Imagine yourself getting up in the middle of the night, raping your wife violently, and never remembering what it is you actually did. It may sound like it could never happen to you, but it can.
"Sleep sex" is a term coined by US scientists to describe a particular sleep disorders phenomenon, which can cause people to commit sexual acts on themselves or their partners - while asleep.
The condition can range in severity from disruptive moaning to unwanted, and sometimes violent, sexual advances to their partner.
But no matter how serious their night-time behaviour, patients did not remember what they had done the next morning. The Stanford scientists, whose research is published in the journal Psychosomatic Medicine, believe the condition is caused by a sleep disorder combined with emotional problems.
Sleep sex is much like sleepwalking, but much, much worse. Sleepwalking ... takes place just before deep REM sleep, and the person who experiences it won’t remember what they have done if they are never woken up afterwards. These unfortunate people are unable to wake from their sleep unless something happens that doesn’t mesh with what is happening in their dreams.
For instance, a man beating his wife in his dreams wouldn’t wake up to the sound of her screams because she would be screaming in his dreams as well. He might wake up if she started to speak soothingly to him, because this wouldn’t mesh with the reality he is experiencing within his dreams.
Cases have been reported of husbands killing their wives, raping them, masturbating so violently that they wake up with bruises and wives who have sex with total strangers, all while being totally asleep.
Christian Guilleminault, professor of psychiatry and behavioural sciences at the Stanford School of Medicine, studied 11 patients, grouping them according to the seriousness of their symptoms.
In all cases except one, the patient's disorder was cured by sleep disorder treatments including drugs similar to Valium and treatments used for breathing disturbances.