Exploding head syndrome is common in college students.

Exploding head syndrome is characterized by the perception of loud noises during sleep-wake or wake-sleep transitions. Although episodes by themselves are relatively harmless, it is a frightening phenomenon that may result in clinical consequences. At present there are little systematic data on exploding head syndrome, and prevalence rates are unknown. It has been hypothesized to be rare and to occur primarily in older (i.e. 50+ years) individuals, females, and those suffering from isolated sleep paralysis. In order to test these hypotheses, 211 undergraduate students were assessed for both exploding head syndrome and isolated sleep paralysis using semi-structured diagnostic interviews: 18.00% of the sample experienced lifetime exploding head syndrome, this reduced to 16.60% for recurrent cases. Though not more common in females, it was found in 36.89% of those diagnosed with isolated sleep paralysis. Exploding head syndrome episodes were accompanied by clinically significant levels of fear, and a minority (2.80%) experienced it to such a degree that it was associated with clinically significant distress and/or impairment. Contrary to some earlier theorizing, exploding head syndrome was found to be a relatively common experience in younger individuals. Given the potential clinical impacts, it is recommended that it be assessed more regularly in research and clinical settings.

Sleep Paralysis Among Egyptian College Students: Association With Anxiety Symptoms (PTSD, Trait Anxiety, Pathological Worry).

Among Egyptian college students in Cairo (n = 100), this study examined the relationship between sleep paralysis (SP) and anxiety symptoms, viz., posttraumatic stress disorder (PTSD), trait anxiety, and pathological worry. SP rates were high; 43% of participants reported at least one lifetime episode of SP, and 24% of those who reported at least one lifetime episode had experienced four or more episodes during the previous year. Fourteen percent of men had experienced SP as compared to 86% of women. As hypothesized, relative to non-SP experiencers, participants who had SP reported higher symptoms of PTSD, trait anxiety, and pathological worry. Also, as hypothesized, the experiencing of hypnogogic/hypnopompic hallucinations during SP, even after controlling for negative affect, was highly correlated with symptoms of PTSD and trait anxiety. The study also investigated possible mechanisms by examining the relationship of hallucinations to anxiety variables.

Recurrent Isolated Sleep Paralysis.

Recurrent isolated sleep paralysis has a 7.6% lifetime prevalence of at least one episode in the general population. Episodes resolve spontaneously and are benign. Sleep paralysis represents a dissociate state, with persistence of the rapid eye movement (REM)-sleep muscle atonia in the waking state. The intrusion of alpha electroencephalogram into REM sleep is followed by an arousal response and then by persistence of REM atonia into wakefulness. Predisposing factors include irregular sleep-wake schedules, sleep deprivation, and jetlag. No drug treatment is required. Patients should be informed about sleep hygiene. Cognitive behavioral therapy may be useful in cases accompanied by anxiety and frightening hallucinations.

Narcolepsy Severity Scale-2 and Idiopathic Hypersomnia Severity Scale to better quantify symptoms severity and consequences in Narcolepsy type 2.

