The effect of SARS-CoV-2 virus on resting-state functional connectivity during adolescence: Investigating brain correlates of psychotic-like experiences and SARS-CoV-2 related inflammation response

We first aimed to investigate resting-state functional connectivity (rs-FC) differences between adolescents exposed to SARS-CoV-2 and healthy controls. Secondly, the moderator effect of PLEs on group differences in rs-FC was examined. Thirdly, brain correlates of inflammation response during acute SARS-CoV-2 infection were investigated. Eighty-two participants aged between 14 and 24 years (SARS-CoV-2 (n = 35), controls (n = 47)) were examined using rs-fMRI. Seed-based rs-FC analysis was performed. The positive subscale of Community Assessment of Psychotic Experiences-42 (CAPE-Pos) was used to measure PLEs. The SARS-CoV-2 group had a lesser rs-FC within sensorimotor network (SMN), central executive network (CEN) and language network (LN), but an increased rs-FC within visual network (VN) compared to controls. No significant differences were detected between the groups regarding CAPE-Pos-score. However, including CAPE-Pos as a covariate, we found increased rs-FC within CEN and SN in SARS-CoV-2 compared to controls. Among the SARS-CoV-2 group, neutrophil/lymphocyte and thrombocyte*neutrophil/lymphocyte ratio was correlated with decreased/increased FC within DMN and SN, and increased FC within CEN. Our results showed rs-FC alterations within the SMN, CEN, LN, and VN among adolescents exposed to SARS-CoV-2. Moreover, changes in rs-FC associated with PLEs existed in these adolescents despite the absence of clinical changes. Furthermore, inflammation response was correlated with alterations in FC within the triple network system.

Understanding pathways from narcissistic grandiosity to psychotic-like experiences: Insights from the network analysis

It has been shown that narcissistic grandiosity and psychotic-like experiences (PLEs) may share the common psychological mechanisms, including impairments of metacognition, social cognition, cognitive biases, emotion regulation through fantasizing and dissociation. However, it remains unknown as to whether these mechanisms are associated with the occurrence of PLEs in people with narcissistic grandiosity. Therefore, in the present study, we approached a network analysis in order to investigate pathways from narcissistic grandiosity to PLEs taking into consideration the mediating effect of common psychological mechanisms. The study was based on a non-clinical sample of 1647 individuals, aged 18-35 years. Data were collected through self-reports administered in the online survey. There were no direct connections between narcissistic grandiosity and PLEs. However, four pathways connecting narcissistic grandiosity and PLEs through the effect of one mediating psychological mechanism were identified. These mechanisms covered external attribution biases, the need to control thoughts, social cognition, and emotion regulation through fantasizing. Among them, the shortest pathway led through the effects of external attribution biases. Age, gender, education and lifetime history of psychiatric treatment were included as covariates in a network analysis. Findings from this study indicate that higher levels of external attributions, the need to control thoughts, impairments of social cognition, and emotion regulation strategies based on fantasizing might be associated with the development of PLEs in people showing narcissistic grandiosity. These observations indicate potential targets for therapeutic approaches that aim to reduce the risk of developing comorbid psychopathology in people with grandiose narcissism traits.

Subclinical psychotic symptoms in Indian adults: Application of the Community Assessment of Psychic Experiences (CAPE)

BACKGROUND

The study investigated the psychometric properties of the Community, Assessment of Psychic Experiences (CAPE-42), a self-report instrument in Indians.

METHOD

CAPE-42 was translated in Hindi and tested on 312 Indian adults recruited online and through paper-pencil assessment. Confirmatory factor analysis (CFA) was employed to establish the factor structure of the positive, negative and depressive dimensions of CAPE-42: the bifactor model was tested to evaluate whether items converge into a major single factor defining psychotic-proneness in individuals. Latent class analysis (LCA) was conducted to identify subgroups with a different endorsement of subclinical psychotic symptoms.

, RESULTS

CAPE-Hindi showed good reliability (Cronbach's alpha>0.80). CFA confirmed, a good fit for the bifactor model, factor loading was acceptable for all items in the general factor (Omega-h =0.83) and explained the primary variance of the subscales. Residual variance was explained by the positive, negative and depressive factors (Omega H =0.33, 0.04 and 0.12, respectively). LCA identified three classes traceable, to the three dimensions; a low endorsement group (n = 155; 50 %); a less consistent, group with endorsement on positive and depressive items (n = 117; 38 %), and a high, endorsement group (n = 40;13 %).

