Sleepwalking usually occurs early in the night — often one to two hours after falling asleep. It's unlikely to occur during naps. A sleepwalking episode can occur rarely or often, and an episode generally lasts several minutes, but can last longer.

Someone who is sleepwalking may:

• Get out of bed and walk around
• Sit up in bed and open his or her eyes
• Have a glazed, glassy-eyed expression
• Not respond or communicate with others
• Be difficult to wake up during an episode
• Be disoriented or confused for a short time after being awakened
• Not remember the episode in the morning
• Have problems functioning during the day because of disturbed sleep
• Have sleep terrors in addition to sleepwalking

Sometimes, a person who is sleepwalking will:

• Do routine activities, such as getting dressed, talking or eating
• Leave the house
• Drive a car
• Engage in unusual behavior, such as urinating in a closet
• Engage in sexual activity without awareness
• Get injured, for example, by falling down the stairs or jumping out a window
• Become violent during the period of brief confusion immediately after waking or, occasionally, during sleepwalking

Sleepwalking is classified as a parasomnia — an undesirable behavior or experience during sleep. Sleepwalking is a disorder of arousal, meaning it occurs during N3 sleep, the deepest stage of non-rapid eye movement (NREM) sleep. Another NREM disorder is sleep terrors, which can occur together with sleepwalking.

Many factors can contribute to sleepwalking, including:

• Sleep deprivation
• Stress
• Fever
• Sleep schedule disruptions, travel or sleep interruptions

Sometimes sleepwalking can by triggered by underlying conditions that interfere with sleep, such as:

• Sleep-disordered breathing — a group of disorders featuring abnormal breathing patterns during sleep (for example, obstructive sleep apnea)
• Taking certain medications, such as hypnotics, sedatives or certain medications used for psychiatric disorders
• Substance use, such as alcohol
• Restless legs syndrome
• Gastroesophageal reflux disease (GERD)

Factors that may increase the risk of sleepwalking include:

• Genetics. Sleepwalking appears to run in families. It's more common if you have one parent who has a history of sleepwalking, and much more common if both parents have a history of the disorder.
• Age. Sleepwalking occurs more often in children than adults, and onset in adulthood is more likely related to other underlying conditions.

Sleepwalking itself isn't necessarily a concern, but a person who sleepwalks can:

• Hurt themselves — especially if they walk near furniture or stairs, wander outdoors, drive a car or eat something inappropriate during a sleepwalking episode
• Experience prolonged sleep disruption, which can lead to excessive daytime sleepiness and possible school or behavior issues
• Be embarrassed or experience problems with social relationships
• Disturb others' sleep
• Rarely, injure someone else nearby