Hallucination-like experiences HLEs are typically defined as sensory perceptions in the absence of external stimuli. Multidimensional tools, able to assess different facets of HLEs, are helpful for a better characterization of hallucination proneness and to investigate the cross-national variation in the frequencies of HLEs. A total of respondents from 10 countries were enrolled. Confirmatory factor analysis was used to test its measurement invariance. The best fit was a 4-factor model, which proved invariant by country and clinical status, indicating cross-national stability of the hallucination-proneness construct. Among the different components of hallucination-proneness, auditory-visual HLEs had the strongest association with the positive dimension of the CAPE, compared with the depression and negative dimensions.
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Hallucination-like experiences HLEs are typically defined as sensory perceptions in the absence of external stimuli. Multidimensional tools, able to assess different facets of HLEs, are helpful for a better characterization of hallucination proneness and to investigate the cross-national variation in the frequencies of HLEs. A total of respondents from 10 countries were enrolled. Confirmatory factor analysis was used to test its measurement invariance.
The best fit was a 4-factor model, which proved invariant by country and clinical status, indicating cross-national stability of the hallucination-proneness construct.
Among the different components of hallucination-proneness, auditory-visual HLEs had the strongest association with the positive dimension of the CAPE, compared with the depression and negative dimensions. Small effect size differences by country were found in the scores of the 4 LSHS-E factors even after taking into account the role of socio-demographic and clinical variables. Hallucinations and related phenomena involve sensorial experiences in the absence of stimuli that are accessible to others.
HLEs are frequently associated with delusional beliefs of a kind often observed in psychotic disorders, which are hence defined as psychotic-like experiences PLEs. In a review on the topic, Johns et al 2 showed that auditory-verbal HLEs share several similarities with auditory-verbal hallucinations, but also reported that there are qualitative differences along the continuum, particularly regarding the role of risk factors in determining the transition from non-clinical to clinical status.
The investigation of HLEs is important in order to explore how perceptual anomalies become more pathological aberrations before there is a psychotic change in the way in which the sensory world is perceived and understood by a subject. However, depending on the response format used and the number of items included in the scale, different factorial structures were found. These structures included 2-factor, 10 , 15 3-factor, 6 , 17—19 4-factor, 9 , 13 , 20—22 and 5-factor 16 models.
Furthermore, despite the globalization of research on the factor structure of the LSHS-Extended LSHS-E , no study to date has explored the measurement invariance of this tool across countries and clinical status. The establishment of measurement invariance is a prerequisite to compare groups, since it provides evidence on whether respondents representing different clinical or socio-cultural backgrounds are interpreting a given measure in a conceptually similar manner.
There is evidence that the proportion of people with HLEs varies across countries and this may be a reflection of differing socio-cultural backgrounds and different distribution of psychotic disorders across countries.
Wide variance was found across countries, from rates as low as 0. In the WHO-WMHS, lifetime prevalence rates and estimates were based on age- and gender-weighted data and were detailed for both visual 3. A higher prevalence of HLEs was found to be associated with being younger 16—19 years 28 being female and unmarried vs being married, in the WHS , 25 unemployed 27 and having less education. Past research into the cross-national proportion of people with hallucinations and HLEs in the general population has been limited by the use of single-item indicators, as in the WHO-WMHS, which makes it difficult to assess the reliability of the reported experience.
Moreover, studies collapsed the data on auditory and visual HLEs into a single item, as in the WHS, 25 and overlooked other sensorial modalities, or used a broader construct of hallucination-proneness.
Multidimensional tools can be evaluated for their reliability and convergent, divergent and predictive validity, and for measurement invariance in particular, a prerequisite for comparing means across groups. The study protocol conforms to the guidelines of the Declaration of Helsinki and its revisions. Informed consent was obtained online from all participants in accordance with the requirements of the local ethics committee.
However, India was excluded from analysis because not enough data was collected. Data was stored in an anonymous manner. The study was carried out between winter and summer The study had a cross-sectional design and was carried out online through the Webropol Survey platform. Participants were invited through advertisements in social media Facebook, Institutional webs, etc. Participation was voluntary and no fee or other compensation was provided.