STUDY OBJECTIVES: Narcolepsy type 2 (NT2) is an understudied central disorder of hypersomnolence sharing some similarities with narcolepsy type 1 and idiopathic hypersomnia (IH). We aimed: (1) to assess systematically the symptoms in patients with NT2, with self-reported questionnaires: Epworth Sleepiness Scale (ESS), Narcolepsy Severity Scale (NSS), IH Severity Scale (IHSS), and (2) to evaluate the responsiveness of these scales to treatment. METHODS: One hundred and nine patients with NT2 (31.4 ±â€…12.2 years old, 47 untreated) diagnosed according to ICSD-3 were selected in a Reference Center for Narcolepsy. They all completed the ESS, subgroups completed the modified NSS (NSS-2, without cataplexy items) (n = 95) and IHSS (n = 76). Some patients completed the scales twice (before/during treatment): 42 ESS, 26 NSS-2, and 30 IHSS. RESULTS: Based on NSS-2, all untreated patients had sleepiness, 58% disrupted nocturnal sleep, 40% hallucinations, and 28% sleep paralysis. On IHSS, 76% reported a prolonged nocturnal sleep, and 83% sleep inertia. In the independent sample, ESS and NSS-2 scores were lower in treated patients, with same trend for IHSS scores. After treatment, ESS, NSS-2, and IHSS total scores were lower, with a mean difference of 3.7 ±â€…4.1, 5.3 ±â€…6.7, and 4.1 ±â€…6.2, respectively. The minimum clinically important difference between untreated and treated patients were 2.1 for ESS, 3.3 for NSS-2, and 3.1 for IHSS. After treatment, 61.9% of patients decreased their ESS > 2 points, 61.5% their NSS-2 > 3 points, and 53.3% their IHSS > 3 points. CONCLUSIONS: NSS-2 and IHSS correctly quantified symptoms' severity and consequences in NT2, with good performances to objectify response to medications. These tools are useful for monitoring and optimizing NT2 management, and for use in clinical trials.

[Sleep paralysis during naptime as initial symptom of narcolepsy]. / Parálisis de sueño durante la siesta como síntoma inicial de narcolepsia.

INTRODUCTION: Narcolepsy is a disease of unknown etiology, with a very low prevalence (0.02-0.16% in adults, although it must be higher, given the underdiagnosis), characterized by the presence of excessive daytime sleepiness, hypnagogic and/or hypnopompic hallucinations, sleep paralysis and/or cataplexy (if present, we speak of type 1 narcolepsy and, if not, type 2 narcolepsy), whose average diagnostic delay is between 10 and 15 years. CASE REPORT: A 16-year-old male who consulted after visiting different specialists for presenting sleep paralysis during naps, which cause him fear and occasional objects falling from his hands (diagnosed as possible myoclonus). In the anamnesis we were surprised by the presence of sleep paralysis immediately after the start of the naps and, in the directed anamnesis, these sudden movements caused by emotions were compatible with cataplexies, so we performed a nocturnal polysomnographic study and a multiple sleep latency test. With evolution came hypnopompic hallucinations and fragmented nocturnal sleep, as well as occasional daytime sleepiness (thus completing the typical symptomatic tetrad of type 1 narcolepsy with cataplexy). CONCLUSION: Knowledge of this disease is important, considering it as a differential diagnosis in patients with episodes of intractable sleepiness, send these patients to expert doctors in sleep disorders and doing a good anamnesis, performing the necessary complementary tests for the diagnosis of this underdiagnosed disease for its correct management, which is decisive for improving the quality of life of these patients.

TITLE: Parálisis de sueño durante la siesta como síntoma inicial de narcolepsia.Introducción. La narcolepsia es una enfermedad de etiología desconocida, de prevalencia muy baja (el 0,02-0,16% en adultos, aunque debe ser mayor, dado el infradiagnóstico), caracterizada por la presencia de somnolencia diurna excesiva, alucinaciones hipnagógicas y/o hipnopómpicas, parálisis de sueño y/o cataplejía (si está presente, se habla de narcolepsia de tipo 1 y, si no, de narcolepsia de tipo 2), cuya media de retraso diagnóstico se sitúa entre los 10 y los 15 años. Caso clínico. Varón de 16 años que consulta tras visitar a distintos especialistas por presentar parálisis de sueño durante las siestas, que le producen miedo y ocasional caída de objetos de las manos (diagnosticadas como posibles mioclonías). En la anamnesis nos sorprendió la presencia de parálisis de sueño inmediatamente tras el inicio de las siestas y, en la anamnesis dirigida, esos movimientos bruscos provocados por emociones eran compatibles con cataplejías, por lo que realizamos un estudio polisomnográfico nocturno y un test de latencias múltiples del sueño. Con la evolución aparecieron alucinaciones hipnopómpicas y sueño fragmentado nocturno, así como ocasional somnolencia diurna (se completó así la tétrada sintomatológica típica de la narcolepsia con cataplejía de tipo 1). Conclusión. Es importante el conocimiento de esta enfermedad, plantearla como diagnóstico diferencial en pacientes con episodios de somnolencia incoercible, realizar la derivación a consultas especializadas en trastornos de sueño y una buena anamnesis dirigida, e indicar las pruebas complementarias necesarias para el diagnóstico de esta enfermedad infradiagnosticada para su correcto manejo, tan determinante para la mejora de la calidad de vida de estos pacientes.

