Study of the different sleep disturbances during the prodromal phase of depression and mania in bipolar disorders.

BACKGROUND: One of the challenges in bipolar disorder (BD) lies in early detection of the illness and its recurrences, to improve prognosis. Sleep disturbances (SD) have been proposed as reliable predictive markers of conversion. While preliminary studies have explored the relationship between SD and the onset of mood episodes, the results remain heterogeneous and a few have specifically examined patients' perception of prodromal symptoms and their progression until the episode occurs. Identifying prodromes represents a crucial clinical challenge, as it enables early intervention, thereby reducing the severity of BD. Therefore, the objective of this study is to better characterize and evaluate the progressive nature of SD as prodromal symptoms of mood episodes, and patients' perception of it. METHODS: Patients diagnosed with BD, either hospitalized or seeking treatment for a (hypo)manic or depressive episode benefited from standardized questionnaires, structured interviews, and self-report questionnaires to evaluate SD prior to the current episode, as well as sociodemographic and clinical information. RESULTS: Out of the 41 patients included, 59% spontaneously reported SD prior to the episode, appearing 90 days before depression and 35 days before mania (pre-indexed/spontaneous reports: 51.22% insomnia complaints, 4.88% hypersomnolence complaints, 7.32% parasomnias, 2.44% sleep movements). After inquiry about specific SD, the percentage of patients reporting prodromal SD increased significantly to 83%, appearing 210 days before depression and 112.5 days before mania (post-indexed reports: 75.61% presented with insomnia complaints appearing 150 days before depression and 20 days before mania, 46.34% had hypersomnolence complaints appearing 60 days before depression, 43.9% had parasomnias appearing 210 days before depression and 22.5 days before mania, 36.59% had sleep movements appearing 120 days before depression and 150 days before mania). Of note, bruxism appeared in 35% of patients before mania, and restless legs syndrome in 20% of patients before depression. CONCLUSION: This study highlights the very high prevalence of SD prior to a mood episode in patients with BD with differences between depressive and manic episodes. The more systematic screening of sleep alterations of the prodromal phase improved the recognition and characterization of different symptoms onset by patients. This underscores the need for precise questioning regarding sleep patterns in patients, to better identify the moment of transition toward a mood episode, referred to as "Chronos syndrome". The study emphasizes the importance of educating patients about the disorder and its sleep prodromal symptoms to facilitate early intervention and prevent recurrences.

Trajectory of maternal depression and parasomnias.

Maternal depressive symptoms are associated with poorer sleep quality in their children. Although parasomnias can occur at any age, this group of sleep disorders is more common in children. The aim of this study was to assess whether maternal depression trajectories predict parasomnias at the age of 11 years. Data were from a Birth Cohort of 4231 individuals followed in the city of Pelotas, Brazil. Maternal depressive symptoms were assessed with the Edinburgh Postnatal Depression Scale (EPDS) at 12, 24, and 48 months, and 6 and 11 years postpartum. Maternal depression trajectories were calculated using a group-based modelling approach. Information on any parasomnias (confused arousals, sleepwalking, night terrors, and nightmares) was provided by the mother. Five trajectories of maternal depressive symptoms were identified: chronic-low (34.9%), chronic-moderate (41.4%), increasing (10.3%), decreasing (8.9%), and chronic-high (4.4%). The prevalence of any parasomnia at the age of 11 years was 16.8% (95% confidence interval [CI] 15.6%-18.1%). Confusional arousal was the most prevalent type of parasomnia (14.5%) and varied from 8.7% to 14.7%, 22.9%, 20.3%, and 27.5% among children of mothers at chronic-low, moderate-low, increasing, decreasing, and chronic-high trajectories, respectively (p < 0.001). Compared to children from mothers in the chronic-low trajectory, the adjusted prevalence ratio for any parasomnia was 1.58 (95% CI 1.29-1.94), 2.34 (95% CI 1.83-2.98), 2.15 (95% CI 1.65-2.81), and 3.07 (95% CI 2.31-4.07) among those from mothers in the moderate-low, increasing, decreasing, and chronic-high trajectory groups, respectively (p < 0.001). In conclusion, parasomnias were more prevalent among children of mothers with chronic symptoms of depression.

