Latent structure of psychotic experiences in the general population

Ahmed AO, Buckley PF, Mabe PA. Latent structure of psychotic experiences in the general population. Objective: There have been increasing pressures to adopt or incorporate dimensional representations in various sections of DSM‐5 including the psychotic disorders section. Thus far, findings offered as evidence of a continuous distribution of psychosis are limited given their exclusive focus on the manifest rather than latent structure of psychotic experiences. The current study sought to determine whether or not psychotic experiences possess a taxonic or dimensional latent structure. Method: We investigated the latent structure of psychotic experiences in the Collaborative Psychiatric Epidemiological Surveys (CPES) and the National Comorbidity Survey (NCS). We analyzed responses of participants in these surveys with three multivariate taxometric procedures (MAMBAC, MAXEIG, and L‐Mode) after summing responses on the surveys into three indicators of positive psychosis. Results: Taxometric results tended to support a dimensional, rather than taxonic structure for psychotic experiences. In the CPES, all taxometric methods produced graphical and numerical support for a dimensional structure. In the NCS, MAMBAC appeared to slightly support a taxonic structure, whereas MAXEIG and L‐Mode supported a dimensional structure. Conclusion: There appears to be a dimensional distribution of psychotic experiences in the general population. This supports the incorporation of dimensional representations of psychotic symptoms in the current diagnostic system.     

Correlation between attenuated psychotic experiences and depressive symptoms among Japanese students

Aims: To examine the emergence of attenuated psychotic experiences, self-disturbance or affective symptoms among younger subjects in the general population and to investigate the intergroup differences on each symptom between adolescents and post-adolescents. Methods: A total of 781 participants, 496 university students (mean age: 19.3 ± 1.1 years) and 285 high school students (mean age: 16.0 ± 0.3 years), were administered self-reported questionnaires. Psychotic prodromal symptoms were evaluated using the PRIME Screen-Revised (PS-R), a 12-item self-reported questionnaire. To measure the cognitive, emotional and physical symptoms associated with depression, the Zung Self-rating Depression Scale (ZSDS), a 20-item self-reported questionnaire, was administered. Results: There were no intergroup differences on the factor score of the PS-R, except the self-demarcation factor (post-adolescents > adolescents), whereas there were significant differences in the factor score of the ZSDS, except for the anxiety factor. Among the post-adolescents, the factors of the PS-R showed a moderate correlation to the cognitive factor on the ZSDS; among the adolescents, the PS-R factors showed a greater correlation to the anxiety factor on the ZSDS than other factors. There were no differences in the distribution of each item of the PS-R between the two groups. Conclusions: The disturbance of self results in difficulty to precisely objectify, especially among adolescents, which would induce more primitive reactions such as agitation, irritability or anxiety; probably, the self disturbance would become an explicit symptom from an implicit experience with advancing age of the subject. Although these data are only preliminary, they could explain the pathway of progression prior to the onset of psychosis, from disturbance within the self to exaggerated self-absorption.     

Dimensions of psychotic experiences among women in the general population

Full‐information factor analysis of ordinal data was employed to determine the factorial structure of the responses of 31,822 adult Swedish women to the 20 “positive” psychotic experience items of the Community Assessment of Psychic Experiences (CAPE) questionnaire. Five separable but correlated trait dimensions were found, reflecting Paranoia, Grandiosity, Magical Thinking, Delusions, and Hallucinations. High scores on any dimension were associated with a higher probability of questionnaire‐assessed lifetime major depressive episodes or generalized anxiety disorder, though Grandiosity was so only to a very small degree. Our results closely match previous findings among adolescents and young women, and demonstrate that psychotic experiences cannot be considered a single trait. Copyright © 2013 John Wiley & Sons, Ltd.     

Deconstructing the familiality of the emotive component of psychotic experiences in the general population

OBJECTIVE: Genetic and environmental influences on variation in distress associated with subclinical psychotic experiences were examined. METHOD: A total of 289 twin pairs filled in the Community Assessment of Psychic Experiences, a self-report instrument assessing subclinical positive and negative psychotic experiences and associated distress (distresspos and distressneg). Using structural equation modelling, univariate and bivariate models were fitted. RESULTS: Univariate model fitting showed genetic and non-shared environmental influences on both distresspos and distressneg. Bivariate model fitting showed that 52% of the correlation between the two phenotypes (r=0.46) was because of shared genes and that non-shared environmental factors accounted for 48% of the correlation. CONCLUSION: Liability to psychosis not only refers to the development of psychosis per se, but also to the liability to develop dysfunctional emotional appraisals. The emotive component of psychosis liability involves genetic transmission of a general, non-symptom-specific distress factor that may be a target for molecular genetic research.     

Loneliness and the psychosis continuum: a meta-analysis on positive psychotic experiences and a meta-analysis on negative psychotic experiences

Abstract

There is an increase in interest in the relationships between loneliness and psychosis. The notion of psychosis continuum implies that psychotic experiences extend from clinical populations with psychotic disorders to non-clinical populations. This meta-analytic review aimed to examine the respective associations of loneliness with positive and negative psychotic experiences along the psychosis continuum. A systematic database search was conducted and a total of 30 studies were included in the first meta-analysis and 15 studies were included in the second meta-analysis. There was a medium association between loneliness and positive psychotic experiences (r?=?0.302, p?<?0.001). In particular, the association between loneliness and paranoia was robust (r?=?0.448, p?<?0.001). The second meta-analysis revealed a medium association between loneliness and negative psychotic experiences (r?=?0.347, p?<?0.001). The associations between loneliness and both positive and negative psychotic experiences were found to be smaller among clinical than non-clinical samples. The above findings provided evidence for the associations between loneliness and the two core dimensions of psychotic experiences along the phenomenological continuum. Future research should examine the dynamics of these relationships in both clinical and non-clinical samples, preferably using a single-symptom approach.     