Nightmare Disorder and Isolated Sleep Paralysis.

Nightmare disorder and recurrent isolated sleep paralysis are rapid eye movement (REM) parasomnias that cause significant distress to those who suffer from them. Nightmare disorder can cause insomnia due to fear of falling asleep through dread of nightmare occurrence. Hyperarousal and impaired fear extinction are involved in nightmare generation, as well as brain areas involved in emotion regulation. Nightmare disorder is particularly frequent in psychiatric disorders and posttraumatic stress disorder. Nonmedication treatment, in particular imagery rehearsal therapy, is especially effective. Isolated sleep paralysis is experienced at least once by up to 40% of the general population, whereas recurrence is less frequent. Isolated sleep paralysis can be accompanied by very intense and vivid hallucinations. Sleep paralysis represents a dissociated state, with persistence of REM atonia into wakefulness. Variations in circadian rhythm genes might be involved in their pathogenesis. Predisposing factors include sleep deprivation, irregular sleep-wake schedules, and jetlag. The most effective therapy consists of avoiding those factors.

Isolated sleep paralysis and fearful isolated sleep paralysis in outpatients with panic attacks.

Isolated sleep paralysis (ISP) has received scant attention in clinical populations, and there has been little empirical consideration of the role of fear in ISP episodes. To facilitate research and clinical work in this area, the authors developed a reliable semistructured interview (the Fearful Isolated Sleep Paralysis Interview) to assess ISP and their proposed fearful ISP (FISP) episode criteria in 133 patients presenting for panic disorder treatment. Of these, 29.3% met lifetime ISP episode criteria, 20.3% met the authors' lifetime FISP episode criteria, and 12.8% met their recurrent FISP criteria. Both ISP and FISP were associated with minority status and comorbidity. However, only FISP was significantly associated with posttraumatic stress disorder, body mass, anxiety sensitivity, and mood and anxiety disorder symptomatology.

RECURRENT SLEEP PARALYSIS - FEAR OF SLEEPING.

OBJECTIVE: To report a case of recurrent isolated sleep paralysis (RISP), a benign parasomnia with worrisome and frightening sleep paralysis episodes. CASE: description: We describe a case of RISP in a sixteen-year-old girl who seeks medical attention for anxiety symptoms. The sleep paralysis and associated auditory and tactile hallucinations began three years before with worsening in the last year, causing fear of sleeping. The episodes were intensely frightening causing negative impact in patient's sleep, school performance and social function. Medical conditions were excluded, and she started treatment with a selective serotonin reuptake inhibitor with complete resolution of symptoms. COMMENTS: Sleep complaints are often devalued. Therefore, clinicians should actively ask their patients about their sleep during health assessment.

Anxiety and sleep problems: emerging concepts and theoretical treatment implications.

The high prevalence and comorbidity of anxiety and sleep problems, especially insomnia, suggest an important underlying relationship between these disorders. In this article, we highlight two theoretical models explaining this co-occurrence, provide a brief update on the association between anxiety-insomnia and anxiety-cataplexy in general, and review more specifically sleep problems in generalized anxiety, post-traumatic stress disorder, and panic disorder. We also explore sleep paralysis as an anxiety-sleep event. Our goal with this examination of selective anxiety-sleep problems is to provide clues about diagnostic and treatment approaches and frame strategies for future research.

Focal epileptic seizures mimicking sleep paralysis.