Consciousness in non-REM-parasomnia episodes.

Sleepwalking and related parasomnias are thought to result from incomplete awakenings out of non-rapid eye movement (non-REM) sleep. Non-REM parasomnia behaviours have been described as unconscious and automatic, or related to vivid, dream-like conscious experiences. Similarly, some observations have suggested that patients are unresponsive during episodes, while others that they can interact with their surroundings. To better grasp and characterise the full spectrum of consciousness and environmental (dis)connection associated with behavioural episodes, 35 adult patients with non-REM sleep parasomnias were interviewed in-depth about their experiences. The level of consciousness during parasomnia episodes was reported to be variable both within and between individuals, ranging from minimal or absent consciousness and largely automatic behaviours (frequently/always present in 36% of patients) to preserved conscious experiences characterised by delusional thinking to varying degrees of specificity (65%), often about impending danger, variably formed, uni- or multisensory hallucinations (53%), impaired insight (77%), negative emotions (75%), and variable, but often pronounced, amnesia (30%). Patients described their experiences as a dream scene during which they felt awake ("awake dreaming"). The surroundings were either realistically perceived, misinterpreted (in the form of perceptual illusions or misidentifications of people), or entirely hallucinated as a function of the prevailing delusion. These observations suggest that the level of consciousness, amnesia and sensory disconnection during non-REM parasomnia episodes is variable and graded. In their full-fledged expression, non-REM parasomnia experiences feature several core features of dreams. They therefore represent a valuable model for the study of consciousness, sleep-related sensory disconnection and dreaming.

Insomnia and parasomnia induced by validated smoking cessation pharmacotherapies and electronic cigarettes: a network meta-analysis.

We aim to assess the relationship between validated smoking cessation pharmacotherapies and electronic cigarettes (e-cigarettes) and insomnia and parasomnia using a systematic review and a network meta-analysis. A systematic search was performed until August 2022 in the following databases: PUBMED, COCHRANE, CLINICALTRIAL. Randomized controlled studies against placebo or validated therapeutic smoking cessation methods and e-cigarettes in adult smokers without unstable or psychiatric comorbidity were included. The primary outcome was the presence of "insomnia" and "parasomnia." A total of 1261 studies were selected. Thirty-seven studies were included in the quantitative analysis (34 for insomnia and 23 for parasomnia). The reported interventions were varenicline (23 studies), nicotine replacement therapy (NRT, 10 studies), bupropion (15 studies). No studies on e-cigarettes were included. Bayesian analyses found that insomnia and parasomnia are more frequent with smoking cessation therapies than placebo except for bupropion. Insomnia was less frequent with nicotine substitutes but more frequent with bupropion than the over pharmacotherapies. Parasomnia are less frequent with bupropion but more frequent with varenicline than the over pharmacotherapies. Validated smoking cessation pharmacotherapies can induce sleep disturbances with different degrees of frequency. Our network meta-analysis shows a more favorable profile of nicotine substitutes for insomnia and bupropion for parasomnia. It seems essential to systematize the assessment of sleep disturbances in the initiation of smoking cessation treatment. This could help professionals to personalize the choice of treatment according to sleep parameters of each patient. Considering co-addictions, broadening the populations studied and standardizing the measurement are additional avenues for future research.

Pattern of sleep disorders among children with autism spectrum disorder.

