You brush your teeth, slip under the covers and turn off the lights, but if you think that's always the end of the story, you're wrong.
Sleepwalking is far more common than previously thought, affecting nearly one-third of adults at some point in their lives, according to the first major study to assess the disorder's prevalence in the U.S. in more than three decades.
"This is a big number," said Dr. Maurice Ohayon, director of the Sleep Epidemiology Research Center at Stanford University and an author on the study. "The question that follows is 'do we find some associations that are meaningful for sleepwalking?' And the answer is yes."
Sleepwalking is a type of parasomnia -- a category of common sleep disorders including things like sleep-related eating, night terrors and sleep paralysis -- that affects about 10 percent of Americans, according to the National Sleep Foundation. Sleepwalking typically occurs during non-REM sleep and can last from a few seconds to 30 minutes or more.
For the study, researchers relied on the broader term "nocturnal wandering," as they were unable to observe patients in a lab and give them a diagnosis. The possibility therefore remained that among the more than 15,000 adults who researchers interviewed about their sleep habits, some experienced wandering that occurred when they were actually awake, just very confused.
According to the findings, nearly 30 percent of the participants reported at least one experience with nocturnal wandering at some point in their lives, and more than 3.5 percent said they'd experienced it in the past year. A small group indicated they dealt with it regularly; 1 percent reported having two or more episodes per month. The results were published in the journal Neurology on Monday.
In addition to tracking prevalence, the researchers also looked at other conditions linked with sleepwalking in order to unpack possible causes or triggers of the disorder.
They found certain mental disorders were clearly linked. People with depression were three-and-a-half-times more likely to sleepwalk than those without, and people with obsessive compulsive disorder were four times more likely. Alcohol dependence also was tied to nocturnal wandering.
Other factors, such as a lack of sleep, appeared to make a difference. People who got less than seven hours per night did have a higher risk of having at least one nocturnal wandering episode in the past year. One-third of individuals with a family history of sleepwalking experienced it themselves, although Ohayon said it was too soon to tell what the genetic connection might be.
When it comes to understanding underlying mechanisms and causality, the researcher stressed that there's a long way to go. "This is a cross-sectional study," he said. "So what I can see is the association. I cannot tell you the direction of the causality. It will be necessary to do a longitudinal study to do that."
But while such questions remain, treatment options exist. "A lot of people who experience parasomnias, experience them when they're under a lot of stress, so stress management can help," said Dr. Philip Gehrman, clinical director of the behavioral sleep medicine program the University of Pennsylvania, who was not associated with the new study.
He explained that medication can be a next step for some patients, although for many, simply knowing that sleepwalking is fairly common and relatively normal can be enough to put them and their bedmates at ease.
More serious consequences, while very rare, can occur. Last year, a New Jersey woman's drowning reportedly may have occurred when she fell into a lake after she walked out of her home while unconscious.
"If this is happening in a hotel, or not in your usual location, it could [result in] a big accident," Ohayon said. "These extreme cases must make us very cautious about sleepwalking. Happily, it's an exception that something like this happens."
Our 2024 Coverage Needs You
It's Another Trump-Biden Showdown — And We Need Your Help
The Future Of Democracy Is At Stake
Our 2024 Coverage Needs You
Your Loyalty Means The World To Us
As Americans head to the polls in 2024, the very future of our country is at stake. At HuffPost, we believe that a free press is critical to creating well-informed voters. That's why our journalism is free for everyone, even though other newsrooms retreat behind expensive paywalls.
Our journalists will continue to cover the twists and turns during this historic presidential election. With your help, we'll bring you hard-hitting investigations, well-researched analysis and timely takes you can't find elsewhere. Reporting in this current political climate is a responsibility we do not take lightly, and we thank you for your support.
Contribute as little as $2 to keep our news free for all.
Can't afford to donate? Support HuffPost by creating a free account and log in while you read.
The 2024 election is heating up, and women's rights, health care, voting rights, and the very future of democracy are all at stake. Donald Trump will face Joe Biden in the most consequential vote of our time. And HuffPost will be there, covering every twist and turn. America's future hangs in the balance. Would you consider contributing to support our journalism and keep it free for all during this critical season?
HuffPost believes news should be accessible to everyone, regardless of their ability to pay for it. We rely on readers like you to help fund our work. Any contribution you can make — even as little as $2 — goes directly toward supporting the impactful journalism that we will continue to produce this year. Thank you for being part of our story.
Can't afford to donate? Support HuffPost by creating a free account and log in while you read.
It's official: Donald Trump will face Joe Biden this fall in the presidential election. As we face the most consequential presidential election of our time, HuffPost is committed to bringing you up-to-date, accurate news about the 2024 race. While other outlets have retreated behind paywalls, you can trust our news will stay free.
But we can't do it without your help. Reader funding is one of the key ways we support our newsroom. Would you consider making a donation to help fund our news during this critical time? Your contributions are vital to supporting a free press.
Contribute as little as $2 to keep our journalism free and accessible to all.
Can't afford to donate? Support HuffPost by creating a free account and log in while you read.
As Americans head to the polls in 2024, the very future of our country is at stake. At HuffPost, we believe that a free press is critical to creating well-informed voters. That's why our journalism is free for everyone, even though other newsrooms retreat behind expensive paywalls.
Our journalists will continue to cover the twists and turns during this historic presidential election. With your help, we'll bring you hard-hitting investigations, well-researched analysis and timely takes you can't find elsewhere. Reporting in this current political climate is a responsibility we do not take lightly, and we thank you for your support.
Contribute as little as $2 to keep our news free for all.
Can't afford to donate? Support HuffPost by creating a free account and log in while you read.
Dear HuffPost Reader
Thank you for your past contribution to HuffPost. We are sincerely grateful for readers like you who help us ensure that we can keep our journalism free for everyone.
The stakes are high this year, and our 2024 coverage could use continued support. Would you consider becoming a regular HuffPost contributor?
Dear HuffPost Reader
Thank you for your past contribution to HuffPost. We are sincerely grateful for readers like you who help us ensure that we can keep our journalism free for everyone.
The stakes are high this year, and our 2024 coverage could use continued support. If circumstances have changed since you last contributed, we hope you'll consider contributing to HuffPost once more.
Support HuffPostAlready contributed? Log in to hide these messages.