Sleep-related violence

Scientific Advances

Gregory B. Leong MD and J. Arturo Silva MD

Sleep-related violence has traditionally been considered a rare problem. However, a recent survey by Ohayon and associates suggests that although the problem is not common, it still appears to be more widespread than originally thought.¹ The concurrent recording of brain electrical activity and physiologic functions has been the mainstay of sleep studies during the past four decades of solid scientific research on sleep and dreaming. Despite the available means to study sleep-associated violence, it has only recently received significant attention. This recent work delving into the interconnections between sleep and violence may be of great relevance to the practice of forensic psychiatry.^2-4

For the purposes of this column, we define sleep-induced violence as aggressive behavior arising out of disturbance or dysfunction during the sleep state that results in the physical harm of people or destruction of objects in the physical environment. There are two primary states of human consciousness, sleep and wakefulness. The sleep state can be further divided into rapid eye movement (REM) and non-REM states.

The recent attempts to develop a classification scheme of sleep-associated violence underscores the embryonic nature of research into sleep-associated violence.^5,6 For example, Mahowald and colleagues have classified sleep-associated violence into the following categories: 1) night terrors and sleepwalking; 2) nocturnal seizures; 3) sleep drunkenness; 4) psychogenic dissociative states; and 5) REM sleep-behavior disorder.⁶ Of these five types, REM sleep-behavior disorder (RBD) represents a relatively new addition to the violence associated sleep states. In RBD the affected person may manifest REM period violence that is related to dream enactment .^6,7

The other four types have a longer history, two of which will be mentioned here. There are well-documented causes of sleep-related violence due to night terrors and sleep walking, hypothesized to be linked to incomplete arousal from non-REM sleep.⁸ Possible etiologies are pharmacologic, including prescribed medications, alcohol, and other recreational drugs,^8,9 as well as psychosocial stress. ² Sleepwalking behavior that has been associated with violence may respond to anticonvulsant medication.⁶

Sleep drunkenness can occur during the transition between sleep and wakefulness.^5,6 It is characterized as "a disturbance of consciousness occurring on sudden arousal from sleep, characterized by confusion, disorientation and a misinterpretation of reality." ⁵ Such loss of reality testing can lead to serious aggression, including homicidal behavior.

Competent evaluation of sleep-related violence should start with a sophisticated level of expertise in the technical aspects of sleep medicine.^6,10 Because sleep disorders are likely to be influenced by psychosocial factors in varying degrees, a comprehensive forensic psychiatric assessment of an individual with a sleep disorder and violence should follow a biopsychosocial-legal approach. In particular, questions of criminal responsibility, including insanity or unconsciousness, may hinge on the complex interplay between a sleep disorder and violent behavior.