Sleep Violence Epidemiology in UK

The consequences for patients exhibiting Violent Behavior during Sleep range from benign acting out during sleep to self-mutilating injuries, murder or suicide. There are patients with Violent Behavior during Sleep who remain untreated for several years before seeking medical consultation and instead pursue idiosyncratic and often ineffective remedies to attempt to suppress their acting out behaviors.Until recently, a common assumption was that most acts of violence perpetrated during sleep were attributable to night terrors or sleepwalking episodes. In the eighties, Schenk et al. described a new syndrome, REM-sleep Behavior Disorder (RBD), characterized as "injuries or disruptive behaviors emerging during REM sleep, which ordinarily exhibits a generalized skeletal muscle atonia". In normal REM sleep, this protective measure of atonia was said to prevent the physical acting out of the dream but in subjects suffering from REM-sleep Behavior Disorder this atonia is absent, often resulting in injurious behavior to self or others (13, 14).Aggression associated with sleep was also reported in other types of sleep disorders but not as an essential diagnostic feature. Such was the case of somnambulism (3, 5, 6, 15, 16) and night terrors (15, 16), both parasomnias occurring during NREM sleep. Violent behavioral patterns might also occur in subjects suffering from nocturnal seizures (14, 16-19), in the transitional period between sleep and complete wakefulness (sleep drunkenness) (10, 20) or in some neurological diseases (21-23).

RESEARCH

We investigated the prevalence of violent or injurious behaviors occurring in sleep and the associated psychiatric risk factors in a representative UK sample of 2078 men and 2894 women. These individuals were between the ages of 15 to 100 (representing 79.8% of those contacted). They participated in a telephone interview directed by the Sleep-EVAL expert system specially designed for conducting such diagnostic telephone surveys.

RESULTS

Two percent (2.1%, n=106) of respondents reported currently experiencing violent or injurious behavior during sleep (VBS). The VBS group experienced more sleep terrors and daytime sleepiness than the non-VBS group. Sleep talking, bruxism, and hypnic jerks were more frequent within the VBS than the other group, as were hypnagogic hallucinations (especially the experience of being attacked), the incidence of smoking, caffeine and bedtime alcohol intake. The VBS group also reported current features of anxiety and mood disorders significantly more frequently, and reported being hospitalized more often during the previous 12 months, than the non-VBS group. Higher risks of reporting Violent Behavior during Sleep were found in subjects with mood or anxiety disorders only when co-occurring with other symptoms. We have showed a number of sleep, mental disorder and other general health factors that characterize those experiencing episodes of violent behavior during sleep.

THESE FINDINGS SUGGEST THAT SPECIFIC FACTORS, PERHAPS REFLECTING AN INTERACTION OF LIFESTYLE AND HEREDITARY CONTRIBUTIONS, MAY BE RESPONSIBLE FOR THE OBSERVED VARIABILITY IN THIS RARE BUT POTENTIALLY SERIOUS CONDITION.