Most people associate sleepwalking with children, so when it happens in adulthood, it tends to catch people off guard — and concern them in ways it never did when they were young. If you or someone close to you has been getting up in the night, moving around, and having no memory of it the next morning, understanding what causes sleepwalking in adults is the right place to start. At uNITE Sleep Institute, we evaluate and treat a full range of sleep disorders, including parasomnias like sleepwalking, and we see firsthand how disruptive and even dangerous this condition can be when left unaddressed.
What Sleepwalking Actually Is
Sleepwalking, known clinically as somnambulism, is classified as a non-REM parasomnia. It occurs during the deep stages of sleep, typically in the first third of the night, when the brain is in its most restorative phase. During a sleepwalking episode, the brain partially arouses from deep sleep while the body remains capable of movement. The result is a person who appears to be awake — walking, talking, sometimes even performing complex tasks — but is not conscious in any meaningful sense and will have little to no memory of the episode afterward.
Episodes can range from simply sitting up in bed to walking through the house, going outside, or attempting to drive. The behavior can look purposeful and coordinated from the outside, which makes it especially unsettling for anyone who witnesses it. Understanding what causes sleepwalking in adults matters not just for peace of mind but because identifying the underlying reasons for sleepwalking in adults is often the key to making it stop.
The Most Common Reasons for Sleepwalking in Adults
Sleep Deprivation
One of the most well-established reasons for sleepwalking in adults is chronic sleep deprivation. When the body is consistently deprived of deep, restorative sleep, the pressure to enter slow-wave sleep becomes intense. That pressure can trigger partial arousals and increase the likelihood of parasomnia events. Patients who work irregular hours, struggle with insomnia, or have underlying sleep disorders that fragment their sleep are at elevated risk for episodes. At uNITE Sleep Institute, sleep deprivation is one of the first factors we evaluate when a patient presents with sleepwalking concerns.
Stress and Anxiety
Psychological stress is another major contributor to what causes sleepwalking in adults. Elevated stress and anxiety affect the brain's ability to transition smoothly through sleep stages, disrupting the normal architecture of a night's sleep and increasing the frequency of partial arousals from deep sleep. Patients going through significant life stressors — career pressure, relationship difficulties, financial strain, or grief — often report that sleepwalking episodes increase in frequency during those periods. Addressing the psychological dimension is an important part of a comprehensive evaluation.
Alcohol and Sedative Medications
Alcohol is a particularly disruptive variable when it comes to sleep architecture. While it may help a person fall asleep faster, it suppresses REM sleep and causes more frequent arousals in the second half of the night, destabilizing the transitions between sleep stages. Sedative medications, including certain sleep aids, benzodiazepines, and some antihistamines, can have similar effects. Identifying what causes sleepwalking in adults often involves a careful review of substance use and medication history, because the connection between sedatives and parasomnia events is well-documented and frequently overlooked.
Underlying Sleep Disorders
One of the reasons for sleepwalking in adults that uNITE Sleep Institute pays particular attention to is the presence of an undiagnosed or undertreated sleep disorder. Obstructive sleep apnea is a significant contributor. When the airway repeatedly closes during sleep, the brain is forced into partial arousal to restore breathing, and those micro-arousals from deep sleep are exactly the kind of disruption that triggers sleepwalking events. Restless leg syndrome can have a similar effect, as the discomfort it creates prevents the body from settling into sustained deep sleep.
For many adults who are surprised to find themselves sleepwalking later in life, an undiagnosed case of obstructive sleep apnea turns out to be the driving factor. Treating the apnea frequently resolves the sleepwalking entirely. This is one of the most important reasons why a thorough sleep evaluation matters so much when sleepwalking begins or worsens in adulthood.
Genetics and Family History
Sleepwalking has a strong genetic component. Adults with a first-degree relative who sleepwalked are significantly more likely to experience it themselves. A family history does not guarantee episodes will occur, but it does indicate a predisposition that can be activated by other triggers — stress, sleep deprivation, illness, or medication changes. When patients at uNITE Sleep Institute report a family history of parasomnias, we use that context to guide our evaluation and look more carefully for any contributing factors that may be tipping a genetic predisposition into active episodes.
Fever and Illness
Acute illness and fever can temporarily increase the frequency of sleepwalking in adults who are already predisposed to it. High body temperature affects the brain's ability to regulate sleep stages, and the physiological stress of illness can push the nervous system toward the kind of partial arousals that produce parasomnia behavior. For most patients, sleepwalking episodes that occur during illness resolve once they recover. If they persist beyond recovery, that is a signal worth discussing with a sleep medicine provider.
When Sleepwalking Becomes a Safety Concern
The most immediate concern with adult sleepwalking is physical safety. An adult in the middle of an episode has impaired judgment and no conscious awareness of their surroundings, which means falls, burns, cuts, and far more serious accidents are genuine risks. Some adults have been found outside their homes, in the street, or attempting to drive, with no memory of leaving their bed. For anyone in a shared living situation, an episode can also be frightening and disorienting for the people who witness it.
Understanding what causes sleepwalking in adults is important precisely because addressing those causes — rather than simply trying to manage episodes after the fact — is the path to lasting improvement. Safety measures like locking doors and windows and removing obstacles from the bedroom floor can reduce immediate risk, but they do not address the underlying sleep disturbance driving the behavior.