The structure of schizotypal personality traits: a cross-national study.

BACKGROUND: Schizotypal traits are considered a phenotypic-indicator of schizotypy, a latent personality organization reflecting a putative liability for psychosis. To date, no previous study has examined the comparability of factorial structures across samples originating from different countries and cultures. The main goal was to evaluate the factorial structure and reliability of the Schizotypal Personality Questionnaire (SPQ) scores by amalgamating data from studies conducted in 12 countries and across 21 sites. METHOD: The overall sample consisted of 27 001 participants (37.5% males, n = 4251 drawn from the general population). The mean age was 22.12 years (s.d. = 6.28, range 16-55 years). The SPQ was used. Confirmatory factor analysis (CFA) and Multilevel CFA (ML-CFA) were used to evaluate the factor structure underlying the SPQ scores. RESULTS: At the SPQ item level, the nine factor and second-order factor models showed adequate goodness-of-fit. At the SPQ subscale level, three- and four-factor models displayed better goodness-of-fit indices than other CFA models. ML-CFA showed that the intraclass correlation coefficients values were lower than 0.106. The three-factor model showed adequate goodness of fit indices in multilevel analysis. The ordinal α coefficients were high, ranging from 0.73 to 0.94 across individual samples, and from 0.84 to 0.91 for the combined sample. CONCLUSIONS: The results are consistent with the conceptual notion that schizotypal personality is a multifaceted construct and support the validity and utility of SPQ in cross-cultural research. We discuss theoretical and clinical implications of our results for diagnostic systems, psychosis models and cross-national mental health strategies.

An updated and conservative systematic review and meta-analysis of epidemiological evidence on psychotic experiences in children and adults: on the pathway from proneness to persistence to dimensional expression across mental disorders.

BACKGROUND: The psychosis-proneness-persistence-impairment model of psychotic disorder incorporates notions of both phenomenological and temporal continuity (persistence) of psychotic experiences (PE), but not structural continuity. Specific testable propositions of phenomenological continuity and persistence are identified. Method Propositions are tested by systematic reviews of the epidemiology of PE, persistence of PE and disorder outcomes, and meta-analyses (including Monte Carlo permutation sampling, MCPS) of reported rates and odds ratios (ORs). RESULTS: Estimates of the incidence and prevalence of PE obtained from 61 cohorts revealed a median annual incidence of 2.5% and a prevalence of 7.2%. Meta-analysis of risk factors identified age, minority or migrant status, income, education, employment, marital status, alcohol use, cannabis use, stress, urbanicity and family history of mental illness as important predictors of PE. The mode of assessment accounted for significant variance in the observed rates. Across cohorts, the probability of persistence was very strongly related to the rate of PE at baseline. Of those who report PE, ∼20% go on to experience persistent PE whereas for ∼80%, PE remit over time. Of those with baseline PE, 7.4% develop a psychotic disorder outcome. CONCLUSIONS: Compelling support is found for the phenomenological and temporal continuity between PE and psychotic disorder and for the fundamental proposition that this relationship is probabilistic. However, imprecision in epidemiological research design, measurement limitations and the epiphenomenological nature of PE invite further robust scrutiny of the continuity theory.

Development and evaluation of an enzyme-linked immunosorbent assay for use in the detection of bovine tuberculosis in cattle.

As a consequence of continued spillover of Mycobacterium bovis into cattle from wildlife reservoirs and increased globalization of cattle trade with associated transmission risks, new approaches such as vaccination and novel testing algorithms are seriously being considered by regulatory agencies for the control of bovine tuberculosis. Serologic tests offer opportunities for identification of M. bovis-infected animals not afforded by current diagnostic techniques. The present study describes assay development and field assessment of a new commercial enzyme-linked immunosorbent assay (ELISA) that detects antibody to M. bovis antigens MPB83 and MPB70 in infected cattle. Pertinent findings include the following: specific antibody responses were detected at ∼90 to 100 days after experimental M. bovis challenge, minimal cross-reactive responses were elicited by infection/sensitization with nontuberculous Mycobacterium spp., and the apparent sensitivity and specificity of the ELISA with naturally infected cattle were 63% and 98%, respectively, with sensitivity improving as disease severity increased. The ELISA also detected infected animals missed by the routine tuberculin skin test, and antibody was detectable in bulk tank milk samples from M. bovis-infected dairy herds. A high-throughput ELISA could be adapted as a movement, border, or slaughter surveillance test, as well as a supplemental test to tuberculin skin testing.

