Parasomnias involve automatic behavior, i.e., seemingly goal-directed, complex purposeful behaviors enacted without the conscious awareness and volition of the individual, who cannot exercise conscious deliberate control over his or her behaviors and sleep-related experiences. It could be subdivided by taking into account the motoric versus autonomic/ sensory activation. This chapter deals with the most common disorders, covering the appropriate diagnostic and therapeutic strategies. Disorders of arousal include sleepwalking or somnambulism, sleep terrors, and confusional arousals. The pathophysiology of REM sleep behavior disorder (RBD) lies in a dysfunction of the brainstem structures modulating REM sleep. Enuresis consists of recurrent involuntary urination during sleep. It includes primary forms, where bladder control has never been achieved, and secondary variants occurring after a period of bladder control. Catathrenia, also known as nocturnal groaning or expiratory vocalization during sleep, consists of the emission of an unusual expiratory noise occurring in bursts without associated motor phenomena.

The sleep disorders that predispose to trauma are: disorders associated with excessive daytime sleepiness, obstructive sleep apnea, upper airway resistance syndrome, periodic limb movement disorder, narcolepsy, cataplexy, sleep paralysis and hypnagogic hallucinations. The disorders associated with behaviors while asleep (parasomnias) are: sleep terrors and sleepwalking and REM sleep behavior disorder. Injury can result from behaviors that occur during sleep. The patient's ability to recall the episode depends partly on the type of the parasomnia (occurrence during non-REM versus REM sleep). The other sleep disorders are recurrent hypersomnia and insomnia. Insomnia can result from multiple causes including psychiatric or general medical disorders, medication effects, substance abuse, and other sleep disorders. Restless legs syndrome (RLS) is another important cause of insomnia. RLS is thought to be related to periodic limb movement disorder and is characterized by lower extremity dysesthesias that occur at rest.