Certain drugs, sleep apnea and stress increase your risk.

Sleepwalking has long been thought to affect mainly children—and adults who do it often assume that their experience is rare. Now that assumption has been turned upside down.

Game-changing research: In a survey of more than 19,000 adults, nearly one-third of them reported that they had sleepwalked either as adults or children. But here’s where it gets really interesting—3.6% of adults surveyed (which would represent roughly 8.4 million American adults in the general population) had done it at least once in the previous year…and 1% reported two or more episodes a month.

What happens: Most people who sleepwalk do it intermittently—say, once every few weeks. Some take multiple walks on a single night—wandering for a few minutes and going back to bed repeatedly.

Other sleepwalkers engage in routine activities, such as cooking meals or doing small chores around the house.

To learn more about the surprising causes of sleepwalking and how to best treat it, Bottom Line/Health spoke with Shelby Harris, PsyD, a leading specialist in sleep disorders.

WHAT CAUSES IT

Contrary to popular belief, dreaming has nothing to do with sleepwalking. In fact, your skeletal muscles are essentially paralyzed during rapid eye movement (REM) sleep, the stage during which dreams most often occur.

People typically sleepwalk during slow-wave sleep. This phase of deep sleep occurs at intervals throughout the night but predominates during the first third of your sleep time. Everyone has brief awakenings in the transitions between sleep stages. Sleepwalking usually happens during these moments of arousal.

Anything that disturbs deep sleep can lead to awakenings that are associated with sleepwalking. What’s been linked to sleepwalking…

Depression. People with depression are 3.5 times more likely to sleepwalk than those without it.

Use of antidepressants or sleeping pills. Selective serotonin reuptake inhibitor (SSRI) antidepressants, such as sertraline (Zoloft) and paroxetine (Paxil), and prescription sleeping pills, such as zolpidem (Ambien), increase risk for sleepwalking. Over-the-counter sleep aids such as Benadryl also increase risk.

Sleep-disturbing conditions. This can include sleep apnea (interrupted breathing during sleep), anxiety and emotional stress.

WHAT HAPPENS DURING SLEEPWALKING?

Most individuals who sleepwalk don’t know that they’ve done so unless someone tells them. During sleepwalking, the sleepwalker’s conscious brain is essentially shut off and he/she has limited awareness. Sleepwalkers tend to engage automatically in activities that are routinely done and are often clumsy in their movements.

If you live alone, you might suspect that something’s amiss if you feel fatigued after what you thought was a good night’s sleep. You might also notice that books or other objects aren’t where you left them. I have talked to people who cook (messily) in their sleep…use a hair dryer…or even run a bath.

DO YOU NEED TREATMENT?

Occasional episodes of sleepwalking are unlikely to be a problem as long as you’re not tripping, falling down stairs, walking into (or through) glass doors, leaving your house or otherwise endangering yourself. If you sleepwalk, do all that you can to keep your environment safe—for example, remove clutter from your floors and use an alarm system or locks. Some sleepwalkers may be able to turn off an alarm or open a lock, but the precaution will likely alert others if you don’t live alone.

If you’re not able to take steps to ensure your safety, see a sleep specialist to make sure that you’re practicing good sleep habits and to rule out medical and psychiatric issues that may be contributing to your sleepwalking.*

WHAT CAN YOU DO?

Because sleepwalking has been strongly linked to sleep deprivation, it’s crucial for sleepwalkers to take steps that allow them to get enough sleep. Sleepwalking episodes might stop once an underlying sleep problem (such as those described earlier) is treated. My ­advice…

Don’t use sleeping pills. Because sleepwalking is a side effect of some newer sleep medications, such as Ambien, this type of drug should be avoided if it is resulting in this problem.

Better approach: The most effective ways to improve sleep naturally include getting exercise during the day (ideally four to six hours before bedtime)…going to bed and getting up at the same times every day…not watching TV or working on a computer in the bedroom…avoiding caffeine within six hours of bedtime…and using heavy curtains or a sleep mask to block out light.

Try cognitive behavior therapy (CBT). If you need even more help improving your sleep, try CBT. This type of therapy helps you change beliefs and behaviors that interfere with your ability to get enough sleep. Research has found CBT to be just as effective as sleep medications. Improvement usually occurs within six sessions. The cost of CBT for sleep issues is often covered by insurance.

Focusing on good sleep habits and adding CBT, if needed, usually improves sleep significantly. If this does not occur, consult your doctor about short-term use of a sedative, such as clonazepam (Klonopin).

HOW TO HELP A SLEEPWALKER

Don’t try to awaken a person who is sleepwalking. Trying to engage a sleepwalker in conversation or otherwise awaken him/her can prolong or worsen the episode.

Best approach: Gently guide the sleepwalker back to bed while calmly and softly saying something like, “It’s bedtime.” The sleepwalker will usually do what you’re asking.

*To find a sleep specialist, consult the American Academy of Sleep Medicine, AASMnet.org.