BACKGROUND: Sleep disorders (SDs) are among many co-morbid medical conditions that affect children with autism spectrum disorder (ASD). Raising awareness and improving the standard of care for children diagnosed with ASD may result from identifying SDs among them. This study aims to evaluate patterns of SDs among Sudanese children diagnosed with ASD. METHOD: Using the Childhood Sleep Habit Questionnaire (CSHQ) to gather data on sleep disorders and SPSS version 26.0 for data analysis, a descriptive cross-sectional study was carried out in the five main autistic centres in Khartoum state covering all registered patients with ASD between April and June 2022. Ninety-two children diagnosed with ASD were enrolled in this study after the purpose of the research was explained and consent was obtained from their guardians. A p-value < 0.05 was considered to indicate statistical significance. RESULTS: The mean age was 6.90 (± 2.6) years with a boys-to-girls ratio of 2.17:1. The prevalence of SDs (at least one sleep condition almost daily) was 95.65%. Sleep onset 71 (77.2%), limit setting 32 (32.6%), resistant onset to sleep 48 (52.2%), and combined 52 (56.5%) insomnia affected the majority of children. Additionally, there were significant associations between sex and Limit-setting insomnia, advanced sleep phase disorder, and narcolepsy type 2 (P values = 0.033, 0.009, and 0.037, respectively). Additionally, there was a significant association between age and sleep-related breathing disorders-snoring (p value = 0.031). CONCLUSION: The frequency of SDs is significant among children diagnosed with ASD from Sudan, and certain SDs are associated with age and sex. Subsequent studies are required to develop national guidelines for the prevalence, presentation, screening, and treatment of SDs in children diagnosed with ASD.

Fever-induced acute sleep terrors in children and adolescents following SARS-CoV-2 infection.

OBJECTIVE: This study aims to provide physicians with insights into the clinical manifestations and outcomes of children and young adolescents experiencing sleep terrors following SARS-CoV-2 infection. METHODS: We enrolled patients who developed new onset sleep terrors after SARS-CoV-2infection fromDecember2022to April 2023 in the Xijing hospital, Xi'an, China. RESULTS: We enrolled six patients who experienced sleep terrors following SARS-CoV-2 infection. Out of these patients, five were children and only one was an adolescent, with a mean age of 9 years. Neuroimaging results were negative for all cases. Sleep terrors occurred during both the active course of COVID-19 illness and the recovery period in all patients. Symptoms included crying or screaming in terror, hyperactivity, inappropriate behavior and periods of mental confusion during sleep. These episodes typically occurred 40 min to 1 h after falling asleep. EEG monitoring confirmed two patients' episodes occurred during non-rapid eye movement (NREM) stage 3 sleep. The duration of sleep terrors ranged from 3mines to30 mines, with each patient experiencing 3-4 to 30-40 instances. Initially, the frequency of episodes was highest at 3-4 times per night, gradually decreasing to once a night, then once a week, until complete disappearance. No medical intervention was required. Clinical follow-up ranged from 6 to 12 months, with spontaneous remission occurring within 1 week to 2 months for different patients. CONCLUSION: SARS-CoV-2 infection may precipitate acute sleep terrors in children and adolescents. The course of these sleep terrors is generally benign, with all patients achieving spontaneous complete remission over time.

The associations between paranormal beliefs and sleep variables.

Previous studies have found significant associations between paranormal beliefs and sleep variables. However, these have been conducted on a small scale and are limited in the number of sleep variables investigated. This study aims to fill a gap in the literature by investigating paranormal beliefs in relation to a wide range of sleep variables in a large sample. Participants (N = 8853) completed a survey initiated by the BBC Focus Magazine. They reported on their demographics, sleep disturbances and paranormal beliefs. Poorer subjective sleep quality (lower sleep efficiency, longer sleep latency, shorter sleep duration and increased insomnia symptoms) was associated with greater endorsement of belief in: (1) the soul living on after death; (2) the existence of ghosts; (3) demons; (4) an ability for some people to communicate with the dead; (5) near-death experiences are evidence for life after death; and (6) aliens have visited earth. In addition, episodes of exploding head syndrome and isolated sleep paralysis were associated with the belief that aliens have visited earth. Isolated sleep paralysis was also associated with the belief that near-death experiences are evidence for life after death. Findings obtained here indicate that there are associations between beliefs in the paranormal and various sleep variables. This information could potentially better equip us to support sleep via psychoeducation. Mechanisms underlying these associations are likely complex, and need to be further explored to fully understand why people sometimes report "things that go bump in the night".

Sleep and epilepsy: A clinical and pathophysiological overview.

