Researchers at the University of California, observe abnormal behavior during sleep, such as walking, eating and even violence in many people. But a series of case reports shows that sleep disorders can also involve unconscious, sometimes aggressive, sexual behavior.
In a study of 10 patients with "atypical sexual behavior during sleep," researchers found that the patients' actions which ranged from "annoying" sexual moaning to actual sexual assault of a bed partner were related to several types of sleep disorders and, in many cases, psychiatric conditions.
In all cases, the researchers found evidence of a sleep disorder, and a majority of the patients had a history of sleep-related problems, including sleepwalking and night terrors. However the two patients whose sexual behavior during sleep was limited to loud moaning had no history of sleep disorders. For the other nine patients, abnormal sexual behavior ranged from violent masturbation to sexual assault of the bed partner while remaining asleep. Patients had no memory of the events after they awoke, and if awakened by their partners during an episode would appear confused and disoriented.
One 30 year-old man had sexually assaulted his partner between certain hours of the night for at least 6 years, according to the report. This patient had a family history of psychiatric illness, although he himself was not diagnosed with a mental disorder. The patient was treated for the sleep disorder REM behavior disorder.
Seven of the other patients were diagnosed with psychiatric conditions, including major depression, obsessive-compulsive disorder and anxiety. In some cases, patients had a history of sexual abuse. One man with a long history of sleep disturbances had been "very affected" by his father's revelation of his homosexuality, and the patient's own "strict religious convictions" had led him to abstain from sex and other behaviors he thought inappropriate, the researchers report.
The good news, according to Guilleminault's team, is that the abnormal sexual behavior was "eliminated" in most patients when their sleep disorders and psychiatric conditions were treated. It is unclear how common this sleep-related problem is, according the researchers, noting that it is "seldom reported in medicine."