CONCLUSION

Hindi CAPE-42 showed good reliability and factorial validity.

Polygenic risk for schizophrenia as a moderator of associations between childhood trauma and schizotypy

Recent evidence shows that genetic and environmental risk factors for psychotic disorders are associated with higher levels of schizotypy (or psychosis proneness) in the general population. However, little is known about how these risk factors interact. We specifically examined whether genetic loading for schizophrenia moderates the association between childhood trauma severity and schizotypy. Schizotypy was measured using the Schizotypal Personality Questionnaire (SPQ), and childhood trauma severity was measured with the Childhood Trauma Questionnaire (CTQ) among a total of 168 participants (comprising 51 healthy individuals, 56 diagnosed with schizophrenia, and 61 with bipolar disorder). Polygenic risk scores (PRS) for schizophrenia were calculated for all participants and examined as a potential moderator of associations between total scores on the CTQ and schizotypy total scores and dimensions (i.e., cognitive-perceptual, interpersonal, disorganised). Multiple linear regression models revealed associations between childhood trauma and all dimensions of schizotypy, but no associations between PRS and schizotypy. A significant interaction between PRS and childhood trauma was evident for the interpersonal and disorganised dimensions of schizotypy, as well as the total score, reflecting positive associations between childhood trauma severity and these two schizotypal dimensions, only for individuals with low or average PRS for schizophrenia. This suggests that trauma may be able to increase risk for psychosis independently of any genetic vulnerability. The present findings are consistent with the idea of several risk pathways for the development of psychotic disorders.

Examining subjective experience of aberrant salience in young individuals at ultra-high risk (UHR) of psychosis: A 1-year longitudinal study

Aberrant salience (AS) is considered as a predisposing factor in early psychosis. Although it has been frequently examined in the general population as a measure of vulnerability to psychotic disorder, empirical evidence on AS in prodromal phases of psychosis is still relatively scarce. Thus, the aims of this research were (1) to investigate any significant association of AS with functioning, psychopathology and treatment components of an "early intervention in psychosis" program in a sample of young community help-seekers at Ultra-High Risk (UHR) of psychosis along a 1-year follow-up period, and (2) to longitudinally monitor the stability of AS across the 1 year of follow-up. Participants (87 UHR), aged 13-35 years, completed the Aberrant Salience Inventory (ASI), the Comprehensive Assessment of At-Risk Mental States (CAARMS) and the brief version of the Schizotypal Personality Questionnaire (SPQ-B) at baseline and after the 1 year of follow-up. Spearman correlation analyses among psychopathological parameters and specialized treatment components were performed. A multiple linear regression analysis was also carried out. After a 1-year follow-up period, UHR subjects had a statistically relevant decrease in ASI total scores. This was significantly related to the number of individual cognitive-behavioral therapy (CBT) sessions and the number of family psychoeducational sessions offered to UHR participants and their family members during the same 12-month period. In conclusion, AS is clinically relevant in UHR individuals. However, it seems to improve over time along with the delivery of tailored, specialized psychosocial interventions for early psychosis.

Network analysis of psychotic manifestations among cocaine users

Psychotic experiences can be described along a continuum ranging from no psychotic experience at all, to clinical psychotic disorder. Any individual in the general population may encounter psychotic experiences under certain circumstances. Transient Cocaine Induced Psychotic Symptoms (TCIPS) are a well described model of such circumstances. Therefore, our aim was to use a network analysis to get a better knowledge on the architecture of previously described risk factors and how they contributed to two different measures of psychosis (psychosis proneness and transient cocaine induced psychotic symptoms) This study is a secondary analysis conducted among 180 cocaine users in addiction care centers in Paris and Paris suburb, who were evaluated with the PDI (Peters Delusion Inventory) and the SAPS-CIP (Scale for the Assessment of Psychotic Symptoms - Cocaine Induced Psychosis). Schizophrenia diagnosis was extracted from medical record. Relevant variables significantly associated with SAPS-CIP total score or PDI at the first step were included in a network analysis to better figurate their respective associations. The network centrality measures showed that the product preferentially used (crack vs cocaine) was related to TCIPS, psychosis proneness and, to a lesser extent, schizophrenia. Secondly, in this model TCIPS is a mediator between intensive cocaine use and psychosis proneness. Thirdly, this study refines the previous knowledge on heavy cannabis use being a risk factor for TCIPS. The observed link is not direct but mediated by psychosis proneness.

