Parasomnias and Why Sleep Becomes Unstable at Night

What is Parasomnia?

Parasomnias are a category of sleep disorders involving abnormal behaviors or experiences during sleep or during the transitions between sleep and wakefulness.

These events can range from mild and harmless to intense or disruptive, both for the person experiencing them and for those around them.

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What are the types of parasomnias?

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Parasomnias are broadly grouped based on which stage of sleep they arise from. Some occur during non-REM sleep, typically deep sleep early in the night, while others are linked to REM sleep, when dreaming is most active. 

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Non-REM Parasomnias

Sleepwalking (Somnambulism)

Sleepwalking happens when a person gets out of bed and begins moving around while still asleep. People who sleepwalk often have their eyes open and may perform routine or strange activities, such as walking through the house, opening doors, or rearranging objects. 

Sleepwalking can become dangerous because the person is not aware of their surroundings and may encounter stairs, sharp objects, or even attempt to leave the house, but the episode itself is not harmful to the body.

Night Terrors (Sleep Terrors)

Night terrors are sudden episodes of intense fear that occur during deep sleep, where a person may scream, thrash, sit upright in bed, or appear panicked and inconsolable. 

Night terrors are most common in children, but they also affect adults. Around 2 to 3 percent of adults experience recurrent night terrors, though occasional episodes are likely underreported. 

In adults, night terrors are more strongly associated with nervous system stress rather than developmental factors, with the most common triggers including chronic stress, sleep deprivation, and irregular sleep schedules.

Confusional Arousals

Confusional arousals happen when someone partially wakes from deep sleep and appears confused, disoriented, or slow to respond. The person may sit up in bed, mumble, or act strangely without fully waking. 

These episodes typically last a few minutes and end with the person returning to sleep, with little or no memory of what happened.

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REM-Related Parasomnias

Sleep Paralysis

During certain REM transitions, consciousness can return before muscle control does. In those moments, a person is aware but unable to move or speak. This mismatch between a waking mind and a sleeping body is often accompanied by intense sensations, such as pressure on the chest or the feeling that someone is nearby. 

REM Sleep Behavior Disorder

In REM sleep, the body is normally kept still while the brain dreams. When that protective paralysis weakens, dream content can spill into physical action. People may shout, gesture, strike, or suddenly move in ways that mirror what they are dreaming. 

Unlike non-REM parasomnias, these episodes are often followed by clear recollection of vivid or emotionally charged dreams.

Nightmare Disorder

Some REM parasomnias involve perception rather than movement. Nightmare disorder is marked by recurring, intensely distressing dreams that lead to full awakening. 

Because these episodes arise from REM sleep, the dream narrative is usually remembered in detail, and the emotional response can linger long after waking, making it difficult to fall back asleep.

Sleep-Related Hallucinations

At the boundary between sleep and wakefulness, elements of REM dreaming can intrude into conscious awareness. This can produce vivid visual, auditory, or tactile hallucinations that feel real in the moment. 

These experiences often overlap with sleep paralysis but may also occur on their own, reflecting the same instability between dreaming sleep and wakefulness.

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Causes and Contributing Factors

Parasomnias rarely have a single cause. They usually arise from a combination of underlying vulnerability and triggering factors.

Genetics and family history play a role, especially in sleepwalking and night terrors. 

In family studies, researchers found that 80 percent of sleepwalking pedigrees and as many as 96 percent of night terror pedigrees included one or more affected relatives, suggesting a strong hereditary component rather than purely random occurrence. 

In addition, large cohort research has shown that children with one sleepwalking parent are roughly three times more likely to sleepwalk themselves, and those with two affected parents have up to seven times the risk compared with children whose parents never sleepwalked. 

Stress, anxiety, and emotional strain are also a contributing factor. A nervous system that remains on high alert during the day often carries that tension into sleep, increasing the likelihood of partial awakenings and abnormal behaviors at night.

Sleep deprivation and irregular schedules strongly increase parasomnia risk because prolonged wakefulness increases sleep pressure, leading to deeper but less stable sleep and a higher likelihood of incomplete awakenings.

Medications and substances, including certain antidepressants, sedatives, sleep aids, and alcohol, can disrupt normal sleep architecture and increase parasomnia episodes in susceptible individuals.

For alcohol specifically, large observational data show that people who regularly consume alcohol in the evening report higher rates of sleep disturbances, with nearly 90 percent of regular evening drinkers reporting at least one sleep problem, including nightmares or fragmented sleep that can make parasomnia episodes more likely.

Moderate to heavy drinking has also been linked with a 23 percent higher likelihood of probable REM-related parasomnia symptoms compared with nondrinkers.

Other sleep or medical conditions, such as sleep apnea, restless legs syndrome, chronic pain, or neurological disorders, can fragment sleep and create repeated arousals that trigger parasomnias.

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Potential Dangers Of Parasomnia

Because parasomnias typically happen without awareness, symptoms are usually noticed indirectly or reported by others. Some people feel excessively tired during the day even after spending enough time in bed, because parasomnia episodes disrupt deep, restorative sleep.

In many cases, parasomnias are more disruptive than dangerous. However, they can pose real risks when behaviors involve movement, confusion, or lack of coordination. 

Sleepwalking, in particular, can lead to injuries, and violent movements during dream-related parasomnias can also put bed partners at risk. 

Because of this, repeated or intense parasomnia episodes should not be ignored.

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The Role of Sleep Quality and Sleep Stages

Sleep is organized into stages, but what matters just as much as the stages themselves is how consistently the brain is able to move through them. 

During a stable night of sleep, transitions between light sleep, deep sleep, and REM sleep occur gradually and predictably, allowing each stage to perform its role without interruption.

Parasomnias emerge when that structure breaks down. Instead of completing one stage before moving into the next, the brain activates unevenly, creating mixed states where elements of sleep and wakefulness overlap. 

The result is behavior or perception without full awareness.

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How Kimba Helps You Sleep More Peacefully

Kimba is a scent-based personal limbic therapy system designed to support sleep stability in real time.

When Kimba detects that your sleep is becoming lighter or that your nervous system is shifting toward alertness, it releases a short, precisely timed pulse of scent. These scents work through the olfactory pathway, which connects directly to the limbic system, the part of the brain involved in emotional regulation, safety, and threat detection.

Because scent reaches these brain regions without requiring conscious awareness, it can help signal calm and safety at the exact moments when sleep is at risk of breaking down. Over time, the brain learns to associate these cues with relaxation, making it easier to stay in deeper, more stable sleep.

For people prone to parasomnias, this kind of support can reduce the frequency of partial awakenings that trigger episodes. 

Get early access to Kimba and discover what it can do for your nights!

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