Parasomnias

When the transition from one sleep state to another doesn't progress in an orderly fashion or a person is aroused from sleep, bizarre and often complex behaviors known as parasomnias may occur. Parasomnias include sleepwalking, night terrors, and bedwetting, which are NREM disorders that occur early in the night. Night terrors are characterized by agitation, large pupils, sweating, and increased blood pressure. Many of the parasomnias are more common in children, who usually outgrow them and don't require treatment. Superficially resembling night terrors but more common in adults is REM sleep behavior disorder, which is characterized by vigorous or violent behaviors that occur later in the night. In this disorder, the temporary muscle paralysis that normally characterizes REM sleep is absent, allowing individuals to react to vivid dreams during sleep and potentially injure themselves or their bed partners. This disorder usually affects middle aged or elderly individuals who frequently also have a neurological disorder. Fortunately, most of these parasomnias can be treated effectively.

A relative of the NREM parasomnias is sleep-related eating disorder, in which a person eats food during the night while he or she appears to be asleep. Two-thirds of patients with this disorder are women. It may be induced by taking certain medications, such as amitriptyline (a sedating antidepressant) or zolpidem (a hypnotic), but it also may be triggered by other sleep disorders, such as obstructive sleep apnea or restless legs syndrome. Although many medicines have been tried to treat the disorder, their success has been limited.