A systematic review and meta-analysis of the psychosis continuum: evidence for a psychosis proneness-persistence-impairment model of psychotic disorder.

A systematic review of all reported incidence and prevalence studies of population rates of subclinical psychotic experiences reveals a median prevalence rate of around 5% and a median incidence rate of around 3%. A meta-analysis of risk factors reveals associations with developmental stage, child and adult social adversity, psychoactive drug use, and also male sex and migrant status. The small difference between prevalence and incidence rates, together with data from follow-up studies, indicates that approximately 75-90% of developmental psychotic experiences are transitory and disappear over time. There is evidence, however, that transitory developmental expression of psychosis (psychosis proneness) may become abnormally persistent (persistence) and subsequently clinically relevant (impairment), depending on the degree of environmental risk the person is additionally exposed to. The psychosis proneness-persistence-impairment model considers genetic background factors impacting on a broadly distributed and transitory population expression of psychosis during development, poor prognosis of which, in terms of persistence and clinical need, is predicted by environmental exposure interacting with genetic risk.

Automatic hypermnesia and impaired recollection in schizophrenia.

Evidence from studies of nonmnemonic automatic cognitive processes provides reason to expect that schizophrenia is associated with exaggerated automatic memory (implicit memory), or automatic hypermnesia. Participants with schizophrenia (n = 22) and control participants (n = 26) were compared on word stem completion (WSC) and list discrimination (LD) tasks administered using the process dissociation procedure. Unadjusted, extended measurement model and dual-process signal-detection methods were used to estimate recollection and automatic memory indices. Schizophrenia was associated with automatic hypermnesia on the WSC task and impaired recollection on both tasks. Thought disorder was associated with even greater automatic hypermnesia. The absence of automatic hypermnesia on the LD task was interpreted with reference to the neuropsychological bases of context and content memory.

The Profile of Functional Impairment in Communication (PFIC): a measure of communication impairment for clinical use.

This article describes the construction of the Profile of Functional Impairment in Communication (PFIC), a scale designed for the assessment of communication impairments following traumatic brain injury. The measure comprises 10 feature summary scales, assessing severity of impairment, and 84 specific behaviour items, assessing the frequency of specific communication impairments. To assess the psychometric properties of the scale, videotaped dyadic social interactions of 20 patients with traumatic brain injury were rated by eight trained raters. The feature summary scales were found to have acceptable inter-rater reliabilities, and high concurrent validity and internal consistency. Four case descriptions are presented to illustrate the clinical application of the PFIC. It is concluded that the PFIC is a useful measure for the identification of specific communication impairments in clinical practice.

Influence of asbestos fibers on collagen and prostaglandin production in fibroblast and macrophage co-cultures.

The interaction of fibroblasts, macrophages, and crocidolite asbestos fibers was studied in cell culture. We determined the effects of co-cultivation and asbestos fibers on collagen, total protein, and PG production. The co-cultivation of guinea pig alveolar macrophages and fetal lung fibroblasts resulted in a 155% increase in protein and a 31% increase in collagen production above fibroblast controls. The collagen was derived exclusively from the fibroblasts. Although total protein production was derived predominantly from the fibroblasts, the macrophages in co-culture also contributed to the protein levels. The addition of asbestos fibers to fibroblast cultures resulted in a decrease in collagen and total protein production. The addition of asbestos fibers to fibroblast and macrophage co-cultures prevented the enhancement of collagen production and limited the increase in protein production above fibroblast controls. PGE2, PGI2, and TXA2 were measured in macrophage and fibroblast cultures. Very low, almost undetectable PG production was observed under basal conditions by either cell type alone or in co-culture. Bradykinin induced release of these PGs in fibroblast but not macrophage cultures. This release was enhanced in co-cultures. Asbestos fibers, when added to the co-cultures caused a significant increase in the release of PGs, particularly PGE2. PGE2 is known to inhibit collagen and total protein production by fibroblasts. The increased release of PGs in asbestos-treated co-cultures may have contributed to the described asbestos suppression of collagen production