The interaction between sleep and epilepsy is complex. A better understanding of the mechanisms linking sleep and epilepsy appears increasingly important as it may improve diagnosis and therapeutic strategies in patients with epilepsy. In this narrative review, we aim to (i) provide an overview of the physiological and pathophysiological processes linking sleep and epilepsy; (ii) present common sleep disorders in patients with epilepsy; (iii) discuss how sleep and sleep disorders should be considered in new therapeutic approaches to epilepsy such as neurostimulation; and (iv) present the overall nocturnal manifestations and differential diagnosis between epileptic seizures and parasomnia.

Rapid eye movement sleep behaviour disorder: Past, present, and future.

This manuscript presents an overview of REM sleep behaviour disorder (RBD) with a special focus on European contributions. After an introduction examining the history of the disorder, we address the pathophysiological and clinical aspects, as well as the diagnostic issues. Further, implications of RBD diagnosis and biomarkers are discussed. Contributions of European researchers to this field are highlighted.

Risk factors of sleep paralysis in a population of Polish students.

BACKGROUND: Sleep paralysis (SP) is a transitional dissociative state associated with the REM sleep phase that affects approximately 28.3% of the student population during their lifetime. The reasons for the high prevalence of SP in the student population are not entirely clear. Research indicates possible influencing factors such as the intensification of anxiety symptoms, a tendency to worry, the presence of PTSD symptoms, and behavioral factors such as the consumption of psychoactive substances (caffeine, alcohol, nicotine), sleep deprivations and poor sleep hygiene. The study aimed to assess the prevalence of SP and determine the risk factors for the occurrence of SP in the population of Polish students. METHODS: The study used a battery online consisting of a set of questionnaires 1) a personal questionnaire, 2) the SP-EPQ, 3) the PCL -5, 4) the STAI-T, 5) the PSWQ. The questionnaire was sent via Facebook to 4500 randomly selected students from different universities in Poland. The questionnaire was completed by 2598 students. To unify the participant sample, people over 35 were excluded from the study (45 students). Ultimately, data from 2553 students were analyzed. RESULTS: A total of 33.14% of individuals experienced at least one episode of SP in their lives. The highest odds ratio for SP was associated with: the presence of three or more health problems (OR: 2.3; p = 0.002), the presence of any mental disorder (OR: 1.77; p = 0.002), including mood disorders (OR: 2.07; p = 0.002), suffering from at least one somatic disease (OR: 1.34; p = 0.002), a high level of anxiety as a constant personality trait (OR: 1.20; p = 0.035) and smoking (OR: 1.48; p = 0.0002), alcohol consumption (OR: 1.52; p < 0.0001), physical activity (OR: 1.31; p = 0.001). CONCLUSIONS: The results of our research indicate that a large proportion of students experienced isolated sleep paralysis. Mental and somatic health problems and lifestyle factors were found to predispose individuals to this disorder. Due to the numerous risk factors for SP, it is necessary to conduct additional research to confirm the impact of these factors and to investigate the mechanisms of their influence on SP.

Disorders of arousal and sleep-related hypermotor epilepsy - overview and challenges night is a battlefield of sleep and arousal promoting forces.

Arousability and reactivity to sensory stimuli are essential features of sleep, discriminating it from coma and keeping the sleeper in contact with the environment. Arousals and oscillations during sleep serve the reversibility of sleep and carry an alarm function awakening the sleeper in danger. In this review, we will explore mechanisms and circuits involved in arousal intrusions within the sleep texture, focusing on the significance of these phenomena in two sleep-related conditions: NREM sleep parasomnias and sleep-related hypermotor epilepsy. Knowledges and gaps in the field are discussed.

REM sleep behavior disorder as a complex condition with heterogeneous underlying disorders: clinical management and prognostic implications [Commentary].

