09 May Haunted by the past: old emotions remain salient in insomnia disorder
How to deal with embarrassing memories? Surprisingly, getting more sleep.
Wassing et al. from the Netherlands Institute for Neuroscience have recently shown that people with insomnia are not able to neutralise embarrassing mistakes and emotional distress that happen a long time ago.
The scientists asked participants to relive their most shameful experiences of decades ago while making MRI scans of their brain activity. While good sleepers literally settled those experiences in their head as neutralised memories, people with insomnia were not able to do so. This breakthrough finding suggests that insomnia could primarily be caused by a failing neutralisation of emotional distress.
These findings were published on 25 April in the Journal; Brain. It has importance because it is an approach to understand the relationship between insomnia and the development of mood disorders, anxiety, and post-traumatic stress.
Maladaptive sleep: It is well-known that sleep helps us to remember important experiences. But sleep is also essential for getting rid of the emotional distress that may have occurred during those experiences. Both of these overnight processes involve changes in the connections between brain cells: some become stronger and consolidate memories, whereas others are weakened and get rid of unwanted associations.
“Sayings like ‘sleeping on it’ to ‘get things off your mind’ reflect our nocturnal digestion of daytime experiences. Brain research now shows that only good sleepers profit from sleep when it comes to shedding emotional tension. The process does not work well in people with insomnia. In fact, their restless nights can even make them feel worse” – Rick Wassing.
Karaoke: New brain imaging may explain a recent finding from Wassing et al. published in the scientific journal Sleep. In this study, they asked participants to sing along karaoke-style. Headphones prevented them from hearing their own voice and finding the correct pitch. Their singing was recorded and played back later. Participants felt intense shame when listening to their own out-of-tune solo singing. But if they listened once more after a good night’s sleep, they didn’t feel that distressed about it anymore. They had literally got the distress off their minds. At least: good sleepers did. After a restless night, people with insomnia were in fact even more upset about it.
Emotion: Scientists have been searching for causes of insomnia in brain areas that regulate sleep. The new findings suggest that causes of insomnia are likely to be found in brain circuits that regulate emotions. These circuits contain risk genes for insomnia and may not activate properly during rapid eye movement sleep. Without the benefits of sound sleep, distressing events of decades ago continue to activate the emotional circuits of the brain as if they are happening right now. Scientists Rick Wassing, Frans Schalkwijk and Eus van Someren have seemingly shown that people with insomnia are haunted by memories of past distress.
Wessler et al. are the first to experimentally show that the benefits of sleep are not only lost when sleep is poor but people with insomnia experience a maladaptive type of sleep that actually aggravates physically perceived distress. Maladaptive sleep could shed new light on post-traumatic stress disorder (PTSD) and on diurnal mood fluctuation and the favourable effects of sleep deprivation in depression.
- Rick Wassing, Frans Schalkwijk, Oti Lakbila-Kamal, Jennifer R Ramautar, Diederick Stoffers, Henri J M M Mutsaerts, Lucia M Talamini, Eus J W Van Someren, Haunted by the past: old emotions remain salient in insomnia disorder, Brain, , awz089, https://doi.org/10.1093/brain/awz089
- Rick Wassing, Jeroen S Benjamins, Lucia M Talamini, Frans Schalkwijk, Eus J W Van Someren. Sleep. Overnight worsening of emotional distress indicates maladaptive sleep in insomnia. doi:10.1093/sleep/zsy268