Les cauchemars, souventdes rêves très vivants et troublants, peuvent perturber considérablement votre sommeil, provoquant terreur et désorientation au réveil. Entre 50 % et 85 % des adultes américains en font l’expérience, avec jusqu’à 5 % souffrant de troubles du sommeil associés. Ce texte explore les mécanismes cérébraux des cauchemars et leurs éventuels liens avec des traumatismes. Il distingue les cauchemars des terreurs nocturnes et examine leur représentation dans la culture populaire, suggérant qu’ils peuvent offrir un aperçu de la complexité de l’esprit humain.
Darkness envelops you.
Imagine the hairy legs of a tarantula crawling across your face. A snake winds around your legs while fins approach, inching closer as you navigate murky waters.
You run frantically from a looming monster. Your teeth crumble out of your mouth. You find yourself in front of a crowd wearing just your underwear…
Suddenly, you wake up. Sweat trickles down your face, and your heart pounds in the stillness of your bedroom. Your senses struggle to find balance. Take a deep breath. You’re alright. You’re secure.
It was just a nightmare.
The Nature of Nightmares
Nightmares can spoil your entire night. They intrude with vivid, horrifying dreams that thrust us into a midnight purgatory, where we lie half-awake and shaken in the dark. Fear and anxiety often accompany a mind haunted by nightmares, lingering as it attempts to reconcile the traumatic dream with the jarring return to reality.
This experience is quite common. Research indicates that 50% to 85% of adults in the U.S. occasionally have nightmares, and up to 5% suffer from regular nightmares due to nightmare disorder. For these individuals, persistent nighttime episodes are classified as a type of parasomnia, a disruptive sleep disorder. Conditions like sleep paralysis are recognized examples of parasomnias that significantly impact sleep quality and everyday life.
However, when these nightmares begin to disrupt your sleep patterns and invade your thoughts while awake, it becomes a pressing concern.
Gemma Simpson, a psychology student, has been battling disruptive nightmares for over a decade, which consistently interfere with her sleep and daily activities.
‘After a nightmare, my sleep quality is usually worse,’ she remarked. ‘The dreams are always so vivid; I unintentionally obsess over them for days until the shock starts to fade.’
She describes her nightmares as often nonsensical yet profoundly traumatic, frequently featuring violence and distressing scenarios.
‘I once dreamed that my dad was beating me with an aluminum baseball bat in an art gallery,’ she shared. ‘The specific setting was strange… I’ve also had nightmares involving sexual assault and violence.’
Being a psychology student, Simpson is aware of Freud’s dream theories, which suggest dreams express repressed desires and emotions that the mind needs to process.
‘Memory consolidation occurs during sleep,’ she explained. ‘I believe that on the days I have nightmares, I might encounter something that triggers my traumas, even if I don’t consciously acknowledge it at the time.’
Dan Ford, a sleep psychologist at Auckland’s Better Sleep Clinic, states that trying to interpret dreams after waking can only be beneficial if it brings comfort.
‘The general idea is that something isn’t right, leading to the nightmares; I’d suggest keeping interpretations simple,’ he advised. ‘Dreams tend to be quite absurd.’
‘You may spend time focusing on something of little significance. If the content relates to a recurring trauma, deeper interpretation may not be necessary.’
Common Triggers of Nightmares
If you experience nightmares infrequently, such as once every couple of weeks, it’s usually straightforward to identify potential triggers. Common causative factors include:
Understanding Brain Activity During Sleep
The human brain goes through four stages of sleep throughout the night.
The Four Stages of Sleep
Each stage is marked by distinct brain and bodily functions, indicating how deeply someone is sleeping, often measured via an electroencephalogram (EEG).
It typically takes up to 90 minutes of sleep to enter REM sleep, meaning you likely aren’t dreaming immediately after falling asleep.
‘For most people, nightmares are more likely to occur in the latter part of the night,’ Ford explained.
Nightmares happen only during REM sleep, the phase when brain activity is heightened. Some individuals may experience elements of limb paralysis during stage four, although that scenario is uncommon. Others may undergo various sleep disturbances that can be frightening in their own right.
‘In essence, we are processing emotions,’ Ford noted. ‘If someone is hyper-aroused, their sympathetic nervous system may be triggered, impacting their sleep and contributing to nightmares.’
Nightmares vs. Night Terrors
Despite their similar names, nightmares and night terrors are quite different experiences.
During my teenage years, I often babysat. One night, I filled in for a friend’s shift with a new family. Everything seemed fine until the children went to bed. About 40 minutes into sleep, a