Sleep sex, or sexsomnia, is a condition in which a person will engage in sexual activities while still asleep. This condition falls within the broad classes of sleep disorders known as parasomnia. In extreme cases sexsomnia has even been alleged as the cause of rare instances of sexual assault and rape. The proposed medical diagnosis is NREM arousal parasomnia – sexual behaviour in sleep. Sexsomnia is considered a type of non-rapid eye movement sleep (NREM) parasomnia. Sexsomniacs do not remember the acts that they perform while they are asleep. Sexsomnia can co-occur alongside other sleep disorders such as sleepwalking, sleep apnea, night terrors and bedwetting and can be triggered by stress, previous sleep deprivation and excessive consumption of alcohol or drugs.
Sleep related epilepsy may be associated with sexual arousal, pelvic thrusting and orgasms, though in these sorts of cases the acts are often not remembered.
Sexsomnia episodes could be triggered by physical contact with a bed partner. Sexsomnia, which is a fairly new medically recognized behaviour, has been used in criminal defense cases of rape. There have also been several cases of sexsomnia which have appeared in the news and also in pop culture as reality shows and movies.
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 (Colin Shapiro and Nik Trajanovic) and the University of Ottawa (Paul Fedoroff). The term “sleepsex” was used in a 1998 case report by David Saul Rosenfeld, a neurologist and sleep specialist from Los Angeles. The term ‘sexsomnia’ was coined by Colin Shapiro in a case report published in June 2003.