Subclinical psychotic experiences and cognitive functioning as a bivariate phenotype for genetic studies in the general population

OBJECTIVE: Cognitive deficits may be vulnerability markers for the development of schizophrenia. This study examined whether cognitive deficits are related to specific dimensions of subclinical psychotic experiences and whether associations between these variables are caused by additive genetic, common environmental and/or individual-specific environmental factors. METHOD: A general population sample of 298 female twin pairs completed the Community Assessment of Psychic Experiences and a neuropsychological test battery. Associations between subclinical positive and negative psychotic dimensions and neuropsychological factors (episodic memory and information processing speed) were examined. Univariate correlation and structural equation analyses were performed to explore the role of genetic and environmental factors in the phenotypes separately. Bivariate correlation and structural equation analyses were applied to examine the causes of association. RESULTS: There were significant correlations between information processing speed and both the positive (r=.11; p<.05) and the negative dimension (r=.10; p<.05). For the negative dimension and for speed of processing, the data suggested a model that included genetic factors. The observed phenotypic correlation between the negative dimension and information processing speed could be solely explained in terms of additive genetic factors. Although the comparison of the correlations for MZ and DZ pairs did not give a clear indication as to the underlying causes of the association, structural equation modelling suggested that the observed phenotypic correlation between the negative dimension and information processing speed could be solely explained in terms of additive genetic factors. CONCLUSION: Negative symptoms and information processing speed are associated at the subclinical level and this association appears to be influenced by genetic factors exclusively. Bivariate psychosis phenotypes may represent suitable candidates for molecular genetic studies in the general population.     

Childhood abuse as a risk factor for psychotic experiences

OBJECTIVE: To examine the hypothesis that individuals from the general population who report childhood abuse are at increased risk of developing positive psychotic symptoms. METHOD: Data were derived from a general population sample of 4045 subjects aged 18-64 years. First ever onset of positive psychotic symptoms at 2-year follow-up were assessed using the Composite International Diagnostic Interview and additional clinical interviews if necessary. Childhood abuse was assessed at baseline. RESULTS: Baseline reported childhood abuse predicted development of positive psychotic symptoms associated with need for care [odds ratio (OR) = 11.5, 95% CI 2.6-51.6]. This association remained after adjustment for demographic variables, reported risk factors and presence of any lifetime psychiatric diagnosis at baseline (OR = 7.3, 95% CI 1.1-49.0). CONCLUSION: The results suggest that early childhood trauma increases the risk for positive psychotic symptoms. This finding fits well with recent models that suggest that early adversities may lead to psychological and biological changes that increase psychosis vulnerability.     

Validity and reliability of the CAPE: a self-report instrument for the measurement of psychotic experiences in the general population

OBJECTIVE: General population longitudinal cohort studies have demonstrated the prognostic validity of self-reported psychotic experiences, but data on reliability and cross-validation with interview-based measures of these experiences are sparse. This study tested the reliability and validity of the Community Assessment of Psychic Experiences (CAPE42). METHOD: At baseline, the CAPE42 was used to measure the subclinical psychosis phenotype in a general population sample (n = 765). At follow-up (mean interval: 7.7 months), the Structured Interview for Schizotypy, Revised (SIS-R), the Brief Psychiatric Rating Scale (BPRS), and the CAPE42 were administered (n = 510). RESULTS: Baseline self-reported dimensions of psychosis were specifically and independently associated with their equivalent interview-based dimension at follow-up (standardized effect sizes of 0.4-0.5) and with their equivalent self-reported measure (standardized effect sizes of 0.6-0.8). CONCLUSION: The results indicate that self-reported dimensions of psychotic experiences in general population samples appear to be stable, reliable and valid.     

Self-report of family functioning and risk for psychotic disorders in male adolescents with behavioural disturbances

Objective: Previous studies indicate that a poor family environment might affect vulnerability for the later manifestation of psychotic illness. The current study aims to examine family functioning prior to the onset of psychosis. Method: Subjects were 42 948, 17‐year old males with behavioural disturbances who were asked about the functioning of their family by the Israeli Draft Board. Data on later psychiatric hospitalizations were obtained from a National Psychiatric Hospitalization Registry. Results: Poorer self‐reported family functioning was associated with greater risk for later hospitalization for psychosis [adjusted hazard ratio (HR) = 1.16, 95% CI = 1.05–1.27], with a trend in the same direction for schizophrenia (adjusted HR = 1.1, 95% CI = 0.98–1.24). Conclusion: In male adolescents with behavioural disturbances, perceived poorer family functioning is associated with increased risk for non‐affective psychotic disorders and schizophrenia. These data do not enable us to determine if perceived familial dysfunction increases vulnerability for psychosis, if premorbid behavioural abnormalities disrupt family life, or neither.