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Sleep Sex or Sexsomnia


What is Sleep Sex?

Sleep sex, also called sexsomnia, refers to a sleep disorder where an individual who is asleep initiates sexual activity, either on their own or with a partner present.

Sexsomnia is considered a sub-category of parasomnia, sleep disorders that include sleep talking, walking, eating, as well as sleep violence. Only recently have researchers documented enough cases of sleep sex to propose that it be considered a unique diagnosis of sleep disorder.

Sleep sex encompasses a range of sexual behaviors, including (but probably not limited to):

While there are too few documented cases for researchers to describe sleep sex conclusively, the current understanding is that in cases of genuine sexsomnia, the behaviors are "involuntary" in that the sleeping person initiating them is unaware they are happening, and often has no memory of them occurring when confronted at a later point with the behavior. In several case studies, partners who are sexually acted upon describe having to shake or slap their partner to wake them up, at which point they appear disoriented and confused.

In some cases the partner reports that the sexual behavior during sleep is significantly different from the sexual behavior while awake (and in two cases I read, the sleep sex was preferred).

Alarmingly, sexsomnia is increasingly being cited in cases of sexual assault as a possible defense. With so little known about sleep sex, researchers and clinicians have expressed concern about the legal implications of a term that has no clear diagnosis.

How Common Is Sleep Sex?

There isn’t enough research to establish how common sleep sex is definitively. Researchers who have studied multiple cases of sleep sex suggest that it is likely more common than we know, as they have routinely found people reticent to talk about their sleep sex behaviors until directly asked about it. Since most physicians do not ask about sleep sex, we probably have no sense of the prevalence in the general population.

A 2010 review of the charts of 832 sleep clinic patients found that 7.6% responded yes when asked if they had ever initiated sexual activity with a partner while asleep, but the majority of patients never discussed this with a doctor unless they were asked about it.

Another 2010 survey of 1,000 adults in Norway reported that 7.1% of people experienced "sexual acts during sleep" at least once in their lives, and 2.7% reported it occurring once in the past 3 months.

Sleep sex seems to be more common among men, although there are reported cases of women initiating sexual behaviors while sleeping. In a review of 32 cases of sleep disorders with sexual behavior, 80% of the cases involved men and 20% women. In the more recent review of 832 patients, 11% of those reporting sleep sex symptoms were men, while 4% were women.


The causes of sleep sex, and even what physiological and neurological mechanisms underlie it are still being explored. Many people who are found to engage in sleep sex have other sleep disorders. Some of them also have substance abuse issues and other psychological issues. It seems likely that there is not one kind of sleep sex, and not one single cause for the condition.

Connections Between Sleep Sex and Sexual Assault

Some of the earliest cases of sleep sex came to the attention of clinicians in the context of court cases where an individual was arrested for sexual assault and claimed to have been asleep and have no memory of committing a sexual assault.

Several of the case studies of sleep sex include information about charges being laid, and individuals have been acquitted when such evidence has been presented. In cases where evidence of sleep disorder is presented, it is usually diagnosed by detailed observations during sleep.

In some ways, it's troubling that a disorder which is so newly described could be used (possibly illegitimately) by people who commit sexual assaults. Yet there seems to be agreement on the part of sleep researchers that sleep sex represents a real disorder which involves essentially involuntary sexual initiation.

A large review of sleep sex cases and research included a recommendation that individuals diagnosed with this disorder who have been arrested and acquitted on sexual assault charges resulting from sleep sex be informed that they cannot in the future use sleep sex as a defense.

Hopefully more research will provide ways of further diagnosing people with sleep sex disorders, and ensure that the disorder is not used as an alibi, and people with the disorder are given proper access to treatment and prevention methods.


Bjorvatn, B., Gronli, J., Pallesen, S. "Prevalence of Different Parasomnias in the General Population" Sleep Medicine Vol. 11 (2010): 1031-1034.

Cramer Bornemann, M.A. "Sexsomnia: A Medicolegal Case-Based Approach in Analyzing Potential Sleep-Related Abnormal Sexual Behaviors" in Parasomnias: Clinical Characteristics and Treatment (eds.) Sanjeev V. Kothare and Anna Ivanenko. Springer, 2013.

Ebrahim, I.O. “Somnambulistic Sexual Behaviour (Sexsomnia).” Journal of Clinical Forensic Medicine Volume 13, No. 4 (2006): 219-224.

Schenk, C.H., Arnulf, I., & Mahowald, M.W. “Sleep and Sex: What Can Go Wrong? A Review of the Literature on Sleep Related Disorders and Abnormal Sexual Behaviors and Experiences.” Sleep Volume 30, No. 6 (2007): 683-702.

Shapiro, C.M., Trajanovic, N.N., & Fedoroff, J.P. “Sexsomnia - A new parasomnia?” Canadian Journal of Psychiatry Volume 48, No. 5 (2003): 311-317.

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