Carlos H. Schenck, MD
The term “parasomnia” refers to all the abnormal things that can happen to people while they sleep, apart from sleep apnea . Some examples are sleep-related eating disorder, sleepwalking, nightmares, sleep paralysis, REM sleep behavior disorder, and sleep aggression. Sexsomnia, sometimes called “sleepsex,” is also a parasomnia. It refers to sexual acts that are carried out by a person who is sleeping. Parasomnias can have negative effects on people during the daytime, including sleepiness.
Parasomnias can occur as a person is falling asleep or at any point in the sleep cycle. If they occur while falling asleep, a person may experience disturbing hallucinations or sleep paralysis, which is when the body is unable to move for seconds or minutes. Sleep paralysis can be quite frightening, especially when it occurs with hallucinations.
Parasomnias that occur during sleep, such as REM sleep behavior disorder (RBD), often involve vigorous and harmful dream-enacting behaviors. RBD is a brain disorder that usually occurs in men over 50 years of age, but can affect people of any age who are taking certain medications, such as antidepressants, and people with neurologic disorders, such as Parkinson's disease, narcolepsy or stroke. Other parasomnias that occur during sleep include nightmares and sleep-related groaning, which can be loud and prevent a person's bed partner or roommate from sleeping.
In addition, there are parasomnias that occur when a person has abrupt, partial awakenings, such as confusional arousals, sleepwalking, sleep terrors, and sleep-related eating disorder.
Sleep-related hallucinations may also occur as a person is waking up.
Parasomnias often run in families and so there is probably a genetic factor in many cases. Brain disorders may be responsible for some parasomnias, such as many cases of REM sleep behavior disorder. Parasomnias may also be triggered by other sleep disorders such as obstructive sleep apnea, and by various medications.
Parasomnias affect approximately 10% of Americans. They occur in people of all ages, but are more common in children. Children are particularly