On a May morning in 1987, just after 1:30 am, a 23-year-old Canadian named Kenneth Parks drove 14 miles to his stepfather’s house and strangled him. A year later, he was convicted but a thorough investigation brought to light the fact that Parks had actually had a sleepwalking episode during the murder.
This story inspired an American film titled “The Sleepwalker Killing.” The truth is that these cases are extreme but violence during sleepwalking episodes is not entirely strange. Therefore, although in the past I have already referred to the causes and consequences of sleepwalking , now I would like to return to its links with violence.
In 1995, a study carried out on 64 people who suffered from sleepwalking or night terrors showed that more than half of them exhibited violent behavior during the episodes. A subsequent analysis concluded that 70% of people who suffer from sleepwalking may act violently.
In fact, other epidemiological studies have confirmed that violence in people who suffer from sleepwalking is not a matter to be underestimated. In 2010, a study of more than 20,000 people from six European countries showed that 1.7% of them suffered from violent behavior during sleep. However, researchers think the figure could be even higher.
Obviously, the main problem lies in the lack of control of the person involved and their ability to carry out complex actions while asleep. Research carried out with functional resonance imaging has shown that this is due to the fact that during an episode of sleepwalking the areas of the prefrontal cortex (through which we regulate our decisions and behaviors) are inactive. However, areas involved in controlling movement, including the posterior cingulate cortex and some parts of the cerebellum, showed great activity.
However, these brain changes are not enough to explain violence. To be completely honest, science still does not have a definitive answer that explains this connection. Mark Pressman, a doctor at Thomas Jefferson University , analyzed 32 cases of nocturnal violence and realized that most of them were caused by encounters with other people during the sleepwalking episode.
It is also known that disruptive dreams are usually present in episodes of sleepwalking and could lead to violence since these people frequently report very vivid images that inspire fear. For this reason, many specialists hypothesize that people become violent since their brain perceives that it is being attacked.
Reference:
Siclari , F. ; Tononi , G. & Bassetti , C. (2012). American Mind ; July/August: 38-41.
