Confirmatory factor analysis of psychotic-like experiences in a general population sample

A cross-national investigation of psychosis-like experiences in five European countries included in the E-CLECTIC study: Psychometric challenges in studying their measurement

BACKGROUND

Psychotic-like experiences (PLEs) are subtle, subclinical perturbations of perceptions and thoughts and are common in the general population. Their characterisation and unidimensionality are still debated.

METHODS

This study was conducted by the Electronic-halluCinations-Like Experiences Cross-culTural International Consortium (E-CLECTIC) and aimed at measuring the Community Assessment of Psychic Experiences (CAPE) factorial structure across five European countries (Belgium; Czech Republic, Germany; Greece, and Spain) and testing the adequacy of the unidimensional polytomous Rasch model of the tool via Partial Credit Model (PCM) of the CAPE to detect people with a high risk for developing psychosis.

RESULTS

The sample included 1461 participants from the general population. The factorial analysis confirmed the best fit for the bifactor implementation of the three-factor model, including the positive, negative and depressive dimensions and a general factor. Moreover, the unidimensional polytomous Rasch analysis confirmed that CAPE responses reflected one underlying psychosis proneness.

CONCLUSIONS

The study proved that the CAPE measures a single latent dimension of psychosis-proneness. The CAPE might help locate and estimate psychosis risk and can be used as a screening tool in primary care settings/education settings.

Factor and network analysis of psychosis-like experiences and depressive symptoms in a sample of Finnish adolescents entering psychiatric services

AIM

Psychosis-Like Experiences (PLEs) and depressive symptoms are correlated in clinical adolescent populations. However, symptom-level associations between the two phenomena are not clear.

METHODS

We analysed factor structures of a PLE instrument, the Prodromal Questionnaire-Brief (PQ-B), based on dimensions of positive symptoms of schizophrenia, and a depression measurement instrument, the Beck Depression Inventory (BDI-21A) and performed a network analysis of item-level associations between the two measures. The sample consisted of 417 adolescents (range 13-18 years of age, mean 14.9 years, 72.4% females) entering secondary psychiatric services at Helsinki metropolitan area, Finland.

RESULTS

Confirmatory factor analysis resulted in adequately fitting 2-factor solution, one for PQ-B and one for BDI-21, with a strong correlation coefficient of 0.605 between the two factors. In the network analysis, PQ-B and BDI-21 both formed their own clusters, and two significant pathways were estimated between PQ-B and BDI-21 clusters: 1. the association between paranoid thinking and distorted body image, and 2. the association between somatic preoccupation and worry about problems of one's mind.

CONCLUSIONS

Even though on a general, factor level, PLEs and depressive symptoms were strongly correlated, unique associations between symptoms of the two constructs were sparse. These findings should be considered in the psychiatric assessment and in the care of adolescents.

Comparing two measures of schizotypy and their relationship with psychological distress in British university students

AIMS

Schizotypy reflects the vulnerability to schizophrenia in the general population. Different questionnaires have been developed to measure aspects of schizotypy. Higher schizotypy scores have also been linked with depression, anxiety, and stress sensitivity. Here we examine the associations of schizotypy with symptoms of depression and anxiety in a sample of university students, using two different measures (N = 271).

METHODS

A series of confirmatory factor analyses was used to examine two distinct and frequently employed measures of schizotypy: the Community Assessment of Psychic Experiences (CAPE), and the Schizotypy Personality Questionnaire (SPQ). We assessed their relationship with each other and their predictive validity for anxiety, depression, and stress sensitivity.

RESULTS

Our results indicated the brief 7-factor SPQ (SPQ-BR) factor solution for the SPQ and the 15-item and 3 factor solution for the CAPE (i.e., CAPE-P15) as best fitting models. Particularly the CAPE dimension of persecutory ideation was a strong predictor of anxiety, depression, and stress sensitivity, whereas the SPQ dimensions of no close friends and social anxiety predicted psychological distress and stress in our student sample.

CONCLUSIONS

Our findings extend earlier work in general and patient samples and point to the importance of understanding the contribution of particularly positive schizotypy symptoms and different interpersonal aspects to psychological distress.