PURPOSE: To review how REM sleep behavior disorder (RBD) is a complex condition with heterogeneous underlying disorders; and to review clinical management issues and prognostic implications. METHODS: PubMed literature search and contents from the first textbook of RBD (2018). RESULTS: RBD, with its core objective diagnostic feature of REM-without-atonia (RWA) documented by video-polysomnography, can emerge during the entire lifespan, and can initially present as an idiopathic (isolated) condition (iRBD), or can be associated with a broad spectrum of disorders including narcolepsy, alpha-synuclein neurodegenerative disorders (esp. Parkinson's disease [PD] and dementia with Lewy bodies [DLB]), paraneoplastic neurological syndromes and autoimmune disorders, CNS lesions (e.g., tumors, stroke), other neurological disorders, psychiatric disorders (PTSD, mood disorders), can be triggered by antidepressant/other medications, and can emerge acutely with drug withdrawal states, toxic-metabolic states, etc. Important clinical issues include the evolution of iRBD to PD/DLB in most middle-aged and older patients over a period of years to several decades, with compelling prognostic implications, along with the hope of enrolling these patients in future clinical trials to test promising disease-modifying therapies. Also, the strong link of RBD with narcolepsy needs further investigation. Parasomnia overlap disorder involves RBD and NREM parasomnias that can be idiopathic or linked with a broad range of clinical disorders. RBD usually responds to therapy consisting mainly of melatonin and/or clonazepam at bedtime. The complex associations of RBD with OSA are being increasingly investigated. RBD mimics with dream-enactment need to be recognized for diagnostic and management purposes, including severe OSA, NREM parasomnias, PLMD, nocturnal seizures, and other conditions. CONCLUSIONS: The clinical and research RBD fields span across the disciplines of neurology, pulmonary, psychiatry, psychology, and pediatric sleep medicine, along with physical medicine and rehabilitation medicine, other allied disciplines, and the basic and clinical neurosciences.

REM sleep, REM parasomnias, REM sleep behaviour disorder.

We review the literature on REM parasomnias, and their the underlying mechanisms. Several REM parasomnias are consistent with sleep dissociations, where certain elements of the REM sleep pattern emerge in an inadequate time (sleep paralysis, hypnagogic hallucinations and cataplexy) or are absent/partial in their normal REM sleep time (REM sleep without atonia, underlying REM sleep behavior disorder). The rest of REM parasomnias (sleep related painful erection, catathrenia) may have other still unclear mechanisms. REM parasomnias deserve attention, because in addition to disturbing sleep and causing injuries, they may shed light on REM sleep functions as well as the heterogeneous etiologies of parasomnias. One of them, REM sleep behavior disorder has special importance as a warning sign of evolving neurodegenerative conditions mainly synucleinopathies (some cases synucleinopathies themselves) and it is a model parasomnia revealing that parasomnias may have by autoimmune, iatrogenic and even psychosomatic etiologies.

"It Started After Trauma": The Effects of Traumatic Grief on Sleep Paralysis.

Adverse life events are associated with the often-terrifying REM sleep parasomnia of sleep paralysis (SP), but the impact of bereavement on SP has not been specifically examined. This exploratory, mixed-methods study (N = 168) includes qualitative data from 55 participants who described factors they believed led to their SP. Of these, almost half with a traumatic loss listed death-related precipitants. In unadjusted (bivariate) negative binomial regression models, traumatic death, time since death, religiosity, and age estimated increased SP frequency in the prior month, prior year, or both. In multivariable models, traumatic death, time since death, and age estimated increased frequency in the prior month, prior year, or both. Unexpectedly, in all models, as compared to death ≥9 years earlier, prior month SP was greater with death 1-6 years earlier, but not <1 year earlier. Discussion includes the possible role of social constraints in traumatic grief trajectories and care provider recommendations.

Prevalence and predictors of mood disturbances in idiopathic REM sleep behaviour disorder.

