Sexual behavior while sleeping is more common than previously thought, according to a study by the Sleep Research Laboratory at the University Health Network’s Toronto Western Hospital. Of the 832 sleep disorder sufferers who participated in the study, 7.6% reported incidents of initiating or partaking in sexual activity while asleep. Dr. Colin Shapiro, head of Neuropsychiatry and the Sleep and Alertness Clinic at the hospital, invented the term “sexsomnia” to describe a particular form of the rare condition parasomnia, which involves unusual behaviour—such as sex—during sleep. Parasomniacs may complain about poor-quality sleep, but have no memory of walking, talking, eating or having sex while sleeping. The paper, presented today at the annual meeting of the Associated Professional Sleep Societies in San Antonio, also notes that those who reported sexsomnia were twice as likely as the others to use illegal drugs, and more men than women suffer from sexsomnia (about 11 per cent versus four per cent).