Autistic Symptoms and Social Functioning in Psychosis: A Network Approach

Psychotic and autistic symptoms are related to social functioning in individuals with psychotic disorders (PD). The present study used a network approach to (1) evaluate the interactions between autistic symptoms, psychotic symptoms, and social functioning, and (2) investigate whether relations are similar in individuals with and without PD. We estimated an undirected network model in a sample of 504 PD, 572 familial risk for psychosis (FR), and 337 typical comparisons (TC), with a mean age of 34.9 years. Symptoms were assessed with the Autism Spectrum Quotient (AQ; 5 nodes) and the Community Assessment of Psychic Experiences (CAPE; 9 nodes). Social functioning was measured with the Social Functioning Scale (SFS; 7 nodes). We identified statistically significant differences between the FR and PD samples in global strength (P < .001) and network structure (P < .001). Our results show autistic symptoms (social interaction nodes) are negatively and more closely related to social functioning (withdrawal, interpersonal behavior) than psychotic symptoms. More and stronger connections between nodes were observed for the PD network than for FR and TC networks, while the latter 2 were similar in density (P = .11) and network structure (P = .19). The most central items in strength for PD were bizarre experiences, social skills, and paranoia. In conclusion, specific autistic symptoms are negatively associated with social functioning across the psychosis spectrum, but in the PD network symptoms may reinforce each other more easily. These findings emphasize the need for increased clinical awareness of comorbid autistic symptoms in psychotic individuals.

Do you like cliff-hangers? Objective versus subjective need for closure in the schizophrenia spectrum

Need for closure (NFC) is a cognitive bias that has been implicated in the pathogenesis of delusions. A general population sample (N = 1465) was dichotomized into high versus low schizotypal participants and matched based on core social demographic characteristics (each n = 98). For the first time, we aimed at capturing NFC subjectively (with the NFC Scale) and objectively with a new experimental paradigm, the Ambiguous Movie Scene Task. In this task, participants viewed video scenes with either open or closed endings (i.e., high or low ambiguity) and rated their (emotional) reactions to the clips. Open endings were expected to lead to more frustration (i.e., due to increased need for closure) and to induce greater eagerness to learn about the possible resolution among those high on positive schizotypy. High schizotypal individuals displayed higher scores on the NFC Scale than low schizotypal individuals. Contrary to our expectations, high schizotypal participants did not recognize video scenes with open endings as ambiguous and were less eager to learn about a possible resolution than low schizotypal individuals. In the Ambiguous Movie Scene Task, high schizotypal individuals showed evidence of a jumping to conclusions bias rather than frustration over unresolved storylines. We found an overall stronger emotional response in schizotypal participants and overconfidence in their judgments. The NFC Scale and selected scores of the new task correlated moderately. The study corroborates earlier evidence for a dissociation between objective and subjective biases in the psychosis spectrum.

The Community Assessment of Psychic Experiences-Positive scale (CAPE-P15) accurately classifies and differentiates psychotic experience levels in adolescents from the general population

Background

There is increasing interest in studying psychotic symptoms in non-clinical populations, with the Community Assessment of Psychic Experiences-Positive scale (CAPE-P15) being one of the self-screening questionnaires used most commonly for this purpose. Further research is needed to evaluate the ability of the scale to accurately identify and classify positive psychotic experiences (PE) in the general population.

Aim

To provide psychometric evidence about the accuracy of the CAPE-P15 for detecting PE in a sample of Chilean adolescents from the general population and classifying them according to their PE severity levels.

Method

We administered the CAPE-P15 to a general sample of 1594 students aged 12 to 19. Based on Item Response Theory (IRT), we tested the accuracy of the instrument using two main parameters: difficulty and discrimination power of the 15 items.

Results

We found that the scale provides very accurate information about PE, particularly for high PE levels. The items with the highest capability to determine the presence of the latent trait were those assessing perceptual anomalies (auditory and visual hallucinations), bizarre experiences (a double has taken the place of others; being controlled by external forces), and persecutory ideation (conspiracy against me).

Conclusions

The CAPE-P15 is an accurate and suitable tool to screen PE and to accurately classify and differentiate PE levels in adolescents from the general population. Further research is needed to better understand how maladaptive psychological mechanisms influence relationships between PE and suicidal ideation (SI) in the general population.

Three types of psychotic-like experiences in youth at clinical high risk for psychosis

BACKGROUND

 A fully dimensional model of psychosis implies that psychotic-like experiences (PLEs) connect the entire psychosis spectrum. Three types of self-reported PLEs-persecutory ideation, bizarre experiences, and perceptual abnormalities-are commonly found in the general population. This study assessed the construct, predictive, and incremental validity of self-reported PLEs in youth at clinical high risk for psychotic disorders (CHR).

METHODS

 Self-report data on PLEs (community assessment of psychic experiences; CAPE) were collected from 105 CHR youth (m_age = 19.3). Interview measures of attenuated psychotic symptoms and self-report measures of psychosis proneness, depression, and anxiety were collected at baseline and 12-month follow-up (n = 70 at follow-up). Factor, cross-sectional, and longitudinal analyses examined relationships between study variables.

