Sleep sex or sexsomnia is a form of non-rapid eye movement (NREM) parasomnia (similar to sleepwalking) that causes people to engage in sexual acts while they are asleep. The proposed medical diagnosis is NREM Arousal Parasomnia - Sexual Behaviour in Sleep, and is considered to be a distinct variant of sleepwalking/confusional arousals (ICSD 2).
The first research paper that suggested that sexual behavior during sleep may be a new type of parasomnia was published in 1996 by three researchers from the University of Toronto (Dr. Colin Shapiro and Dr. Nik Trajanovic) and the University of Ottawa (Dr. Paul Fedoroff) . Later, several papers were published describing the problem and suggested that problematic forms of sleep sex are medically treatable "conditions" (see external links). The condition was defined in a paper called "Sexsomnia — A New Parasomnia?" published in the Canadian Journal of Psychiatry in June 2003. The first doctor to coin the term "Sleep sex" was Dr. David Saul Rosenfeld, a neurologist and sleep doctor from Los Angeles, California.
In some cases, sufferers are aware of their behavior for a long time before they seek help, often because they lack information that it is a medical disorder or for fear that others will judge it as willful behavior rather than a medical condition. However, the reality of sexsomnia has been confirmed by sleep disorder researchers who have made polygraphic and video recordings of patients with the condition while they are asleep and observed unusual brain wave activity during the episodes similar to that experienced in other NREM arousal parasomnias. It is a mind/body disconnect that occurs during sleep. The treatment has commonalities with other NREM parasomnias, and also involves specific interventions. By avoiding precipitating factors and ensuring a safe environment, the condition could be brought to a high level of control with minimal effort.
Sexsomnia is not always problematic or extreme for those who experience it or for their partners. There is a great variety in both the frequency and levels to which people are affected by this disorder.