Yun Kwok Wing, MD, PhD
Chinese University of Hong Kong, China
Automatic behaviors during sleep (ABS) mostly refer to parasomnia characterized by sleep-related movements or behaviors, such as confusional arousal, sleepwalking, and sleep-related eating disorder (SRED).
There are several case reports on ABS among psychiatric patients. Warnings have been added for the use of psychotropics, especially hypno-sedatives, regarding on their risk of potential effect on ABS. However, most of the published evidences were case reports or series with limited data on the clinical epidemiology of ABS. Given the potential serious outcome such as sleep-related injuries among subjects with ABS, its prevalence and associated risk factors have to be investigated further. Two recent clinical epidemiological studies in psychiatric populations reported that the prevalence of ABS ranged from 4.0% to 15% [1,2]. Various risk factors, including co-morbid sleep disturbances, and use of psychotropics were associated with ABS .
Sleepwalking, one of the common ABS encountered in psychiatric patients, was found to have more adult onset, diverse clinical features, and associated with high prevalence of sleep-related injuries in psychiatric patients .
SRED was also found to be prevalent among patients of mental illnesses. Among various associated factors, SRED has the strongest association with the regular use of zolpidem, a non-benzodiazepine hypnotics . One out of seven subjects taking zolpidem could develop SRED symptoms, and most of the subjects were taking therapeutic dosage regularly . The precipitating role of zolpidem was further strengthened by a follow-up open interventional study that cessation of zolpidem could result in immediate and sustained disappearance of SRED .
Although the exact reason on the susceptibility of psychiatric patients towards ABS remains elucidated, current findings suggested that the aetiologies are likely to be complex and multifactorial. Personal vulnerability, predisposing effect of co-morbid sleep disturbances, stress, psychopathologies, and the use of psychotropics, could have joint effect in contributing to the occurrence of ABS in psychiatric populations .
- Lam SP, Fong SYY, Ho CKW, et al. Parasomnia among psychiatric outpatients: a clinical, epidemiologic, cross-sectional survey. J Clin Psychiatry 2008; 69: 1374- 1382.
- Hwang TJ, Ni HC, Chen HC, Lin YT, Liao SC. Risk predictors for hypnosedative-related complex sleep behaviors: a retrospective, cross-sectional pilot study. Clin J Psychiatry 2010; 71: 1331-1335
- Lam SP, Fong SYY, Yu MWM, Li SX, Wing YK. Sleepwalking in psychiatric patients: a comparison of childhood and adult onset. Aust N Z J Psychiatry 2009; 43:428-32.
- Wing YK, Lam SP, Li SX, Zhang J, Yu MWM. Sleep-related eating disorder and zolpidem- an open interventional cohort study. J Clin Psychiatry 2010; 71(5):653- 656.
Mark W. Mahowald, MD
University of Minnesota
Increasingly, sleep medicine specialists are asked to render opinions regarding legal issues pertaining to violent or injurious behaviors purported to have arisen from sleep.
Sleep is no longer considered to be simply the passive absence of wakefulness. Sleep is an active, rather than passive process, and is not a unitary, whole brain phenomenon. The declaration of state is not necessarily "all or none", and there may be incomplete declaration or rapid oscillation of the three states of being. The complex behaviors arising from these mixed states of being may result in violent or injurious behaviors.
Disorders of arousal are the most common causes of sleep-related violence and occur on a broad spectrum ranging from confusional arousals (also termed sleep drunkenness) to sleepwalking (SW) to sleep terrors (ST). Although there is usually amnesia for the event, vivid dream-like mentation may occasionally be experienced and reported. Contrary to popular opinion, these disorders may actually begin in adulthood, and are most often not associated with significant psychopathology.
The fact that SW or ST can be triggered by environmental stimuli speak against their being the culmination of ongoing psychologically significant sleep mentation. This is further supported by the fact that these events, when recorded polygraphically, are infrequently preceded by either sleep/EEG changes or by acceleration of heart rate - reflecting their truly precipitous nature. The pathophysiology of DOA is incompletely understood, however, central pattern generators, state, and sleep inertia provide much insight.
More research, both basic science and clinical, is urgently needed to further identify and elaborate upon the components of both waking and sleep-related violence, with particular emphasis upon neurobiologic, neuroplastic, genetic, and socioenvironmental factors.
The study of violence and aggression will be greatly enhanced by close cooperation among clinicians, basic science researchers, social scientists, and legal scholars.
Andrew Krystal, MD, MSc
Duke University, Durham
A number of reports link hypnotic medications to parasomnias such as somnambulism, confusional arousals, and sleep eating. However, little systematic research has been carried out to determine if the risks of these events are increased as a result of taking hypnotic medications. In this work, we review recent findings on the epidemiology of these types of parasomnias including the risks associated with hypnotic medications. These data are then contextualized in terms of clinical experience with hypnotics, small studies reporting a link between non-REM parasomnias and particular hypnotic medications, and data from all of the available placebo-controlled trials of hypnotic medications. We then discuss the implications of the new epidemiologic data for:
- Clinical practice,
- Regulatory agencies, and