Sleep paralysis (SP) is a common parasomnia. The diagnostic criteria for SP, as reported in the International Classification of Sleep Disorders, are essentially clinical, as electroencephalography (EEG)-polysomnography (PSG) is not mandatory. We describe a subject whose sleep-related events fulfilled the diagnostic criteria for SP, even though her visual hallucinations were elementary, repetitive and stereotyped, thus differing from those usually reported by patients with SP. Video/EEG-PSG documented the focal epileptic nature of the SP-like episodes.

Sleep paralysis in adolescents: the 'a dead body climbed on top of me' phenomenon in Mexico.

AIMS: The aim of the present study was to evaluate the prevalence and characteristics of sleep paralysis in adolescents using a folk expression. METHODS: Three hundred and twenty-two adolescents (mean age, 15.9 +/- 0.88 years; 66.8% female) from three high schools in Mexico City completed both a self-reported questionnaire, including a colloquial definition of sleep paralysis and the Epworth Sleepiness Scale. RESULTS: A high proportion of the adolescents (92.5%) had heard about the 'a dead body climbed on top of me' expression and 27.6% of them had experienced the phenomenon. Sleep paralysis was present in 25.5% while the prevalence rate for hypnagogic/hypnopompic hallucinations was 22%; 61% had experienced >or=2 episodes in their lifetime. The mean age of onset was 12.5 +/- 3 years. Sleepiness scores for the subjects who had experienced at least one event were not significantly different from subjects who had not experienced any. In 72% of cases, the episodes were composed of both sleep paralysis and hallucinations while 20.2% consisted of only sleep paralysis and 7.8% of only hallucinations. The number and characteristics of events were not significantly different between adolescents with only one episode and those with two or more episodes. CONCLUSIONS: The characteristics of the 'a dead body climbed on top of me' phenomenon suggest that is identical to sleep paralysis and a frequent experience among Mexican adolescents. During adolescence, sleep paralysis seems to be a recurrent phenomenon frequently accompanied by hallucinatory experiences.

Narcolepsy and psychotic states--a case report.

Narcolepsy is characterized by symptoms that include excessive sleepiness during the daytime, cataplexy, hypnagogic hallucinations and sleep paralysis. We present a single unusual case report of a patient who was admitted to a psychiatric facility. A 20-year-old single woman was hospitalized in a general hospital due to involuntary movements in her limbs. Following complaints of continual daily sleepiness and instances of a loss of muscle tone she was referred for sleep assessment. The patient was diagnosed with narcolepsy and cataplexy. Later, due to auditory hallucinations she was referred to a psychiatric hospital. Her reality judgement was poor, with partial insight regarding her illness. The patient was treated with methylphenidate 20 mg/day and antipsychotic medication; risperidone of up to 4 mg/day, and paroxetine 20 mg/day to prevent cataplexy. Following further exacerbation, pharmacotherapy was changed to risperidone 6 mg/day and modafinil 200 mg/day. This treatment led to a significant improvement in her condition. The report presented here suggests that combined treatment with a psycho-stimulant drug, an SSRI in combination with antipsychotic treatment, may be indicated in narcolepsy with cataplexy and vivid psychotic production. Multidisciplinary cooperation of neurologists and psychiatrists enabled this therapy to be administered for the patient's benefit.

Sleep paralysis and trauma, psychiatric symptoms and disorders in an adult African American population attending primary medical care.

