NREM parasomnias result from an incomplete arousal from the deepest stage of sleep (for this reason, they are also called “disorders of arousal”), which predominantly takes place during the first half of the night [4]. NREM parasomnias are thought to be caused by increased sleep inertia impairing normal arousal mechanisms and/or sleep fragmentation (related to noise, pain, or comorbid disorders as detailed below). They occur more frequently in children and can persist during adulthood, whereas adult onset is less common and is often secondary to an underlying sleep, medical, or psychiatric disorder or due to sedative medications. The NREM parasomnias can be placed on a continuum of increasing behavioral activity dominated by confusion, limited response to environmental stimuli, and subsequent amnesia, which can have medicolegal implications when leading to violent behaviors involving bed partners, household members, or other individuals within proximity to the patient [5, 6]. Electroencephalogram (EEG) recording during the events often reveals maintenance of delta slow-wave activity characteristic of NREM sleep or the simultaneous presence of slow and faster alpha frequencies (only seen during wakefulness and REM sleep) in different subsets of brain structures. In addition to a family history of NREM parasomnias, risk factors include hypnotic use (typically the benzodiazepine receptor modulators), sleep deprivation resulting in deepened sleep or sudden forced awakening, disruption of circadian rhythm, or any conditions fragmenting sleep, such as obstructive sleep apnea (OSA), restless leg syndrome (RLS) in the case of sleepwalking, narcolepsy, as well as physical or emotional stress [1, 7–11]. In most cases, the diagnosis is based on history and can be supported by a video recording of the event. However an in-lab overnight study with video polysomnography (PSG) utilizing expanded electromyography (EMG) montage and sometimes EEG is indicated in atypical, refractory, or severe cases, as well as de novo forms in adults. Such a study allows for distinguishing NREM parasomnias from other conditions manifesting with abnormal nocturnal agitation, such as RBD or NFLE. It should also be performed when a concomitant sleep disorder is suspected. NREM parasomnias are generally benign and when occurring in children, usually remit by later adolescent years. Management should include reassurance, environmental changes to minimize risks of injury, avoidance of triggering factors, and treatment of any associated sleep disorders that could contribute to sleep fragmentation [11] (Table 13.2). Family or roommates should be discouraged from waking up the individual during an episode, as this is generally counterproductive and may aggravate confusion and agitation [6]. Psychotherapy is only indicated when an underlying psychopathology is suspected. Although its efficacy is inconsistent, pharmacotherapy is indicated in most violent cases. Although they can contribute to the emergence of NREM parasomnias, longer-acting benzodiazepines such as clonazepam can be used to decrease sleep fragmentation. Various antidepressant medications have also been used but have limited efficacy (Table 13.2).