Sex with strangers

Another case reported by New Scientist magazine involved a middle-aged Australian woman who left her house and had sexual intercourse with strangers over several months.
Circumstantial evidence, such as condoms found scattered around the house, alerted the couple to the problem. On one occasion, her partner awoke to find her missing, went searching for her and found her engaged in the sex act.

"Incredulity is the leading player in cases like this," says Dr Peter Buchanan, the sleep physician at the Woolcock Institute of Medical Research in Sydney, who handled the case.
But a combination of factors convinced him that the case was a real sleepwalking phenomenon, including the distress of the couple and an in-depth clinical evaluation.

 There are a number of examples in the research literature describing men having intercourse with their partners while asleep. Usually the women describe the man as being "glassy-eyed" and vacant. The behaviour stops if he is awakened.

Such behaviour seem to happen most often in people with other significant sleep-related problems, such as sleepwalking or driving and eating while asleep.

Other factors that may increase the risk of sexsomnia include the use of alcohol or sleep disruption caused by obstructive sleep apnea and sleep deprivation. But there are also detractors.