our emotional “senses” to their optimal state. During sleep the brain restores its ability to discriminate between different emotions and accurately perceive different emotions.
Implications for Psychiatric Conditions:
These findings relating to the importance of sleep and the dangers of sleep deprivation offer new insights into the role of sleep in different mental disorders.
Post-traumatic Stress Disorder can interfere with the amount and quality of REM sleep a person experiences. This means that they do not benefit from the emotional healing qualities of REM sleep and their traumatic memories remain just as fresh and raw. Rates of insomnia are often high in those with PTSD, such as war veterans, meaning that insomnia treatment is essential in healing from the painful experiences such people have been through.
Depression, on the other hand, increases the amount of REM sleep a person experiences. Too much REM sleep causes the brain to become overly sensitive and to react negatively to irrelevant information, while reducing our ability to discriminate between positive and negative information around us. This helps to explain why people with depression struggle to interpret things around them as being good and often see everything as being bad. Again, rates of insomnia and sleep disorders are high in those with depression, meaning that learning how to treat insomnia would also be very useful in learning to treat depression.
New research shows that sleep is incredibly important for our ability to recognise, express and process emotions, while sleep deprivation reduces our ability to function on an emotional level. Further research into insomnia cures and treatment is therefore vital in helping people with any kind of sleep disorder to experience emotions in a healthy way.
If you struggle with getting enough sleep and want to find out more about how to treat insomnia, please get in touch.