Dopamine D1 receptor availability is not associated with delusional ideation measures of psychosis proneness

The dopamine D1 receptor (D1R) is thought to play a role in psychosis and schizophrenia, however positron emission tomography studies comparing patients and controls have been inconsistent. To circumvent some of the limitations of clinical studies, such as antipsychotic exposure, an alternative approach is to examine subclinical psychotic symptoms within the general population, i.e. psychosis proneness traits. In this study, we investigated whether D1R availability is associated with delusional ideation in healthy controls, in four experiments, using [¹¹C]SCH23390 PET (n = 76) and psychometric questionnaires (n = 217). We performed exploratory analyses, direct self-replication, and confirmatory analyses using Bayesian statistical modelling. Collectively, we found strong evidence that there is little to no linear association between delusional ideation and D1R. If hypothesised changes in D1R in drug-naive psychosis patients can be confirmed, our results suggest that they may either occur at disease onset, or that they are associated with specific aspects of psychosis other than delusional ideation.

Schizotypy, social stress and the emergence of psychotic-like states - A case for benign schizotypy?

Schizotypy is a personality-organisation related to schizophrenia-liability as well as the emergence of psychotic symptoms and psychotic-like experiences (PLEs) in non-schizophrenic individuals. It has been suggested that some non-schizophrenic individuals may exhibit PLEs frequently, but in a fashion that is not distressing but life-enhancing ("benign schizotypy"). In schizophrenia and at-risk individuals, however, psychotic symptoms are not only distressing, but also triggered stress. To further investigate questions of causality and examine how PLEs may present as distressing symptoms in some individuals and as benign experiences in others, we explored how schizotypy-facets moderated PLEs-variability under experimentally induced social stress.We performed a standardised social stress-paradigm in 107 healthy adults (77 female, 30 male; average age 22,5 years), measuring changes in psychometrically assessed PLEs and the moderation of changes under stress through positive, negative and disorganised schizotypy. Results suggest two discrete effects: On the one hand, individuals high in disorganised and negative schizotypy showed stress-dependent increases in PLEs; without added effects of positive schizotypy. On the other, individuals low in negative and disorganised schizotypy showed higher levels of PLEs solely as a function of positive schizotypy but not stress. We discuss these findings in light of the fully-dimensional model of schizotypy and hypothesize that PLEs in individuals high in schizotypy-facets suggested to convey risk-for-schizophrenia (negative and disorganised) may reflect qualitatively different entities than PLEs in individuals with low values in these facets, but high expressions of positive schizotypy ("happy schizotypes"). Additionally, we emphasize the importance of not overlooking the disorganised schizotypy-facet in related research.

Selectively reduced contrast sensitivity in high schizotypy

Deficits in the ability to encode small differences in contrast between adjacent parts of an image (contrast sensitivity) are well documented in schizophrenic patients. In the present study, we sought to determine whether contrast sensitivity deficits reported in schizophrenic patients are also evident in those who exhibit high schizotypy scores in a typical (i.e., non-schizophrenic) population. Using the O-Life Questionnaire, we determined the effects of schizotypy on spatial (0.5, 2 and 8 c/deg) and spatiotemporal (0.5 and 8 c/deg at 0.5 and 8 Hz) contrast sensitivity in 73 young (18-26 years), majority female (n = 68) participants. We found differences in contrast sensitivity that were spatial, spatiotemporal and O-Life subscale specific. Spatial contrast sensitivity was significantly lower in high, compared to low schizotypes at low spatial frequencies (0.5 c/deg) in those who scored highly on the Unusual Experiences and Cognitive Disorganisation O-Life subscales. For moving stimuli, individuals with high scores on the Unusual Experiences subscale exhibited lower spatiotemporal contrast sensitivity for 0.5 and 8 c/deg patterns drifting at 8 Hz. Although the effects reported here were relatively small, this is the first report of reduced contrast sensitivity in schizotypy.

Odd and disorganized-Comparing the factor structure of the three major schizotypy inventories

Schizotypy is a personality-framework currently considered a comprehensive and useful construct in schizophrenia research and becoming ever more accepted within psychiatry. Thus, it is crucial to obtain a unifying and generally accepted means of its measuring. The three most commonly used psychometric schizotypy inventories, the Wisconsin Schizotypy Scales, Schizotypal Personality Questionnaire and Oxford-Liverpool Inventory of Feelings and Experiences were, however, built upon different theoretical schizotypy models, wherefore comparing results from studies that have used different inventories is difficult and sometimes questionable. Therefore, an analysis of all three inventories was conducted within the same sample of 327 healthy participants to illustrate the similarities and differences in factor structures. Results showed that findings are likely dependent on the used assessment instrument. A following item-level factor analysis was conducted to investigate the shared structure of all three inventories, in order to illustrate a framework interpretable as "common ground" between measures. This adjusted four-factor structure may be used to better aid comparisons between schizotypy-studies having used different inventories. At least, our findings illustrate the necessity of viewing individual results before the background of the theoretical framework of the respective measurement tool.

