Sleepwalking is not a mental illness. It is classified as a sleep disorder, specifically a “disorder of arousal” that happens when the brain gets stuck between deep sleep and wakefulness. While sleepwalking can occur alongside conditions like depression or anxiety, it is a distinct neurological event with its own diagnostic criteria, strong genetic roots, and well-understood brain mechanisms.
What Sleepwalking Actually Is
In the DSM-5, the manual used to classify psychiatric and behavioral conditions, sleepwalking falls under parasomnias, not mental disorders. The diagnostic criteria describe repeated episodes of getting out of bed during sleep and walking around with a blank, staring expression, being unresponsive to others, and being difficult to wake. People typically have little or no memory of the episode afterward.
The distinction matters because sleepwalking can look alarming. A person might move through the house, open doors, or display strange behavior, all while being essentially unconscious. These episodes can easily be confused with psychiatric conditions. As one review in a psychiatry journal noted, “admixtures of sleep phenomena and elements of wakefulness can easily be confused with primary psychiatric disorders,” particularly when bizarre behavior during an episode gets misinterpreted as psychosis. But the underlying mechanism is fundamentally different.
What Happens in the Brain During an Episode
During a sleepwalking episode, the brain is literally split between sleeping and waking. Brain imaging studies have shown that motor areas, the emotional processing center (the amygdala), and parts of the brain involved in movement and sensation display wake-like electrical activity. Meanwhile, the regions responsible for higher-level thinking, judgment, decision-making, and memory formation remain in deep sleep. This is why a sleepwalker can navigate a room and even perform complex actions but has no awareness of what they’re doing and no memory of it afterward. It’s not a psychological break from reality. It’s a glitch in the transition between sleep stages.
The Link to Depression, Anxiety, and Other Conditions
Here’s where the question gets more nuanced. Sleepwalking isn’t a sign of mental illness, but it does show up more often in people who have certain psychiatric conditions. A large study from Stanford found that people with depression were 3.5 times more likely to sleepwalk than people without it. Alcohol dependence and obsessive-compulsive disorder were also significantly associated with higher rates of sleepwalking.
This doesn’t mean depression causes sleepwalking or that sleepwalking signals hidden depression. The relationship is more indirect. Depression and anxiety frequently disrupt sleep architecture, the normal progression through sleep stages over the course of a night. When deep sleep is fragmented or destabilized, the conditions for a sleepwalking episode become more favorable. The psychiatric condition isn’t producing the sleepwalking so much as creating a sleep environment where it’s more likely to happen.
Certain medications used to treat psychiatric conditions can also trigger sleepwalking. A systematic review identified 29 drugs across four main categories that have been linked to sleepwalking episodes: sleep aids that act on GABA receptors (with the strongest evidence for zolpidem), antidepressants, antipsychotics, and beta-blockers. So in some cases, it’s the treatment for a mental health condition, not the condition itself, that’s behind the episodes.
Genetics Play a Major Role
One of the strongest arguments against sleepwalking being a psychiatric symptom is how heritable it is. If one of your parents or siblings sleepwalks, your risk is roughly 10 times higher than someone without that family history. Twin studies put numbers on the genetic contribution: in childhood sleepwalking, genetics accounted for 57 to 66 percent of the variation, depending on sex. In adults, the genetic influence was as high as 80 percent in men.
Identical twins are far more likely to share the trait than fraternal twins. In adults, the concordance rate (both twins sleepwalking) was 32 percent for identical twins versus just 6 percent for fraternal twins. This pattern points clearly to a biological predisposition that runs in families, independent of any psychiatric diagnosis.
When Sleepwalking Deserves Attention
Most children who sleepwalk grow out of it by adolescence, and occasional episodes in adults are common and harmless. But sleepwalking that starts or worsens in adulthood, happens frequently, or puts you at risk of injury is worth investigating. The goal isn’t to look for a hidden mental illness. It’s to identify what’s disrupting your sleep enough to trigger episodes.
Common culprits include sleep deprivation, irregular sleep schedules, untreated sleep apnea, stress, fever, and certain medications. Addressing these underlying triggers often reduces or eliminates episodes entirely. For people with frequent sleepwalking, a technique called anticipatory awakening can help: setting an alarm for about 15 minutes before episodes typically occur, staying awake briefly, then going back to sleep. This interrupts the sleep cycle pattern that leads to episodes.
Practical safety steps matter too. Locking windows and exterior doors, removing sharp or breakable objects from pathways, sleeping on the ground floor if possible, and keeping the bedroom environment clear of obstacles can prevent injury during an episode. These measures are straightforward but make a real difference, especially for people who sleepwalk regularly.