In the middle of the night, Corey Manchester walked up three flights of stairs from the basement, went into his stepmom's room and asked how Aunt Nikki was. A kid at the time, he wasn't satisfied until he heard Aunt Nikki was doing fine.
"There is no Aunt Nikki," Manchester, now 47, tells me from San Diego. "We don't have an Aunt Nikki in our family at all, on either side."
Manchester had been sleepwalking, and his stepmom was the first person to witness the behavior that's shadowed him the last several decades.
Manchester is one of about 3.6% of the population prone to sleepwalking. That figure is from a groundbreaking 2012 study out of Stanford University, which placed the number higher than previously thought. Until that research, it had been 30 years since researchers had published a prevalence rate of sleepwalking in the US, and there hasn't been an update since.
The sleep-related phenomenon, also called somnambulism, is part of a broader category of sleep disorders called parasomnias, which include behaviors like night terrors and sleep paralysis.
There's an inherent mystery to sleepwalking. Those who've experienced it might not even know they ever left their beds, if not for the accounts of the people they're with, or bits of evidence the next morning. (Who peed on the TV?) There is, perhaps, an unsettling disconnect between your body and consciousness, which are seemingly working apart from each other.
While this parasomnia isn't a mystery that's been fully unraveled, it's one that sleepwalkers and those who study them have been dealing with for years -- grappling with bodies that might walk themselves right into trouble, and how to get them safely back into bed.
In the span of a few weeks around 7th or 8th grade, Jen Bennet started sleepwalking. Her mother caught her rummaging through her bathroom drawers at night, walking down the stairs of their house -- eliciting alarm that her daughter might fall and hurt herself during one of her nighttime strolls.
"I woke up [one] day and I just had a Ziploc bag with Goldfish [crackers] in bed with me," the now-26-year-old Oakland, California, resident said.
Bennet's experience isn't unusual. In fact, sleepwalking is most common in children, and they tend to grow out of it by the time they reach their teens, said Raj Dasgupta, assistant professor of clinical medicine at Keck School of Medicine at the University of Southern California.
Dasgupta himself has an 8-year-old daughter who sleepwalks. He and his wife might be watching Cobra Kai on Netflix and see her walk into the kitchen. It makes sense -- sleepwalking most often happens during non-REM sleep, so early on in the sleep cycle. He'll redirect her to bed.
"I always ask her in the morning, 'Hey, do you remember walking into the kitchen?'" To which she'll reply, "'Nope, not at all.'"
That lack of memory is a key signature of parasomnias. What else is going on in the brain during a sleepwalking episode is also fuzzy.
One idea has been that sleepwalking occurs when areas of the brain associated with emotion and motor activity are awake while areas controlling memory and rationality aren't. Without the latter to keep the former in check, things can get messy.
The upshot: "Behavior is regulated by a kind of archaic survival system like the one that is activated during fight or flight," Lino Nobili, a sleep researcher at Niguarda Hospital in Milan, told Aeon.
A 2021 study from the University of Montreal and Montreal Sacred Heart Hospital, published in the journal Frontiers in Neurology, examined the roles that the sympathetic and parasympathetic nervous systems play in sleepwalking and found that perhaps that's not the case.
Instead of exhibiting an elevated fight-or-flight response, sleepwalkers in a sleep study showed more of a rest-and-digest response, which is how the body calms itself after danger has passed.
"While the causes of sleepwalking remain unclear, we know that while asleep, sleepwalkers can experience an abnormal interplay between processes linked to arousal and to deep sleep, even outside of their episodes," two of the authors wrote. In the relationship between arousal and poorly regulated deep sleep, perhaps something is going awry.
Why people sleepwalk
In 2001, Troy Maddox was approaching his final test to receive his black belt in kenpo karate. His instructor told him to visualize all the moves and techniques whenever he had a chance, be it in line at the grocery store or as he was drifting off to sleep.
So it's little wonder that one night, Maddox ended up in the middle of his bedroom, in a stance, fighting off attackers who didn't exist. It scared his then-wife, who woke up thinking someone had broken in.
"Once she knew that there was nobody in the house and that I was fighting thin air ... she hollered for me and got me to snap out of it enough that I just came back to bed. But I never even woke up," said the 51-year-old Louisville, Kentucky, resident.
Needless to say, Maddox decided to stop mentally practicing karate before bed.
Researchers generally have some ideas about what underlying causes might lead to sleepwalking. There appears to be some element of genetics at work -- those with parents and siblings with parasomnias are more likely to experience parasomnias themselves.
According to Alcibiades Rodriguez, clinical director of the Sleep Disorders Program at NYU Langone Health, sleep deprivation, anxiety, stress and the like have the potential to provoke sleepwalking in those who might be prone to it. Obstructive sleep apnea could be another underlying cause.
Sometimes, the act of sleepwalking in itself can generate anxiety.
"You start to sleepwalk and get very anxious -- the more anxious you get, the more sleepwalking you do, " Rodriguez said. "It turns into a vicious cycle."
Dasgupta also noted research that found that people with daytime sleepiness, fatigue, insomnia, depression and anxiety symptoms could be more likely to sleepwalk.
Other triggers could be problems with circadian rhythms, like serious jet lag. Emotional stress can be another trigger, as well as certain medications, like sleep aids, and particularly mixing them with alcohol, Dasgupta said.
Dealing with sleepwalking
Thiery Sparks remembers mornings as a kid when he woke up somewhere different in the house than where he went to sleep. His parents even told him they'd seen him up and around.
Now 30, Sparks, who lives in Salado, Texas, doesn't so much sleepwalk anymore as he occasionally finds himself having bolted halfway across the room after dreaming that there was something, like a raccoon, in his bed.
He estimates it happens maybe once every three months, that he remembers. It's never been enough of an issue that he considered going to a doctor.
For many sleepwalkers, this is the case. Dasgupta said that, for kids with classic sleepwalking, they lean on waiting until they grow out of it. Some adults participate in sleep studies. The point of a sleep study, though, isn't necessarily to catch an instance of sleepwalking. Rather, it's to figure out what the underlying causes may be. More rarely, a doctor might prescribe medication.
Sleepwalking can be dangerous if a person trips, falls or collides with something. It's not uncommon to run into scary headlines about people sleepwalking off cliffs while camping, or falling out of a window. There are potential bed partners to consider too, who might end up in the crosshairs of some sleepwalking activity.
And the conventional wisdom of not waking a sleepwalker holds true, Dasgupta said, mainly because it can cause anger, fear, confusion and disorientation. The best course of action is to try to steer them back to bed.
"I don't feel if I wake up my 8-year-old she's going to punch me in the face," Dasgupta said, "But ... it's not a pleasant feeling ... I wouldn't wake [sleepwalkers] up."
Back in San Diego, Manchester isn't exactly sure how often he sleepwalks. He lived by himself for about 12 years, so it's hard to say without a witness. He estimates that in the last five years it's happened twice.
"It's not [so] prevalent that I would warn someone if we went on a trip," he said.
Still, he's got a pile of stories to tell -- about the time his college roommate asked him what he was doing on the roof, or when he woke up in the car on the way to the airport with his cousin (she told him he'd been very grouchy before departing the house). Another time, a friend saw him calling for his dog Buddha when the pup was already sitting right next to him.
"To be told [about] those things that you have no connection with," Manchester said, "It's always been weird."