Strange Behavior During Sleep

Parasomnias are common sleep disorders. They are characterized by strange or bizarre behavior or experiences during sleep. Parasomnias can occur during specific stages of sleep or during the transition between sleeping and waking.

These are the most common parasomnias:

  • Nightmares and nightmare disorder
  • REM Sleep Behavior Disorder 
  • Sleep terrors
  • Sleepwalking/talking


Nightmares are frightening dreams that jolt the sleeper awake suddenly. People usually remember vivid details about their nightmares. Having the same nightmare over and over is called a nightmare disorder.

In adults, nightmares are often connected with conditions such as post-traumatic stress disorder, depression, and schizophrenia. They can happen more often during stressful life situations, such as the death of a loved one, a breakup or divorce, or loss of a job. They can also be related to certain medicines, such as antidepressants, narcotics, or seizure medicines.

REM Sleep Behavior Disorder

For most people, dreams occur in our mind while our body is at rest. People who suffer from REM sleep behavior disorder lack muscle paralysis that typically occurs during REM sleep and will instead act out their dreams. When this occurs, it causes the person to engage in activities associated with their dreams such as walking, shouting, hitting, or punching. This may result in injury to their bed partner or the sleeping person themselves. 

Sleep Terrors 

Sleep terrors, also known as night terrors, are episodes of fear, confusion, and screaming during sleep. Toddlers who have sleep terrors may try crawling or walking in their sleep. If this happens, parents will need to watch them closely so that they don't hurt themselves. Sleep terrors usually last a few seconds to a few minutes and often occur with sleepwalking. Unlike a nightmare, a person having a sleep terror will not wake up and will not remember anything the next morning. Although usually short, sleep terrors can last up to 45 minutes.

Nightmares and sleep terrors are more common in children than adults. In children, they are rarely caused by a physical or mental illness. Both nightmares and sleep terrors are more common in people with other sleep problems, such as obstructive sleep apnea.


Sleepwalking, also known as somnambulism, is a disorder in which a person partially wakes up during the night and walks around without realizing it. The sleepwalker might make repetitive movements, such as fumbling with clothing, get out of bed and stroll around, or even talk to you. Sleepwalking is usually not a cause for concern. Most children will outgrow sleepwalking by their teenage years.