When People Kill in Their Sleep
Some bad dreams can turn deadly.
Kenneth Parks, who in 1987 was acquitted of murder because he was asleep at the time. Image: Frank Lennon/Toronto Star/Getty
One night in 1950, Ivy Cogdon lay awake in bed, too anxious to sleep. The Korean War was in its early days and she worried the conflict would find its way to Australian shores. That night, her fears were realized. From her bed, she saw a group of North Korean soldiers surrounding her family home in the suburbs of Melbourne. She rushed to her 19-year-old daughter's room. A soldier was on the bed, attacking her only child. Mrs. Cogdon dashed outside to the wood heap, grabbed an axe and returned to her daughter's room. She attacked the North Korean, delivering two heavy blows to the back of his head.
And then, in a "Dallas" twist, Mrs. Cogdon woke up.
There wasn't a soldier in sight. The North Korean invasion was all a dream. But her actions were real. Mrs. Cogdon stood at her daughter's bed, bloodied axe in hand. She had killed her own child.
At trial, Mrs. Cogdon was found not guilty of murder. The jury was satisfied that she suffered extreme sleepwalking and had no mental or emotional control over her actions at the time.
Dr. Michel Cramer Bornemann is a sleep expert who reviews criminal cases of violence by sleeping defendants. He said that abnormal sleep behaviors, from walking and talking to murder and sexual assault, are known as parasomnias. To explain parasomnias, Dr. Cramer Bornemann first explained how we sleep: The brain transitions between four key stages of sleep in a sleep cycle. In a typical 8 hour sleep period, an individual usually goes through 6-8 sleep cycles.
"The brain has to coordinate very highly synchronized connectivity between different parts of the brain in order to engage in all of those stages of sleep in a fluid fashion," he said. "We have to keep in mind that the brain is made of 86 billion neurons… we have to think about the brain as a complex electrical network of connectivity between various anatomical sub-units."
Most people's brains manage to pull off the switches between sleep stages seamlessly. But for people who suffer from parasomnias, a "switching error" causes an incomplete transition between the stages.
"Instead of having a fully declared state of non-REM or REM, you have a combination of non-REM and REM, or between non-REM and wakefulness, or between REM and wakefulness," Dr. Cramer Bornemann said. "These periods can be very short in duration but they are very unstable."
The overlaps between REM sleep and wakefulness, and between non-REM sleep and wakefulness, are where dangerous behaviors like Mrs. Cogdon's usually occur. In those two states, a person is asleep and awake at the same time, but the potential dangerous behavior is different depending on the two combinations.
During REM sleep, the limbic system, which is the part of the brain responsible for emotions and mood, is highly active. That's why dreams can be really weird and intense. Usually during REM sleep, our muscle movement is paralyzed, and that paralysis is a vital safeguard to stop us from acting out our crazy dream lives.
But a if a switching error occurs between REM sleep and wakefulness, the overlap with wakefulness can negate that paralysis. The safeguard is down, and the sleeper now has the motor skills to run outside to grab an axe—or even to get dressed, drive 14 miles through Toronto to their in-laws house and strangle, bludgeon and stab his victims, as in the case of Kenneth Parks—all while partially asleep.
For those caught in a switching error between non-REM and wakefulness, the story is a little different. This combination covers your garden variety sleepwalking. The sleeper is awake enough to engage in automatic behavior, like walking, talking, or eating, but they're not awake enough to be highly aware of their surroundings. It's a precarious state and if the sleeper is suddenly aroused, they might not be able to distinguish between a gentle shake asking them to wake up, and an attack. So, for example, if a porter tries to wake a man who has drifted off in a hotel lobby, the sleeper may respond to what he perceives as an attack by pulling his gun and shooting the porter three times.
Dr. Cramer Bornemann said the majority of criminal matters he deals with arise from sudden arousals like these. He said the violence is usually aimed towards someone close to the sleeper and there are some frightening examples to back that up: in one case, a man woke to a sudden noise and shot his girlfriend, thinking he was defending himself from an intruder; in another, a father beat his 18-month-old son to death, thinking he was fending off a beast that was attacking the child.
Dr. Cramer Bornemann emphasizes, and courts accept, that people who exhibit violence during parasomnia are not behaving with full awareness or intent. But while intent is relevant in the courtroom, it probably doesn't matter to the person on the receiving end of the axe.
So how can you tell whether you're sharing your home with a could-be sleeping killer?
First of all, watch out for Damien. About 12-18 percent of children sleepwalk, compared to 4 percent of adults. Dr. Cramer Bornemann says the higher rate in children is reflective of the fact that the brain is still maturing and forming those electrical connections that allow smooth switches between the stages of sleep. People who sleepwalked as children are also more likely to experience parasomnias as adults.
Dr. Cramer Bornemann has a top tip to navigate the danger of sleeping with a sleepwalker: "If you encounter someone who is sleepwalking, try to direct them in a gentle manner back to sleep. If you abruptly try to push someone who is sleepwalking it can trigger a primal response of defensive posturing which can be very violent – then can strike out, lash out, even grab something nearby such as a knife…They'll strike out not knowing who they are attacking because it's a primal behavior."
For anyone predisposed to parasomnias, certain influences can enhance the frequency or intensity of episodes. The main risk factors are sleep deprivation, stress, and anxiety.
For example, Mrs. Cogdon was found to suffer from "a form of hysteria" and her waking stresses had a habit of feeding into her dreams. After hearing that a house nearby bred spiders as a hobby (which is enough to give anyone nightmares), Mrs. Cogdon dreamed her home was infested with them. She woke that night to find herself aggressively brushing dreamed spiders from her daughter's face.
On the night she killed her daughter, the two discussed the war in Korea, which was a real concern to Mrs. Cogdon. Before saying goodnight, Mrs. Cogdon's daughter told her not to worry, "It's not on our front door step yet." Seed: planted.
Certain substances can also make matters worse, including the stuff that's meant to aid sleep. Dr. Cramer Bornemann warns, "Sleeping pills are associated with ultra levels of consciousness and awakeness. I have over 300 criminal cases looking at sleep disorders and violence and one third of those criminal cases involve Ambien or sleeping pills."
So if the warning signs are there for you or your bed buddy, avoid sleep deprivation, stress and sleeping pills and remove war and violence from your pillow talk repertoire. Definitely don't let the sleepwalker sleep with a pistol under the pillow and, if all else fails, lock the bedroom door.
All in Your Head is a series that takes a scientific look at all things spooky and scary. Follow along here.