The measurement invariance of schizotypy in Europe.

The short version of the Oxford-Liverpool Inventory of Feelings and Experiences (sO-LIFE) is a widely used measure assessing schizotypy. There is limited information, however, on how sO-LIFE scores compare across different countries. The main goal of the present study is to test the measurement invariance of the sO-LIFE scores in a large sample of non-clinical adolescents and young adults from four European countries (UK, Switzerland, Italy, and Spain). The scores were obtained from validated versions of the sO-LIFE in their respective languages. The sample comprised 4190 participants (M=20.87 years; SD=3.71 years). The study of the internal structure, using confirmatory factor analysis, revealed that both three (i.e., positive schizotypy, cognitive disorganisation, and introvertive anhedonia) and four-factor (i.e., positive schizotypy, cognitive disorganisation, introvertive anhedonia, and impulsive nonconformity) models fitted the data moderately well. Multi-group confirmatory factor analysis showed that the three-factor model had partial strong measurement invariance across countries. Eight items were non-invariant across samples. Significant statistical differences in the mean scores of the s-OLIFE were found by country. Reliability scores, estimated with Ordinal alpha ranged from 0.75 to 0.87. Using the Item Response Theory framework, the sO-LIFE provides more accuracy information at the medium and high end of the latent trait. The current results show further evidence in support of the psychometric proprieties of the sO-LIFE, provide new information about the cross-cultural equivalence of schizotypy and support the use of this measure to screen for psychotic-like features and liability to psychosis in general population samples from different European countries.

Schizotypal traits in adolescents: links to family history of psychosis and psychological distress.

OBJECTIVE: Studies in the general population report that unusual subjective experiences are relatively common. Such experiences have been conceptualized either as extreme personality traits or as vulnerability markers for psychosis, and often grouped under the expression "schizotypal experiences". This study investigates the heterogeneity of schizotypal traits using factor and latent class analysis. METHODS: One thousand and thirty-two adolescents were recruited for this study. Schizotypal experiences were assessed with the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE); psychological distress was assessed with the General Health Questionnaire (GHQ). Confirmatory Factorial Analysis (CFA) and Latent Class Analysis (LCA) were performed on the O-LIFE and on the association with the GHQ and demographic variables. RESULTS: CFA replicated the original 4-factor structure of the O-LIFE. Three latent classes (LC) of schizotypal features were identified: participants in LC1 (26% of the total sample) showed minimal level of item endorsement; LC2 accounted for 52% of the sample and showed overall higher item endorsement compared to LC1, especially for disorganization and positive signs of schizotypy, but not for negative affective items. LC3 (22%) showed an overall higher level of item endorsement across schizotypal dimensions, and positive association with psychological distress and family history of psychosis. DISCUSSION: Different latent class of schizotypal features can be empirically defined in adolescent community samples. The most extreme class is defined not only by a profile of higher positive replies to the items, but also by anhedonia, high psychological distress, and family history of psychosis. These findings can inform prevention research in schizophrenia.

Ethnicity, violent offending, and vulnerability to schizophrenia: a pilot study.

Previous research has highlighted increased risk for schizophrenia in Afro-Caribbeans as well as over-representation in the prison population. This small-scale study examined the relationship between criminality, ethnicity, and psychosis-proneness in a male prison sample. Twenty British Caucasian and 20 Afro-Caribbean prisoners were divided into equal sub-groups of violent and non-violent offenders. Participants completed measures of schizotypy, delusional ideation, and hostility. Afro-Caribbean offenders scored more highly on negative schizotypy and delusional ideation than their Caucasian counterparts. Violent offenders scored more highly on the positive symptoms of schizotypy than non-violent prisoners. Both ethnicity and violent offending may be relevant factors when considering vulnerability to psychosis in the offending population.