April 26, 2012 by
Somnambulism, also known as sleepwalking, is thought to affect between 1% and 15% of the American population. The causes are cited to be anything from restless leg syndrome to mental illness, and the manifestations are even wider spread. There are some cases where people have been said to cook, eat, engage in sexual activity, and even murder…all in their sleep.
When we sleep, that sleep undergoes several stages. You have your NREM sleep, which is divided into stage 1, stage 2, and stage 3 and 4. Stage 1 is that light sleep, while stage 2 is a consolidated sleep period, stages 3 and 4 are deep sleep stages (known as “slow-wave sleep”), and after these stages we reach REM state. REM sleep (REM stands for Rapid Eye Movement) is where your eyes move rapidly under your eyelids, your respiration and heart rate can be irregular, and this is when you’re most likely to dream. Despite the rapid movement of the eyes, the respiration and heart rate irregularities, and the fact that your brain is possibly occupied by a dream, this is supposed to be our most restful stage of sleep, and it accounts for 90-120 minutes of a total night’s sleep. “Normal” sleepwalking occurs during the REM state, and if you do it you are considered to have a “REM State Sleeping Disorder.”
Sleepwalking can occur outside of the REM state, during stages 3 and 4 of NREM, during that deepest sleep. Specialists aren’t completely sure what causes the high-voltage delta waves that characterize sleepwalking. Some think it is a reactionary condition brought on by exhaustion, fever, or something similar. In some cases it is. In other cases, somnambulism occurs because of much deeper seated problem. For instance, many drug users are known to sleepwalk, and people with schizophrenia and anxiety disorders are more likely to be sleepwalkers. New research shows that sufferers of Tourette Syndrome and frequent migraine headaches are more prone to sleepwalk.
So, what of these people who claim to have had sex, cooked, sent email, and even murdered in their sleep. This is because, as we mentioned before, REM stage sleepwalking is one thing, but NREM sleepwalking is something else. During that stage 3 and 4 sleep, the brain is supposed to be, for lack of a better term, quiet. In a NREM state sleeping disorder, part of the brain wakes up, and causes the person to do all sorts of things. If that person is predisposed or in the “right” mindframe, they certainly can be capable of murder.
And, given that certain types of insomnia are considered a mental illness, they’ll probably get away with it.