Depression and anxiety are commonly associated with synucleinopathies. Mood disturbances have also been reported in patients with idiopathic REM sleep behaviour disorder (iRBD) and are difficult to treat due to exacerbation of sleep symptoms with standard antidepressants. Despite this, detailed prevalence studies of mood symptomatology and contributors to mood disturbances in iRBD are limited. Mood, sleep, autonomic, cognitive and motor symptoms were assessed in 49 well-characterized patients with iRBD using a variety of clinical scales. Spearman correlations, factor analysis and multiple linear regression were used to uncover associations between mood and non-motor and motor symptoms. The prevalence of significant depression was 17.0% and that of anxiety was 14.6% in the iRBD cohort. Age and disease duration were not correlated with these affective symptoms in iRBD patients. We found depression was significantly predicted by the presence and severity of motor, sleep and cognitive symptoms. Anxiety was predicted by the severity of nocturnal and daytime sleep-related symptoms, cognitive symptoms and autonomic symptoms, with a differential effect depending on the questionnaire used. Depression and anxiety are common in iRBD patients and can be significantly explained by specific sets of non-motor and motor symptoms. These associations provide insight into the underlying pathophysiology and emphasize the importance of a holistic approach to mood disturbance in this population, which may circumvent the reliance on pharmacotherapy that can exacerbate dream enactment behaviour.

Exploding head syndrome, chronotype, parasomnias and mental health in young adults.

Although inadequate sleep among young people is well documented in the literature, anomalous sleep experiences, such as the parasomnia termed exploding head syndrome (EHS), have received little empirical attention. The current study examined the association of sleep quality, symptoms of psychological distress and other unusual sleep experiences with EHS in a sample of young adults (n = 135, age M = 21.77, SD = 2.08). We also aimed to account for the possible effect of participant chronotype on sleep experiences. The lifetime prevalence of EHS among participants was 20.0%. Three-quarters (75.6%) of participants reported poor quality sleep according to the Pittsburgh Sleep Quality Index (PSQI). Univariate analysis showed that participants with a lifetime prevalence of EHS experienced more symptoms of anxiety and poorer sleep quality; age, gender and symptoms of depression were not significantly related to EHS. Parasomnias (OR [95% CI] = 1.62 [1.02-2.57], p = .040) and action-related sleep disorders (OR [95% CI] = 1.87 [1.09-3.20], p = .023) were associated with lifetime experience of EHS in a logistic regression analysis. Chronotype did not significantly impact mood, sleep quality or presence of EHS. Results suggest that EHS is more common in young people than previously considered and ought to be examined in conjunction with the presence of other unusual sleep disorders. This study provides valuable insight into young peoples' sleep experiences and key factors associated with EHS.

Could sleep paralysis be pleasant?

Sleep paralysis is an inability to move at sleep onset or upon awakening. It is often a distressing experience that can be associated with significant clinical consequences. Few studies have focussed on pleasant sleep paralysis episodes. The present study aimed to determine the relative prevalence of pleasant episodes of sleep paralysis as well as variables that may make them more likely to occur. Participants (N = 172) with recurrent episodes of sleep paralysis completed a battery of questionnaires investigating sleep paralysis episodes, trauma symptoms, life satisfaction, and Big Five personality traits. Pleasant sleep paralysis was found to be a fairly common experience (i.e. 23%). Episodes were emotionally complex, with pleasant episodes often involving some admixture of fear. In terms of hallucinations, pleasant episodes were more likely to involve vestibular-motor sensations (i.e. illusory body movements) and some individuals reported an ability to induce these hallucinations. Contrary to expectation, neither lower trauma symptomatology nor higher levels of reported life satisfaction predicted pleasant sleep paralysis. However, the ability to lucid dream and higher levels of trait openness to new experiences appeared to make pleasant episodes more likely. Clinical implications are discussed.

Grumpy face during adult sleep: A clue to negative emotion during sleep?

