Parasomnias are defined as abnormal movements or behaviors that occur in sleep or during arousals from sleep. Parasomnias vary in frequency from episodic events that arise from incomplete sleep state transition. The framework by which parasomnias are categorized and diagnosed is based on the International Classification of Sleep Disorders-Third Edition, Text Revision (ICSD-3-TR), published by the American Academy of Sleep Medicine. The recent Third Edition, Text Revision (ICSD-3-TR) of the ICSD provides an expert consensus of the diagnostic requirements for sleep disorders, including parasomnias, based on an extensive review of the current literature.

Nocturnal agitation refers to a broad spectrum of symptoms from simple movements to aggressive behaviors with partial or complete loss of awareness. An accurate identification of its etiology is critical for appropriate therapeutic intervention. In children and young adults, distinguishing between non-rapid eye movement (NREM) sleep parasomnias and psychogenic non-parasomniac manifestations, a condition known as sleep-related dissociative disorder (SRDD), can be challenging. This review aims to summarize current clinical, neurophysiological, and epidemiological knowledge on NREM parasomnia and SRDD, and to present the pathophysiological hypotheses underlying these nocturnal manifestations. Sleepwalking, sleep terror and confusional arousals are the three main presentations of NREM parasomnias and share common clinical characteristics. Parasomniac episodes generally occur 30minutes to three hours after sleep-onset, they are usually short, lasting no more than few minutes and involve non-stereotyped, clumsy behaviors with frequent amnesia. The prevalence of NREM parasomnia decreases from 15-30% in children to 2-4% in adults. Parasomniac episodes are incomplete awakening from the deepest NREM sleep and are characterized by a dissociated brain activity, with a wake-like activation in motor and limbic structures and a preserved sleep in the fronto-parietal regions. SRDD is a less known condition characterized by dramatic, often very long episodes with frequent aggressive and potentially dangerous behaviors. SRDD episodes frequently occur in quiet wakefulness before falling asleep. These dissociative manifestations are frequently observed in the context of psychological trauma. The pathophysiology of SRDD is poorly understood but could involve transient changes in brain connectivity due to labile sleep-wake boundaries in predisposed individuals. We hypothesize that SRDD and NREM parasomnia are forms of sleep-related dissociative states favored by a sleep-wake state dissociation during sleep-onset and awakening process, respectively.

To update the literature on the diagnostic category of sleep-related dissociative disorders (SRDDs), involving psychogenic dissociation, since the time of their inclusion in the parasomnias section of the International Classification of Sleep Disorders, second edition, in 2005; to summarize the most salient clinical and video-polysomnographic (vPSG) findings and typical clinical profile from all reported cases; and to provide the rationale for the re-inclusion of the group of SRDDs in future editions of the International Classification of Sleep Disorders.
A systematic computerized literature search was conducted searching for SRDDs, nocturnal dissociative disorders, and nocturnal dissociation.
Nine additional cases were identified, with sufficient clinical history and vPSG findings to justify the diagnosis of SRDDs, supplementing the 11 cases cited in the International Classification of Sleep Disorders, second edition, for a total of 20 cases. Twenty-six other cases with vPSG testing were found, with 18 cases reported in abstracts and 8 cases reported in a publication with compelling histories of SRDDs and 2 consecutive vPSG studies, but without the vPSG findings explicitly reported for any case. In more than half of all reported cases, there was objective diagnostic confirmation for SRDDs consisting of the hallmark finding of abnormal nocturnal behaviors arising from sustained electroencephalography wakefulness, or during wake-sleep transitions, without epileptiform activity. These nocturnal behaviors often replicated daytime psychogenic dissociative behaviors. A history of trauma (physical, sexual, emotional) was an almost universal finding, along with major psychopathology. All patients, except for one, had prominent histories of daytime dissociative disorders. Many of the patients were referred on account of a presumed parasomnia.
Cases of SRDDs continue to be reported, often as a \"parasomnia mimic,\" with psychogenic dissociation being clearly distinguished from physiologic sleep-wake dissociation as found in primary sleep disorders such as narcolepsy, rapid eye movement sleep behavior disorder, etc. Eleven reasons are provided for why the category of SRDDs should be re-included in future editions of the International Classification of Sleep Disorders, and in the parasomnias section.

Parasomnias are involuntary behaviors or subjective experiences during sleep. Our objective was to review existing information on the presence of parasomnias in patients with addictions or during treatment for addictions. Information about parasomnias related to rapid-eye-movement (REM) and non-REM sleep in patients with addictions, while using substances or in abstinence, was reviewed. A systematic search of published articles reporting parasomnias as a consequence of drug use or abuse was conducted in the PubMed and SciELO databases. The search for the studies was performed in three phases: (1) by title, (2) by abstract, and (3) by complete text. The search was performed independently by two researchers, who then compared their results from each screening phase. Seventeen articles were found. The consumption of alcohol was reported in association with arousal disorders, such as sexsomnia and sleep-related eating disorder; and REM sleep behavior disorder was reported during alcohol withdrawal. Cocaine abuse was associated with REM sleep behavior disorder with drug consumption dream content. Overall, we found that several types of parasomnias were very frequent in patients with addictions. To avoid accidents in bedroom, legal problems, and improve evolution and prognosis; must be mandatory to include security measures related to sleep period; avoid pharmacological therapy described as potential trigger factor; improve sleep hygiene; and give pharmacological and behavioral treatments for patients with these comorbid sleep disorders.

There exists a varying level of evidence linking the use of antidepressant medication to the parasomnias, ranging from larger, more comprehensive studies in the area of REM sleep behavior disorder to primarily case reports in the NREM parasomnias. As such, practice guidelines are lacking regarding specific direction to the clinician who may be faced with a patient who has developed a parasomnia that appears to be temporally related to use of an antidepressant. In general, knowledge of the mechanisms of action of the medications, particularly with regard to the impact on sleep architecture, can provide some guidance. There is a potential for selective serotonin reuptake inhibitors, tricyclic antidepressants, and serotonin-norepinephrine reuptake inhibitors to suppress REM, as well as the anticholinergic properties of the individual drugs to further disturb normal sleep architecture.