Associate News Editor
Reviewed by John M. Grohol, Psy.D. on May 15, 2012
About 1.1 million adults in the U.S. — or 3.6 percent of the nation’s adult population — are prone to sleepwalking, according to new research from the Stanford University School of Medicine. The research also showed an association between sleepwalking and psychiatric disorders, such as depression and anxiety.
The study “underscores that fact that sleepwalking is much more prevalent in adults than previously appreciated,” noted Maurice Ohayon, M.D., D.Sc., Ph.D., professor of psychiatry and behavioral sciences, who is the lead author of the paper. It will appear in the May 15 issue of Neurology, the medical journal of the American Academy of Neurology.
Sleepwalking, a disorder “of arousal from non-REM sleep,” can have serious consequences, resulting in injuries to the sleepwalker or others, as well as impaired psychosocial functioning, the researchers noted.
It is thought that the use of medication and certain psychological and psychiatric conditions can trigger sleepwalking, but the exact causes are unknown, the researchers added. Also unknown to experts in the field: its prevalence.
“Apart from a study we did 10 years ago in the European general population, where we reported a prevalence of 2 percent of sleepwalking, there are nearly no data regarding the prevalence of nocturnal wanderings in the adult general population,” the researchers said in their published paper. “In the United States, the only prevalence rate was published 30 years ago.”
The latest study was the first to use a large, representative sample of the U.S. population to demonstrate the number of sleepwalkers, according to the researchers, who also aimed to evaluate the importance of medication use and mental disorders associated with sleepwalking. Ohayon and his colleagues secured a sample of 19,136 individuals from 15 states and then used phone surveys to gather information on mental health, medical history, and medication use.
Participants were asked specific questions related to sleepwalking, including frequency of episodes during sleep, duration of the sleep disorder, and any inappropriate or potentially dangerous behaviors during sleep. Those who didn’t report any episodes in the last year were asked if they had sleepwalked during their childhood. Participants were also asked whether there was a family history of sleepwalking and whether they had other symptoms, such as sleep terrors and violent behaviors during sleep.
The researchers determined that as many as 3.6 percent of the sample reported at least one episode of sleepwalking in the previous year, with 1 percent saying they had two or more episodes in a month. Because of the number of respondents who reported having episodes during childhood or adolescence, lifetime prevalence of sleepwalking was found to be 29.2 percent.
The study also showed that people with depression were 3.5 times more likely to sleepwalk than those without, and people dependent on alcohol or who had obsessive-compulsive disorder were also significantly more likely to have sleepwalking episodes. Additionally, people taking SSRI antidepressants were three times more likely to sleepwalk twice a month or more than those who didn’t.
“There is no doubt an association between nocturnal wanderings and certain conditions, but we don’t know the direction of the causality,” said Ohayon. “Are the medical conditions provoking sleepwalking, or is it vice versa? Or perhaps it’s the treatment that is responsible.”
Although more research is needed, the work could help raise awareness of this association among primary care physicians, he added. “We’re not expecting them to diagnose sleepwalking, but they might detect symptoms that could be indices of sleepwalking,” said Ohayon.
Among the researchers’ other findings:
- The duration of sleepwalking was mostly chronic, with just over 80 percent of those who have sleepwalked reporting they’ve done so for more than five years.
- Sleepwalking was not associated with gender and seemed to decrease with age.
- Nearly one-third of individuals with nocturnal wandering had a family history of the disorder.
- People using over-the-counter sleeping pills had a higher likelihood of reporting sleepwalking episodes at least two times per month.