The occurrence of sleep paralysis (SP) absent narcolepsy appears to not be uncommon in African Americans and probably other non-European groups. Prior research has linked SP to trauma and psychiatric disorders and suggested a specific relationship to panic disorder in African Americans. The objective of our study was to evaluate relationships of SP with trauma, concurrent psychiatric symptoms and lifetime psychiatric diagnoses in an adult African American population recruited from primary care. Cross sectional study with surveys and diagnostic interviews; Patients attending primary care clinics filled out a survey that determined the 6 month prevalence and associated features of SP, a panic disorder screen, the self-rated Hamilton Depression Scale, and an inventory of trauma exposure. A subset of trauma-exposed participants (N = 142) received comprehensive diagnostic interviews that incorporated the Structured Clinical Interview for DSM-IV and the Clinician Assessed PTSD Scale. Four hundred and forty-one adults participated (mean age-40.0 SD = 13.3, 68% female, 95% African American). Fourteen percent endorsed recent SP. In approximately 1/3 of those with SP, episodes also featured panic symptoms. SP was strongly associated with trauma history, and concurrent anxiety and mood symptoms. SP was not associated with specific psychiatric disorders other than lifetime (but not current) alcohol or substance use disorders. Our findings suggest that SP is not uncommon in adult African Americans and is associated with trauma and concurrent distress but not with a specific psychiatric diagnosis.

Prevalence and correlates of sleep paralysis in adults reporting childhood sexual abuse.

Sleep paralysis (SP) occurs when rapid eye movement (REM) activity and concomitant paralysis of the skeletal muscles persist as an individual awakens and becomes conscious of his/her surroundings. SP is often accompanied by frightening hallucinations that some researchers suggest may be confounded with memories of childhood sexual abuse (CSA; [McNally, R. J., & Clancy, S. A. (2005). Sleep paralysis in adults reporting repressed, recovered, or continuous memories of childhood sexual abuse. Journal of Anxiety Disorders, 19, 595-602]). The purpose of this study was to evaluate relationships between CSA and SP. Based on self-report, participants (n=263) were categorized into three CSA groups: confirmed, unconfirmed, or no history of CSA. Relative to participants reporting no CSA history, those reporting CSA reported more frequent and more distressing episodes of SP. Post hoc analyses revealed that participants with clinically significant post-traumatic symptoms (irrespective of CSA history) also reported more frequent and more distressing episodes of SP. Significant correlations were found among SP indices and measures of post-traumatic symptoms, depression, dissociation, and absorption. Implications and future research directions are discussed.

A systematic review of variables associated with sleep paralysis.

Sleep paralysis is a relatively common but under-researched phenomenon. While the causes are unknown, a number of studies have investigated potential risk factors. In this article, we conducted a systematic review on the available literature regarding variables associated with both the frequency and intensity of sleep paralysis episodes. A total of 42 studies met the inclusion criteria. For each study, sample size, study site, sex and age of participants, sleep paralysis measure, and results of analyses looking at the relationship(s) between sleep paralysis and associated variable(s) were extracted. A large number of variables were associated with sleep paralysis and a number of themes emerged. These were: substance use, stress and trauma, genetic influences, physical illness, personality, intelligence, anomalous beliefs, sleep problems and disorders (both in terms of subjective sleep quality and objective sleep disruption), symptoms of psychiatric illness in non-clinical samples (particularly anxiety symptoms), and psychiatric disorders. Sleep paralysis appears to be particularly prevalent in post-traumatic stress disorder, and to a less degree, panic disorder. Limitations of the current literature, directions for future research, and implications for clinical practice are discussed.

The inappropriate occurrence of rapid eye movement sleep in narcolepsy is not due to a defect in homeostatic regulation of rapid eye movement sleep.

Narcolepsy type 1 is a disabling disorder with four primary symptoms: excessive-daytime-sleepiness, cataplexy, hypnagogic hallucinations, and sleep paralysis. The later three symptoms together with a short rapid eye movement (REM) sleep latency have suggested impairment in REM sleep homeostatic regulation with an enhanced propensity for (i.e. tendency to enter) REM sleep. To test this hypothesis, we challenged REM sleep homeostatic regulation in a recognized model of narcolepsy, the orexin knock-out (Orex-KO) mice and their wild-type (WT) littermates. We first performed 48 hr of REM sleep deprivation using the classic small-platforms-over-water method. We found that narcoleptic mice are similarly REM sleep deprived to WT mice. Although they had shorter sleep latency, Orex-KO mice recovered similarly to WT during the following 10 hr of recovery. Interestingly, Orex-KO mice also had cataplexy episodes immediately after REM sleep deprivation, anticipating REM sleep rebound, at a time of day when cataplexy does not occur in baseline condition. We then evaluated REM sleep propensity using our new automated method of deprivation that performs a specific and efficient REM sleep deprivation. We showed that REM sleep propensity is similar during light phase in Orex-KO and WT mice. However, during the dark phase, REM sleep propensity was not suppressed in Orex-KO mice when hypocretin/orexin neuropeptides are normally released. Altogether our data suggest that in addition to the well-known wake-promoting role of hypocretin/orexin, these neuropeptides would also suppress REM sleep. Therefore, hypocretin/orexin deficiency would facilitate the occurrence of REM sleep at any time of day in an opportunistic manner as seen in human narcolepsy.

