What Causes Sleep Violence?
When it comes to aggressive sleepers, the stakes are high.
Over the years, I’ve treated a number of patients with violent and dangerous parasomnias. In all of these cases, the stakes are especially high. Not only is my patient’s sleep and health compromised, but their safety—and the safety of other people, especially those closest to them—is very much at risk.
Sleep forensics is a branch of sleep medicine that investigates and seeks to understand violent, strange, and irrational behavior related to sleep. These investigations are necessary when sleep issues may be related to crimes. But sleep forensics also helps us better understand the phenomenon of sleep violence, even when the behavior isn’t criminal.
I think it’s important to understand that sleep violence exists and how it can occur. Incidents of sleep violence happen more often than many people realize. Violence during sleep isn’t common, but it’s also not extremely rare. Estimates indicate that approximately 1.7 to 2 percent of the population experiences some form of sleep-related violent behavior.
What causes sleep violence?
Several factors in a person’s life can elevate their risks for sleep-related violence. These include:
• History of parasomnia (sleepwalking, sleep talking, etc.)
• Stress and psychological conditions
• Alcohol and drug use (especially within a few hours of bed)
• Medication interactions
• Lack of sleep
• Physical and mental health conditions, including epilepsy, neurodegenerative disease such as Parkinson’s and some forms of dementia, and dissociative disorders such as PTSD
Often, it’s a cluster of these risk factors together that creates the conditions for sleep violence in a person’s life.
The sleeping mind is an active mind
It’s easy to think of sleep as a time when the “off” switch has been flipped in the brain. Without waking consciousness and memory, the hours you spend sleeping can seem like lost time. But in truth, the brain and body are active throughout every stage of sleep—growing and repairing cells and tissues, rebooting the immune and metabolic systems, restoring organ function, processing memory, emotion, and recent learning.
Sleep isn’t a void of consciousness. Rather, it involves a different form of consciousness—or being—with different brain activity (I’m talking about dreams here). The main states of sleep consciousness are REM sleep and non-REM, or NREM, sleep. Each has patterns of brain activity that are distinct from one another and distinct from waking consciousness. (This is how we classify sleep stages, based on the different brain waves.)
Many parasomnias, including those that can put a sleeper at risk for sleep-related violence, occur as a person moves between NREM, REM, and wakefulness.
Patients and families who are coping with violent and disruptive sleep behaviors ask me, how is it possible for a sleeper to act out so intensely while still asleep? Understanding sleep as an active state of being, rather than a pause button, is one important step in understanding how these behaviors can come about.