RESULTS

 Self-reported PLEs were best represented by the same three factors found in the general population: persecutory ideation, bizarre experiences, and perceptual abnormalities. Cross-sectionally, PLEs-particularly persecutory ideation-correlated with interview-rated attenuated psychotic symptoms and self-reported psychosis proneness, depression, and anxiety. Longitudinally, baseline PLEs trended toward predicting 12-month change in positive attenuated psychotic symptoms (r = .29, p_FDR = .058). Incrementally, baseline PLEs predicted 12-month change in positive and disorganized symptoms, when accounting for the effect of baseline positive symptoms and demographics.

CONCLUSIONS

 Three types of PLEs were valid in this CHR sample. Self-reported PLEs may be used not only to screen individuals for inclusion in the CHR classification, but also to characterize individuals within this population. Self-reported PLEs may help to forecast which CHR individuals will progress toward psychotic illness.

Cultural differences in positive psychotic experiences assessed with the Community Assessment of Psychic Experiences-42 (CAPE-42): a comparison of student populations in the Netherlands, Nigeria and Norway

BACKGROUND

Previous studies have suggested that culture impacts the experience of psychosis. The current study set out to extend these findings by examining cultural variation in subclinical positive psychotic experiences in students from The Netherlands, Nigeria, and Norway. Positive psychotic experiences were hypothesized to (i) be more frequently endorsed by, and (ii) cause less distress in Nigerian vs. Dutch and Norwegian students.

METHODS

Psychology students, aged 18 to 30 years, from universities in the Netherlands (n = 245), Nigeria (n = 478), and Norway (n = 162) were assessed cross-sectionally with regard to the frequency of subclinical positive psychotic experiences and related distress, using the Community Assessment of Psychic Experiences (CAPE-42). Multi-group confirmatory factor analysis and multivariate analysis of covariance were performed to assess measurement invariance of the positive symptom dimension (CAPE-Pos) and compare mean frequency and associated distress of positive psychotic experiences across study samples.

RESULTS

Only CAPE-Pos items pertaining to the dimensions 'strange experiences' and 'paranoia' met assumptions for (partial) measurement invariance. Frequencies of these experiences were higher in the Nigerian sample, compared to both the Dutch and Norwegian samples, which were similar. In addition, levels of experience-related distress were similar or higher in the Nigerian sample compared to respectively the Dutch and Norwegian samples.

CONCLUSION

Although positive psychotic experiences may be more commonly endorsed in non-Western societies, our findings do not support the notion that they represent a more benign, and hence less distressing aspect of human experience. Rather, the experience of psychotic phenomena may be just as, if not more, distressing in African than in European culture. However, observed differences in CAPE-Pos frequency and distress between samples from different cultural settings may partly reflect differences in the measure rather than in the latent trait. Future studies may therefore consider further cross-cultural adaptation of CAPE-42, in addition to explicitly examining cultural acceptance of psychotic phenomena, and environmental and other known risk factors for psychosis, when comparing and interpreting subclinical psychotic phenomena across cultural groups.

Psychotic Experiences and Related Distress: A Cross-national Comparison and Network Analysis Based on 7141 Participants From 13 Countries

Psychotic experiences (PEs) are common in the general population but do not necessarily reflect a risk status if they occur in relative isolation or are not distressing. Emerging evidence suggests that PEs might be experienced as more benign for individuals from collectivistic low- and middle-income countries (LAMIC) compared with individualistic high-income countries (HIC). The aim of this study was to determine whether: (1) self-reported PEs are less distressing in community samples from LAMIC than from HIC; (2) the network of PEs is significantly less connected in a sample from LAMIC than from HIC. Adults from 8 HIC (n = 4669) and 5 LAMIC (n = 2472) were compared. The lifetime frequency of PEs and related distress were assessed with the Community Assessment of Psychic Experiences. We analyzed the associations of PEs with distress and country type. The interconnection of PEs was visualized by a network analysis and tested for differences in global connection strengths. The average endorsement rates of PEs were significantly higher in LAMIC than in HIC (χ2 = 1772.87, P < .01, Φcramer = 0.50). There was a universal positive correlation between higher frequency of PEs and more distress, but the distress levels controlled for frequency were significantly higher in HIC (R2 = 0.11; b = 0.26; SE = 0.01; T = 17.68; P < .001). Moreover, the network of PEs was significantly less connected in LAMIC (S = 0.40, P < .05). The findings indicate that PEs are of less clinical relevance in LAMIC compared with HIC. The universal use of current high-risk criteria might thus not be adequate without consideration of associated distress and cultural values.

