Some would be surprised to hear that sleepwalking, otherwise known as somnambulism, is actually considered a behavioral disorder of sleep (Britannica, 2021). In the DSM-5, it is classified as a parasomnia, a category of sleep disorders characterized by atypical behavior and behavioral and psychological events that intrude on sleep. Other examples of parasomnias include night terrors and sleep paralysis (Mash, 2019).
One common misconception about sleepwalking is that it happens while dreaming. The rapid eye movement (REM) stage of sleep is when we have the most vivid dreams, but our bodies are actually paralyzed even though our eyes continue to move. Studies in rats have pinpointed the neurotransmitters GABA and glycine as key components for maintaining muscle paralysis due to their inhibitory effects on motor neurons (ScienceDaily, 2012). The proper functioning of these pathways protects us from injury because, without them, we would act out our dreams. This paralysis makes sleepwalking during REM sleep impossible.
Somnambulism is considered a non-rapid eye movement (NREM) sleep arousal disorder that happens during N3, a deep state of sleep. This stage usually lasts for about thirty minutes during the first third of the night and is marked by high amplitude, low-frequency delta waves in the brain, indicative of slow, synchronous activity. Once someone enters this deep sleep it can be difficult to wake them up, and since there is no mechanism for maintaining paralysis, movement is possible (Healthwise, 2020).
To learn more about somnambulism and examine some other misconceptions, let’s look at a firsthand account of a sleepwalking experience:
I was 12 years old on vacation with my family. With all my other sleepwalking stories I have no recollection of them, but this one I do. Basically, I wasn’t awake but I was conscious. I ‘woke up’ thinking that I had to leave the hotel ASAP. The weird thing was that this was the only thought in my mind. I could see where I was going but I couldn’t think about anything other than that. I got up, walked to the door, and left the room. I looked down the hallway. Across from our room there was a spiral staircase that connected the first floor to the second. I walked over, looked down at the lobby and saw that no one was there. I was confused and I realized I had to go back to the room. For some reason I thought my sister would open the door, so I knocked on the door and kept knocking until my dad opened it. I don’t remember going to bed afterwards. (Anonymous)
Eight years after the incident, this girl could still remember what happened, proving that contrary to popular belief, sleepwalkers can retain some recollection of their sleepwalking adventures although it is a rare occurrence in children. Another surprising detail was that her behavior was directed and not random, but this is also normal. In Dr. Antonio Zadra’s sleepwalking study published in The Lancet Neurology, the same pattern was observed. Although the reasoning behind this is poorly understood, of the sleepwalkers that remembered their episodes, most could explain the reasons for their actions. The doctor discovered, “They are the first to say, once awake, that their explanations are nonsensical. However, during the episode, there is an underlying rationale” (Sleepwalkers, 2021). In other words, their motives aren’t driven by logic.
While the fact that the girl felt as if she needed to escape her hotel “ASAP” is nonsensical and makes for an amusing story, this emphasizes just how dangerous sleepwalking can be. This story could have ended very differently if the girl had wandered farther from her family, as there’s no telling who she could have encountered. Even if there was no one around during the episode, it put her at risk for injury, as such cognitive impairment puts individuals at a risk for tripping, stepping on things, or falling. Because attacks usually subside during adolescence and adulthood, people can get the impression that there is no risk associated with somnambulism. However, with 15% of children ages 4 to 12 experiencing at least one attack in their lifetimes, and 1% to 6% having weekly episodes, it’s important for parents to be aware of consequences and triggers (Mash, 2019).
It’s interesting to note that this took place on a family vacation, as travel and a disrupted sleep schedule are known triggers for sleepwalking episodes. Others include stress, fever, and sleep deprivation as well as underlying conditions like substance abuse, restless leg syndrome, sleep apnea, and gastroesophageal reflux disease (Mayo Foundation, 2017). Awareness of these triggers can better equip parents to ensure the safety of their children.
References
Encyclopaedia Britannica (2021). Sleepwalking. Encyclopedia Britannica. https://www.britannica.com/science/sleepwalking
Healthwise staff. Stages of sleep. Michigan Medicine. (2020). https://www.uofmhealth.org/health-library/hw48331
Mash, E. J., & Wolfe, D. A. (2019). Abnormal child psychology. Cengage Learning.
Mayo Foundation for Medical Education and Research. (2017). Sleepwalking. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/sleepwalking/symptoms-causes/syc-20353506
ScienceDaily. (2012). How muscles are paralyzed during sleep: Finding may suggest new treatments for sleep disorders. ScienceDaily. https://www.sciencedaily.com/releases/2012/07/120711131030.htm
Sleepwalkers sometimes remember their actions. Sleep Education. (2021). https://sleepeducation.org/sleepwalkers-sometimes-remember-their-actions/
