Parasomnias are disruptive sleep disorders that can occur during arousals from REM sleep or partial arousals from non-REM sleep. Parasomnias include nightmares, night terrors, sleepwalking, confusional arousals, and many others.
Nightmares are vivid nighttime events that can cause feelings of fear, terror, and/or anxiety. Usually, the person having a nightmare is abruptly awakened from REM sleep and is able to describe detailed dream content. Returning to sleep is usually difficult. Nightmares can be caused by many factors, including illness, anxiety, the loss of a loved one, or negative reactions to a medication. Call your doctor if nightmares occur more than once a week or if nightmares prevent you from getting a good night's sleep for a prolonged period of time.
A person experiencing a night terror abruptly awakes from sleep in a terrified state, but is confused and unable to communicate. They do not respond to voices and are difficult to fully awaken. Night terrors last about 15 minutes, after which time the person usually lies down and appears to fall back asleep. People who have night terrors (sometimes called sleep terrors) usually don't remember the events the next morning. Night terrors are similar to nightmares, but usually occur during deep sleep.
People experiencing sleep terrors may pose dangers to themselves or others because of limb movements. Night terrors are fairly common in children, mostly between ages 3 and 8. Children with sleep terrors will often also talk in their sleep or sleepwalk. This sleep disorder, which may run in families, also can occur in adults. Strong emotional tension and/or the use of alcohol can increase the incidence of night terrors among adults.
Sleepwalking occurs when a person appears to be awake and moving around, but is actually asleep. He or she has no memory of the episode. Sleepwalking most often occurs during deep non-REM sleep (stages 3 and 4 sleep) early in the night and it can occur during REM sleep in the early morning. This disorder is most commonly seen in children between ages 5 and 12; however, sleepwalking can occur among younger children, adults, and seniors.
Sleepwalking appears to run in families. Contrary to what many people believe, it is not dangerous to wake a person who is sleepwalking. The sleepwalker simply may be confused or disoriented for a short time upon awakening. Although waking a sleepwalker is not dangerous, sleepwalking itself can be dangerous, because the person is unaware of his or her surroundings and can bump into objects or fall down. In most children, it tends to stop as they enter the teen years.