RESUMO
Background: The incubus phenomenon is a paroxysmal sleep-related disorder characterized by the visuotactile sensation of a person or entity exerting pressure on one's thorax during episodes of sleep paralysis and (apparent) wakefulness. This terrifying phenomenon is relatively unknown even though a previous meta-analysis indicated a lifetime prevalence of 0.11 for individuals in the general population and of 0.41 for selected at-risk groups, including people diagnosed with schizophrenia and students. Since the studies reviewed did not always make a strict distinction between the incubus phenomenon and isolated sleep paralysis, we carried out a cross-sectional study in a contemporary patient and student sample to attain current, more detailed data on the incubus phenomenon. Materials and methods: In a cross-sectional design, we used the Waterloo Unusual Sleep Experience Questionnaire (WUSEQ) to screen patients with severe psychiatric disorders and university undergraduates to establish and compare prevalence rates, frequencies of occurrence, and risk factors for the incubus phenomenon. Results: Having interviewed 749 people, comprising 606 students and 143 patients with a schizophrenia spectrum or related disorder who had been acutely admitted to a secluded nursing ward, we computed a reported lifetime prevalence of 0.12 and 0.09, respectively, which rates were not statistically different. In both groups, the phenomenon was more common in people with a non-Western European background. Risk factors noted for the students were the use of psychotropic medication and the lifetime presence of an anxiety disorder, eating disorder, or sleeping disorder. We found no associations with age or gender in either group. Conclusion: The 0.09 and 0.12 lifetime prevalence rates we recorded for the incubus phenomenon in students and psychiatric inpatients is substantially lower than the 0.41 found in an earlier meta-analysis. We tentatively attribute this difference to an overgeneralization in previous studies but also discuss alternative explanations. The elevated prevalence among non-Western European participants may well be due to the fact that the topic continues to be part of the cultural and religious heritage of many non-Western countries.
RESUMO
BACKGROUND: The incubus phenomenon is a paroxysmal sleep-related disorder characterized by compound hallucinations experienced during brief phases of (apparent) wakefulness. The condition has an almost stereotypical presentation, characterized by a hallucinated being that exerts pressure on the thorax, meanwhile carrying out aggressive and/or sexual acts. It tends to be accompanied by sleep paralysis, anxiety, vegetative symptoms, and feelings of suffocation. Its prevalence rate is unknown since, in prior analyses, cases of recurrent isolated sleep paralysis with/without an incubus phenomenon have been pooled together. This is unfortunate, since the incubus phenomenon has a much greater clinical relevance than isolated sleep paralysis. METHODS: PubMed, Embase, and PsycINFO were searched for prevalence studies of the incubus phenomenon, and a meta-analysis was performed. RESULTS: Of the 1,437 unique records, 13 met the inclusion criteria, reporting on 14 (k) independent prevalence estimates (total N = 6,079). The pooled lifetime prevalence rate of the incubus phenomenon was 0.19 [95% confidence interval (CI) = 0.14-0.25, k = 14, N = 6,079] with heterogeneous estimates over different samples. In selected samples (e.g., patients with a psychiatric disorder, refugees, and students), prevalence rates were nearly four times higher (0.41, 95% CI = 0.25-0.56, k = 4, n = 1,275) than in the random samples (0.11, 95% CI = 0.08-0.14, k = 10, n = 4,804). This difference was significant (P < 0.001). CONCLUSION: This review and meta-analysis yielded a lifetime prevalence of the incubus phenomenon in the general population of 0.11 and, in selected samples, of 0.41. This is slightly higher than the prevalence rates in previous analyses that included cases of recurrent isolated sleep paralysis without an incubus phenomenon. Based on the condition's robust clinical presentation and the relatively high prevalence rates, we advocate inclusion of the incubus phenomenon as a diagnostic category in major classifications such as the International Classification of Diseases and Related Health Problems and the Diagnostic and Statistical Manual of Mental Disorders. Recommendations are also made for clinical practice and future research.
RESUMO
Thrombocytopenia is common in trauma and critically ill patients and is associated with a poor outcomes. The objective of this retrospective study was to investigate the course of thrombocyte concentration changes in burn patients, the influences of various factors on this course, and a possible predictive value of thrombocyte counts on outcome in 244 patients admitted to our burn centre. Their thrombocyte counts were obtained until 50 days after burn. Data on patient demographics, total percentage burned surface area (%TBSA), sepsis and mortality were collected. Multilevel multivariable analysis was performed to investigate the influence of the variables on the platelet course. Cox regression analysis was performed to analyse the predictive value of the variables for mortality. A distinct pattern of thrombocyte counts was observed, with a nadir at day 3 followed by a peak at day 15 and a temporary thrombocytosis. %TBSA and age (p<0.05) influence this course. The mean thrombocyte course of septic and non-surviving patients depicts a significant lower nadir. Furthermore, higher age, %TBSA and low thrombocyte counts at the peak are predictive for 50 day mortality (p<0.05). Platelets follow a distinct course after burn, influenced by %TBSA and age. These factors and a low thrombocyte peak count predict mortality.