Cognitive profiles in childhood and adolescence differ between adult psychotic and affective symptoms: a prospective birth cohort study

BACKGROUND

Differences between verbal and non-verbal cognitive development from childhood to adulthood may differentiate between those with and without psychotic symptoms and affective symptoms in later life. However, there has been no study exploring this in a population-based cohort.

METHOD

The sample was drawn from the MRC National Survey of Health and Development, and consisted of 2384 study members with self-reported psychotic experiences and affective symptoms at the age of 53 years, and with complete cognitive data at the ages of 8 and 15 years. The association between verbal and non-verbal cognition at age 8 years and relative developmental lag from age 8 to 15 years, and both adult outcomes were tested with the covariates adjusted, and mutually adjusted for verbal and non-verbal cognition.

RESULTS

Those with psychotic experiences [thought interference (n = 433), strange experience (n = 296), hallucination (n = 88)] had lower cognition at both the ages of 8 and 15 years in both verbal and non-verbal domains. After mutual adjustment, lower verbal cognition at age 8 years and greater verbal developmental lag were associated with higher likelihood of psychotic experiences within individuals, whereas there was no association between non-verbal cognition and any psychotic experience. In contrast, those with case-level affective symptoms (n = 453) had lower non-verbal cognition at age 15 years, and greater developmental lag in the non-verbal domain. After adjustment, lower non-verbal cognition at age 8 years and greater non-verbal developmental lag were associated with higher risk of case-level affective symptoms within individuals.

CONCLUSIONS

These results suggest that cognitive profiles in childhood and adolescence differentiate psychiatric disease spectra.

Holding on to false beliefs: The bias against disconfirmatory evidence over the course of psychosis

BACKGROUND AND OBJECTIVES

The ability to integrate evidence into a reasoning process is crucial in order to react to changing information, e.g. to adapt one's beliefs according to new evidence or to generate new beliefs when facing better alternatives. Evidence integration ability is thus associated with belief flexibility. A specific bias of evidence integration, a bias against disconfirmatory evidence (BADE), can be found in patients with schizophrenia and has been linked to delusion development and maintenance. Knowledge about whether the BADE occurs already in risk constellations of psychosis can clarify its role in the pathogenesis of psychosis.

METHODS

This article reviews the current literature on BADE. Many studies demonstrate BADE over the course of illness, ranging from healthy controls with subclinical properties of schizotypy, over patients with at-risk mental states (ARMS) and patients with a first episode of psychosis to patients with chronic schizophrenia. These data allow a comparison of competences and deficits over the course of illness. Underlying mechanisms of BADE are discussed, including interrelations with neurocognitive performance and dopaminergic processes.

RESULTS

The BADE could be found in different phases of psychosis development and can be regarded as a cognitive marker of the beginning psychotic state.

LIMITATIONS

The presented findings are derived from independent cross-sectional studies. So far, no comprehensive longitudinal assessment has been published.

CONCLUSIONS

Treatments of metacognitive deficits in general and as early as in the ARMS might interfere with the cognitive pathogenesis of psychosis, and thereby ameliorate, postpone or even prevent the transition to psychosis.

The Reliability and Validity of Liu´s Self-Report Questionnaire for Screening Putative Pre-Psychotic States (BQSPS) in Adolescents

The usage of rigorous analyses based on contemporary methods to enhance psychometric properties of screening questionnaires aimed to address psychotic-like experiences (PLE) is currently being encouraged. The Brief Self-Report Questionnaire for Screening Putative Pre-psychotic States (BQSPS) is a recently created tool addressing PLE beyond attenuated positive symptoms (APS). Its psychometric properties as a screening tool for first step assessment seems to be adequate, but further research is needed to evaluate certain validity aspects, particularly its dimensionality, internal structure, and psychometric properties in different populations. We assessed the reliability, construct validity, and criterion validity of BQSPS in two samples: 727 adolescents aged 13-18 years, and 245 young adults aged 18-33 years. We used exploratory structural equation modeling (ESEM), confirmatory factor analysis (CFA), and Structural Equation Modeling (SEM). The original four-factor structure was not replicated. The best fit in adolescents was obtained by a structure of three-correlated factors: social anxiety (SA), negative symptoms (NS), and positive symptoms (PS). This structure was confirmed in young adult subjects. The three-factor model reached a predictive capability with suicidality as external criterion. PLE are represented by a three-factor structure, which is highly stable between adolescent and young-adult samples. Although the BQSPS seems to be a valid tool for screening PLE, its psychometric properties should be improved to obtain a more accurate measurement.