Participants were required to exclude any experiences where they might have been under the effect of drugs or alcohol. Inclusion criteria were: aged 18 years and older. Self-report data on sex, age, education, civil status, occupational status, family income, and past diagnosis of a mental or neurological disorder was used to define the socio-demographic and clinical characteristics of the sample.
Variables were dichotomized to examine the associations between socio-demographic factors and indicators of HLEs. The item LSHS-E taps into multiple sensory modalities including auditory, visual, olfactory and tactile, as well as hypnagogic and hypnopompic hallucinations and sensed presence ie, the experience of feeling the presence of someone close who has died. Standard translation and back-translation procedures were followed in the adaptation of the questionnaires to languages for which a validated version was unavailable ie, Brazilian, Chilean, Greek, Polish, Portuguese,.
For each factor, the scores were calculated by adding the responses to their respective items and dividing the sum by the number of items included in the factor, so as to preserve the 0 to 4 rating.
Higher scores 3 or 4 indicated a greater likelihood of experiencing the phenomena summarized in the factor. Standard translation and back-translation procedures were followed for languages for which a validated version was unavailable Polish. Additional analyses were carried out with dedicated packages running in R. Measurement invariance was calculated according to Byrne and van de Vijver 37 by using the R-package semTools. Regularization is a statistical procedure that restricts the links between variables to their unique variance, ie, after controlling for the effects of all the other variables, thus avoiding the estimation of spurious links.
These analyses were done with the bootnet package for R. For each variable, we assessed its relationship with the construct measured by the LSHS-E dimensions by taking into account all other variable as covariates.
The following variables were entered into these analyses: sex, age, education, civil status, employment, family income, and diagnosis, as previously defined.
Sensitivity analysis was conducted to explore any potential effects of caffeine, tobacco, marihuana, and alcohol on the HLEs. Spearman correlation was performed to analyze the associations between substance use and the 4 LSHS-E factors. A total of participants from 10 countries were involved in the study. About two-thirds of the sample were women table 1. Overall, 86 participants 1. The items are ranked according to the frequency of positive endorsement. Subsequently, 2 sets of measurement invariance CFA were applied: one to assess measurement invariance across countries; and the other to verify whether the best model was invariant between people who reported a diagnosis of mental disorder and those who did not.
In people who did not report a diagnosis, all CFA models were identified and all models reached the threshold for a good fit, except on the chi-square test, as is often the case with large samples. The models with the best fit were the 5-factor and the 4-factor models. However, the 5-factor model had a factor with just 2 items.
Thus, the 4 factors model was judged to be the most parsimonious model with the best fit and was consequently selected for interpretation and invariance testing. Table 2 summarizes the results of the measurement invariance CFA across countries.
The best model was implemented in all countries with large enough samples for model convergence excluding Argentina and the United Kingdom. A good model-fit was found in all country-samples table 2.
Measurement invariance was conducted across the 5 countries with enough data for this analysis ie, Belgium, Chile, Germany, Greece, and Spain. Fit was good in all countries and across all levels of the measurement invariance test. There was some degradation of the fit from configural to scalar invariance, with the delta-CFI but not the delta-RMSEA above the conventional threshold for invariance acceptability.
Results indicated an optimal fit in both samples. Measurement invariance was deemed acceptable at all levels of comparison. Network graph of the links among the 3 dimensions of the CAPE and the 4 factors of the LSHS-E in putatively healthy people on the left and in people who reported a diagnosis of a mental disorder on the right.
Thickness of the lines is proportional to the estimated correlation coefficients, which are superimposed on the lines. After taking into account all other variables, in the whole sample women scored higher than men, particularly on the intrusive thoughts and multisensory HLEs dimensions of LSHS-E. The effect size of this difference was modest. Being married, having a university degree or higher education, and being employed were related to lower scores on the LSHS-E dimensions.
The effect sizes of these associations were small. People who reported a diagnosis of a mental disorder scored higher on the LSHS-E dimensions, both overall and on each factor. After taking into account all other variables, age, and family income were not related to the LSHS-E dimensions see supplementary table S4 for the details.