CSF hypocretin-1 levels and clinical profiles in narcolepsy and idiopathic CNS hypersomnia in Norway.

OBJECTIVE: To evaluate the relationship between CSF hypocretin-1 levels and clinical profiles in narcolepsy and CNS hypersomnia in Norwegian patients. METHOD: CSF hypocretin-1 was measured by a sensitive radioimmunoassay in 47 patients with narcolepsy with cataplexy, 7 with narcolepsy without cataplexy, 10 with idiopathic CNS hypersomnia, and a control group. RESULTS: Low hypocretin-1 values were found in 72% of the HLA DQB1*0602 positive patients with narcolepsy and cataplexy. Patients with low CSF hypocretin-1 levels reported more extensive muscular involvement during cataplectic attacks than patients with normal levels. Hypnagogic hallucinations and sleep paralysis occurred more frequently in patients with cataplexy than in the other patient groups, but with no correlation to hypocretin-1 levels. CONCLUSION: About three quarters of the HLA DQB1*0602 positive patients with narcolepsy and cataplexy had low CSF hypocretin-1 values, and appear to form a distinct clinical entity. Narcolepsy without cataplexy could not be distinguished from idiopathic CNS hypersomnia by clinical symptoms or biochemical findings.

Paranoid delusions and threatening hallucinations: a prospective study of sleep paralysis experiences.

Previously we reported a three-factor structure for hallucinations accompanying sleep paralysis (SP). These earlier analyses were, however, based on retrospective accounts. In a prospective study, 383 individuals reported individual episodes online providing further evidence for the three-factor structure as well as clearer conceptually meaningful relations among factors than retrospective studies. In addition, reports of individual episodes permitted a more fine-grained analysis of the internal structure of factors to assess predictions based on the hypothesis that a sensed or felt presence (FP) is a core experience affecting other SP hallucinations. Results were generally consistent with this hypothesis. In particular, associations among, and temporal stability of, sensory hallucinations were largely explained by their common association with FP. The findings are consistent with REM initiation of a threat activated vigilance system with pervasive effects on the SP experience and suggest a potential model for the thematic organization of nightmares and dreams more generally.

Felt presence: paranoid delusion or hallucinatory social imagery?

Cheyne and Girard characterize felt presence (FP) during sleep paralysis attacks as a pre-hallucinatory expression of a threat-activated vigilance system. While their results may be consistent with this interpretation, they are nonetheless correlational and do not address a parsimonious alternative explanation. This alternative stipulates that FP is a purely spatial, hallucinatory form of a common cognitive phenomenon-social imagery-that is often, but not necessarily, linked with threat and fear and that may induce distress among susceptible individuals. The occurrence of both fearful and non-fearful FPs in a multiplicity of situations other than sleep paralysis attacks supports the notion that FPs are hallucinatory variants of social imagery and that they are not necessarily bound to threat-activated vigilance. Evidence linking FPs with anxiety disorders supports the notion that the distress they evoke may be mediated by a more general affective distress personality factor. To illustrate the predominantly spatial character of FP hallucinations, similarities between FP and phantom limbs are summarized and the possibility that these two phenomena are parallel expressions (self- vs. other-presence) of a mirror neuron system is considered.