A positive-psychological intervention reduces acute psychosis-proneness

BACKGROUND

While individuals at ultra-risk for schizophrenia are characterized by high negative/disorganised but low positive schizotypy, schizophrenia patients are usually high in all three schizotypy facets. Thus, avoiding increases in positive schizotypy in ultra-high risk individuals may constitute of form of schizophrenia-prevention. A possible method of reducing positive schizotypy could be Positive-Psychological intervention (PI).

METHODS

We present results from 2 independent studies, including a 12-month follow-up from study 1, using an easy-to-perform intervention based on Positive Psychology to reduce positive schizotypy.

RESULTS

A PI can significantly and sustainably reduce positive schizotypy compared to a placebo-condition. Furthermore, our results show very high response-rates to said intervention, with responsiveness to the intervention increasing significantly with disorganised schizotypic traits.

CONCLUSIONS

As especially disorganised schizotypy is of relevance for the risk of transition from high benign schizotypy to schizophrenia and is found most closely associated to familial schizophrenia-risk and highly elevated in at-risk mental states, our results are encouraging. We suggest, thus, that positive psychology can not only reduce positive schizotypy, but may be increasingly useful with rising schizophrenia-risk and, thus, be worthy of further investigation regarding it potential in schizophrenia-prevention.

The factor structure of the short form of the Wisconsin schizotypy scales

The Chapman psychosis-proneness scales-also known as Wisconsin schizotypy scales (WSS)-are among the most used tools to measure schizotypy. The factor structure of the short-form WSS was investigated in a mixed sample of patients with chronic mental disorders and of healthy subjects from the general population. One hundred patients with a chronic mental disorder were enrolled over a 6-month period. For each patient, two controls of same sex and similar age (±5 years) were enrolled; 131 accepted to take part in the study. The unidimensional, the correlated four-factor, the second-order two-factor models, and the bifactor model with two or four orthogonally independent factors of the short-form WSS were tested with confirmatory factor analysis. Good reliability of the short-form WSS was confirmed, as its capacity of differentiating people with and without schizotypy. The bifactor models were superior to other models. However, in both bifactor models the explained common variance (ECV) attributable to the general factor and the percentage of uncontaminated correlations (PUC) were too low to use a general summary score as a measure of a single latent schizotypy variable. Symptoms scores derived from the short-form WSS can be better appreciated within a multidimensional model of schizotypy.

Validation of the Chinese version of Community Assessment of Psychic Experiences (CAPE) in an adolescent general population

The Community Assessment of Psychic Experiences (CAPE) is a popular 42-item self-report assessment of psychosis proneness (PP) that has been widely-translated. However, there is as yet no validation of CAPE in non-Western languages. Here, we validated a Chinese translation of CAPE ("CAPE-C") in a young Chinese community sample. Factor analyses were employed in a sample of 660 individuals (mean age=18.63) to identify a culturally-sensitive factor structure for CAPE-C (Study 1). Since confirmatory factor analysis (CFA) suggested that CAPE-C did not follow the original factor structure, exploratory factor analysis and follow-up CFA were employed to establish an alternative structure, resulting in a 15-item "CAPE-C15" which retained a three-factor structure tapping positive, negative and depressive symptoms. To demonstrate the specificity of CAPE-C15 as a measure of PP, we conducted regression analyses to examine associations between CAPE-C15 dimensions and other measures of psychotic and depressive symptoms (Study 2). Results confirmed that CAPE-C15 dimensions showed specific associations with relevant symptom dimensions of other measures, but not with irrelevant ones. Finally, to aid interpretation of CAPE-C15 scores, Receiver Operating Characteristic analysis was conducted to establish a cut-off score that could indicate test-takers' need for clinical attention (Study 3). We found that a cut-off score of 8.18 on CAPE-C15 positive and negative symptom frequency and distress scores distinguished individuals whose PP was within normal ranges from those at psychometric high-risk (sensitivity: 78.6%; specificity: 77.7%). CAPE-C15 will likely prove relevant to researchers and healthcare providers who serve Chinese-speaking adolescents and young adults.

