In the silent film "The Cabinet of Dr. Caligari," a deranged hypnotist controls a sleepwalker, using him to commit crimes. Obviously, this 1920 film isn't an accurate depiction of somnambulism, but even a century after the film's release, this sleep disorder still isn't particularly well understood. We don't even know what causes it.

Indeed, there's probably more fiction than fact surrounding sleepwalking, and knowing so little about it only adds to the disorder's mystique.

Still, there are things we do know, and that knowledge can help to dispel some of the mystery around sleepwalking.

1. Sleepwalkers can perform a range of activities. One thing that we tend to understand about sleepwalking, especially given that it's right there in the name, is that people will walk or even perform some activities while they're asleep. These activities, according to the U.K.'s National Health Service (NHS), can range from simply walking around the house to getting dressed or even eating. More severe cases can involve complex tasks, like driving a car.

2. Sleepwalking mostly occurs during one stage in the sleep cycle. Sleep is divided into stages, and our bodies behave differently in each one. Sleepwalking occurs in stage three of non-rapid eye movement sleep or non-REM sleep. During this stage, our brains produce more delta waves, resulting in a period of deep sleep from which it is difficult to wake the sleeper. In addition to sleepwalking, night terrors are also likely to occur during this stage. If sleepwalking happens during REM sleep, it may be a sign of a much more serious sleep disorder called REM sleep behavior disorder and it can be associated with neurological conditions like Parkinson's disease.

Sleepwalking boy holds pillow close to his chest Sleepwalkers are more likely to be children or young teens than adults. (Photo: Africa Studio/Shutterstock)

3. Most sleepwalkers are children and young teens. Sleepwalking occurs in children and young teens more than in adults for the simple reason that adults experience less stage three sleep than children do. Researchers aren't sure why that happens. Sleepwalking can still occur in adults; it's just less common.

4. Sleepwalking might be hereditary. There's evidence to suggest that sleepwalking runs in the family. A 2014 study in JAMA Pediatrics looked at 1,940 children born between 1997 and 1998, following their sleep habits from March 1999 to March 2011. Thirty percent of the children in the study reported sleepwalking. If one parent was a sleepwalker, the child was three times more likely to also sleepwalk, and if both parents were sleepwalkers, the child was seven times more likely to be a sleepwalker.

5. Sleepwalking has other signs. In addition to walking or dressing while they're asleep, sleepwalkers may show some of the following symptoms, according to the U.S. National Library of Medicine:

  • Eyes open while asleep
  • Blank facial expression
  • Not remembering sleepwalking when waking
  • Confusion or disorientation upon waking
  • Potentially aggressive behavior if someone wakes them

A woman yawns while in bed Guiding a sleepwalker to bed is perhaps the best way to get them back to sleep. (Photo: Nitikorn Poonsiri/Shutterstock)

6. Waking a sleepwalker won't kill them. Perhaps the biggest myth about sleepwalking is that waking a sleepwalker is dangerous for their health. "You can startle sleepwalkers, and they can be very disoriented when you wake them up and they can have violent, or confused reactions, but I have not heard of a documented case of someone dying from being woken up," Michael Salemi, general manager at the California Center for Sleep Disorders, told Scientific American in 2007. Experts generally recommend gently guiding a sleepwalking person back to bed.

7. Sleepwalking lacks treatment options. There are no specific treatments for sleepwalking because it doesn't typically require any. Short-acting tranquilizers may be prescribed to reduce how often it happens, but lifestyle changes can help. Developing a regular sleep routine, avoiding caffeinated beverages and relaxing before sleep often can solve the problem with the need for medication.

7 myth-busting facts about sleepwalking
Sleepwalking is a misunderstood sleep disorder that's buried in more myths than facts.