Sleepwalking, nightmares, sleep terrors, and sleep paralysis are all examples of parasomnias, a group of sleep disorders involving unusual behaviors or experiences during sleep or while falling asleep or waking up.

Some parasomnias involve movements or actions that a person may not remember afterward. Others involve vivid dreams or frightening sensations that feel very real. While some episodes are brief and harmless, others can disrupt sleep, cause distress, or create safety concerns.

The effects can also extend beyond the night, affecting how someone feels and functions during the day.

This page explains the different types of parasomnias, their common symptoms, and when to seek help.

Parasomnias can look and feel very different depending on the condition. Some involve unusual behaviors during sleep, while others cause frightening experiences when falling asleep or waking up.

Common signs and symptoms include:

• Unusual behaviors during sleep: Walking, sitting up, shouting, or appearing frightened without being fully awake.
• Disturbing dreams: Vivid nightmares that cause fear or distress and are often remembered after waking.
• Sleep paralysis: Being temporarily unable to move or speak while falling asleep or waking up.
• Unusual sensations: Hearing sounds, seeing images, or feeling sensations that seem real while falling asleep or waking up, even when there is no external cause.
• Confusion or fear: Feeling disoriented or frightened during or after an episode, sometimes with a racing heart.
• Little or no memory: Being unaware of behaviors or events that a bed partner or family member observed.
• Disrupted sleep and daytime effects: Feeling tired, having difficulty concentrating, or worrying about going to sleep.
• Safety concerns: Injuries or potentially dangerous movements during sleep, which can also affect a bed partner.

Not everyone experiences the same symptoms, and their frequency and severity can vary. Some episodes are harmless, while others may require further evaluation.

Many parasomnias are harmless, but some can cause distress, disrupt sleep, or create safety risks. Knowing when to seek help can make it easier to identify an underlying problem and find appropriate treatment.

Seek urgent medical attention if an episode involves a serious injury, difficulty breathing, prolonged confusion, or signs of a possible seizure.

Talk with a healthcare professional if:

• Episodes happen frequently, become more severe, or start unexpectedly.
• Sleepwalking, violent movements, or other behaviors put you or someone else at risk of injury.
• Sleep disturbances affect your daytime alertness, mood, or ability to manage everyday activities.
• Episodes occur alongside excessive daytime sleepiness, loud snoring, or breathing pauses during sleep.
• Symptoms begin or worsen after a change in medication or substance use.

Parasomnias are often diagnosed based on a person’s symptoms and medical history. A healthcare professional will ask what happens during an episode, when it occurs, and whether the person remembers it afterward. They may also review sleep habits, medications, and other health conditions.

Because people are not always aware of what happens during sleep, observations from a bed partner or family member can be particularly helpful. A sleep diary or home video of an episode may also provide useful information.

In some cases, an overnight sleep study with video monitoring may be recommended. This can help distinguish parasomnias from other conditions, such as nighttime seizures or sleep apnea. It may also be needed when episodes involve unusual or potentially dangerous behaviors.

Not everyone needs a sleep study. The assessment depends on the symptoms and whether another condition may be contributing to the episodes.

For more information about specific parasomnias and how they are diagnosed, explore the individual condition pages above.

Managing parasomnias depends on the type of condition and how often episodes occur. Getting enough sleep and maintaining a regular sleep schedule can help reduce certain parasomnias, particularly sleepwalking and sleep terrors.

Stress, some medications, and untreated sleep disorders can also contribute to episodes. Identifying these factors with a healthcare professional may help reduce symptoms.

For parasomnias involving movement, making the sleeping environment safer can help prevent injuries. Treatment may also be needed when episodes are frequent, distressing, or potentially dangerous.

Explore the various types of parasomnias using the topics cards above to learn about specific treatment and management approaches for each condition.