Negative facial expressions and frowns have been studied (albeit more rarely than smiles) in fetus' and neonate' sleep, but they have not been investigated during adult sleep. Video polysomnography (including corrugator muscle electromyography and face-focussed video) was used to study negative facial expressions in sleeping adults, including healthy subjects and patients with/out parasomnia. Frowns were observed during sleep in 89/91 (97.8%) adults during normal (29 healthy subjects) and abnormal sleep (29 patients without parasomnia, 15 patients with disorders of arousal and 18 patients with rapid eye movement [REM] sleep behaviour disorder [RBD]). In healthy subjects, the following events occurred in decreasing frequency: isometric corrugator activations, brief frowns, and then prolonged frowns and raised eyebrows (both similarly rare). Frowns predominated in REM sleep, and had a lower frequency in non-REM sleep. In healthy subjects, frowns were elementary and not associated with other face movements to the point of composing negative expressions. In contrast, frowns were occasionally associated with overt negative facial expressions in REM sleep in patients with RBD and a young patient with night terrors. They included mostly painful expressions and rarely sadness and anger in connection with apparently negative behaviours (shouts, painful moaning, and speeches). Frowns persist during normal sleep (mostly in REM sleep) in adults, but overt negative facial expressions are restricted to patients with parasomnia. Whether elementary frowns translate a negative dream emotion should be determined, but overt negative facial expressions during RBD could be used as a direct access to dream emotions.

Exploding head syndrome (a.k.a. episodic cranial sensory shock) responds to single-pulse transcranial magnetic stimulation.

We present the case of a patient with a sleep disturbance attributed to the exploding head syndrome, recently redefined as episodic cranial sensory shock. The patient, who suffered with concomitant migraine, was treated for headache prevention with daily single-pulse transcranial magnetic stimulation (sTMS). Following treatment, he reported a significant reduction in the episodes of exploding head syndrome, albeit not of his migraine. Neurologists could consider sTMS in the management of patients troubled by episodic cranial sensory shock, as it is a safe and noninvasive treatment that might provide benefit for this benign but occasionally bothersome parasomnia.

In the twilight zone: An epidemiological study of sleep-related hallucinations.

BACKGROUND: Few studies have investigated hallucinations that occur at the onset/offset of sleep (called hypnagogic/hypnopompic hallucinations; HHHs), despite the fact that their prevalence in the general population is reported to be higher than the prevalence of daytime hallucinations. We utilized data from an epidemiological study to explore the prevalence of HHHs in various modalities. We also investigated phenomenological differences between sleep-related (HHHs) and daytime hallucinations in the auditory modality. We hypothesized that individuals with only HHHs would not differ from controls on a range of mental health and wellbeing measures, but that if they occur together with daytime hallucinations will pose a greater burden on the individual experiencing them. We also hypothesize that HHHs are qualitatively different (i.e. less severe) from daytime hallucinations. METHODS: This study utilized data from a cross-sectional epidemiological study on the prevalence of hallucinations in the Norwegian general population. The sample (n = 2533) was divided into a control group without hallucinations (n = 2303), a group only experiencing sleep-related hallucinations (n = 62), a group only experiencing daytime hallucinations (n = 57), and a group experiencing both sleep-related as well as daytime hallucinations (n = 111). Prevalence rates were calculated and groups were compared using analyses of variance and chi-square tests where applicable. RESULTS: The prevalence for HHHs in the auditory domain was found to be 6.8%, whereas 12.3% reported multimodal HHHs, and 32.2% indicated out-of-body experiences at the onset/offset of sleep. Group comparisons of hallucinations in the auditory modality showed that individuals that experienced only auditory HHHs scored significantly (p < 0.05) lower than those who also experienced daytime auditory hallucinations on a range of variables including mental health, anxiety, childhood happiness, and wellbeing. In addition, individuals with only auditory HHHs reported significantly (p < 0.05) less frequent hallucinations, less disturbing hallucinations, more neutral (in terms of content) hallucinations, hallucinations with less influence over their behavior, and less hallucination-related interference with social life compared to those individuals that experience daytime hallucinations. We also found that purely auditory HHHs had a significantly higher age of first onset of hallucinations than the purely daytime and the combined daytime and auditory HHHs groups (28.2 years>20.9 > 19.1). CONCLUSIONS: Sleep-related hallucinations are common experiences in the general population, with the auditory modality being the least common. They occur mostly in combination with daytime hallucinations. However, some individuals (2.4%) experience only (auditory) sleep-related hallucinations and this group can be seen as more closely related, on a range of health-related factors, to non-hallucinating individuals than individuals who experience daytime hallucinations. Finally, there is a clear need for more research in this field, and ideas for future studies are presented.