Taking into account the socio-demographic and clinical variables, scores on the LSHS-E dimensions differed by sample at country level, both overall and on each single dimension. The effect sizes of these differences were small table 3 and supplementary table S5. People who declared a past neurological disorder were excluded. For some variables, information was occasionally missing. Participants from Belgium and Poland, and Brazil in some aspects sometime, tended to score higher than participants from other countries, while participants from Argentina and Portugal tended to score lower than participants from other countries.
Data are marginal means as estimated on the basis of the multivariate analyses of covariance MANCOVA taking into account the role of socio-demographic and clinical variables. Overall, Marihuana and tobacco were positively related to the LSHS-E dimensions except to vivid daydreams for tobacco.
Caffeine was negatively related to all dimensions except to multisensory HLEs and alcohol was only related to Auditory-visual HLEs supplementary table S5. Taking into account substance use, and socio-demographic and clinical variables, the differences on the 4 LSHS-E dimensions by country did not change significantly supplementary table S6.
This study provides evidence for the use of the LSHS-E as a tool to measure hallucination-proneness in epidemiological studies. The most important contribution of this study is the demonstration that the best model as retrieved by CFA was reproducible across countries and measurement invariance of the model could be demonstrated in 5 countries that had enough data for the algorithm to converge.
This finding confirmed that the multidimensional articulation of hallucination proneness can be reproduced across countries with different languages and cultures. Other studies have confirmed the multidimensionality of this scale in various versions.
This study replicated the 4-factor structure of the LSHS-E as reported by previous studies, 13 , 20 , 21 providing some consistency for 4-factors of the propensity to experience HLEs in the general population. As expected, the 4 factors identified were more closely related to the CAPE positive dimension than to the negative and depressive dimensions.
People who reported having received a diagnosis of a mental disorder were more likely to admit HLEs than healthy people and scored higher on the 4 LSHS-E dimensions even when socio-demographic variables were taken into account.
Conversely, people with a high educational level, those who declared themselves married and those who reported having a job scored lower than their counterparts on the 4 LSHS-E dimensions.
This is in line with past studies that also showed that young age, being unemployed and being unmarried was associated with the reporting of HLEs. Other explanations that have been put forward are that the impact of age might be due to a physiological, neurodevelopmental stage favoring the expression of psychosis proneness 45 and that hallucinations might be less prevalent in highly-educated populations because of their strong association with social adversity that is less prevalent in groups with higher-socioeconomic status.
Women scored higher than men with modest effect sizes on the intrusive thoughts and multisensory HLEs dimensions. Previous studies reported a greater occurrence of HLEs in women across countries with different cultural belonging. One possibility is the greater propensity of women to disclose symptoms of distress, 50 with HLEs being related to distress in both clinical and nonclinical samples.
Although repeated measurement designs are necessary to establish temporal associations, we can speculate that the presence of intrusive thoughts may be a crucial factor in generating hallucinations in people with psychosis. Another possibility could be that intrusive thoughts and HLEs might represent a variation of the same phenomenon, which is described in different ways by different people. Raballo 51 has argued that the HLEs are phenomena arising from the general transformation of the thought stream.
Humpston, 56 further, argued that auditory-verbal HLEs are the results of a thought process, and suggested that the intensity of thinking and related distress might cause an alienation from unwanted thoughts that then turn into auditory-verbal HLEs.
Revision of the factor structure of the Launay-Slade Hallucination Scale (LSHS-R)
In this study, we asked people from two samples a clinical one, consisting of patients with schizophrenia, and a non-clinical one, including university students to complete the Revised Hallucination Scale RHS as a self-questionnaire. When the participants responded positively to an item, they were encouraged to provide further detailed descriptions i. We found that the kinds of descriptions provided by the two groups were very different. We suggest that it is not advisable to explore the presence of hallucinations in non-clinical samples using research protocols based exclusively on yes-or-no answers to questionnaires like the RHS.
Quality of hallucinatory experiences: differences between a clinical and a non-clinical sample