The impact of loneliness on paranoia: An experimental approach

BACKGROUND AND OBJECTIVES

Loneliness is a common problem in patients with schizophrenia, and may be particularly linked with persecutory ideation. Nevertheless, its role as a potential risk factor in the formation and maintenance of persecutory delusions is largely unexplored.

METHODS

Loneliness was experimentally manipulated using a false-feedback paradigm in a non-clinical sample (n = 60). Change in state paranoia was compared between the induction of increased loneliness, the induction of reduced loneliness and a control condition. Distinct associations between pre-post scores of loneliness and state paranoia were examined at three (medium/high/low) levels of proneness to psychosis across the experimental conditions.

RESULTS

Reduction of loneliness was associated with a significant reduction of present paranoid beliefs, while induction of loneliness lead to more pronounced paranoia on trend significance level. Moreover, proneness to psychosis significantly moderated the impact of loneliness on paranoia. Persons with a pronounced level of proneness to psychosis showed a stronger reduction of paranoid beliefs as a consequence of a decrease in loneliness, than less prone individuals.

LIMITATIONS

A limitation is the small size of our sample, which may have limited the power to detect significant within-group changes in state paranoia in the high-loneliness condition and changes in loneliness in the low-loneliness condition.

CONCLUSIONS

The findings support the feasibility of the experimental design to manipulate loneliness and suggest that loneliness could be a cause of paranoia. However, the findings need to be confirmed in high risk samples to draw conclusions about the role of loneliness in the genesis of clinically relevant levels of paranoia and derive implications for cognitive behaviour therapy.

Association between RGS4 variants and psychotic-like experiences in nonclinical individuals

The psychosis phenotype is expressed across a continuum known as schizotypy, which ranges from personality variation through subclinical symptoms to severe psychopathology. The study of subclinical manifestations in non-affected individuals minimizes confounding factors associated with the clinical phenotype and facilitates the differentiation of dimension-specific etiological mechanisms. The aim of the present study was to investigate the association between the variation in the regulator of G-protein signaling 4 (RGS4) gene, a putative candidate gene for psychosis previously associated with schizophrenia endophenotypes, and psychotic-like experiences (PLEs). In total, 808 healthy individuals completed the community assessment of psychic experiences (CAPE) to measure positive and negative PLEs and provided a DNA sample. Two RGS4 single-nucleotide polymorphisms (SNPs) (rs951436 [SNP4] and rs2661319 [SNP18]) were genotyped. Analyses of covariance (ANCOVA) were used to explore the association of positive and negative PLEs with RGS4 variation. Our results showed associations of positive and negative PLEs with the two polymorphisms studied: subjects with the T allele (SNP4) and the A allele (SNP18) had higher scores on both the positive and the negative dimensions. Haplotypic analyses supported these results, showing the highest scores in those with the TA haplotype (SNP4-SNP18). The RGS4 variants might exert gene-specific modulating effects on psychosis proneness.

Childhood trauma, BDNF Val66Met and subclinical psychotic experiences. Attempt at replication in two independent samples

Childhood trauma exposure is a robust environmental risk factor for psychosis. However, not all exposed individuals develop psychotic symptoms later in life. The Brain-derived neurotrophic factor (BDNF) Val66Met polymorphism (rs6265) has been suggested to moderate the psychosis-inducing effects of childhood trauma in clinical and nonclinical samples. Our study aimed to explore the interaction effect between childhood trauma and the BDNF Val66Met polymorphism on subclinical psychotic experiences (PEs). This was explored in two nonclinical independent samples: an undergraduate and technical-training school student sample (n = 808, sample 1) and a female twin sample (n = 621, sample 2). Results showed that childhood trauma was strongly associated with positive and negative PEs in nonclinical individuals. A BDNF Val66Met x childhood trauma effect on positive PEs was observed in both samples. These results were discordant in terms of risk allele: while in sample 1 Val allele carriers, especially males, were more vulnerable to the effects of childhood trauma regarding PEs, in sample 2 Met carriers presented higher PEs scores when exposed to childhood trauma, compared with Val carriers. Moreover, in sample 2, a significant interaction was also found in relation to negative PEs. Our study partially replicates previous findings and suggests that some individuals are more prone to develop PEs following childhood trauma because of a complex combination of multiple factors. Further studies including genetic, environmental and epigenetic factors may provide insights in this field.

Further examination of the factor structure of the Chapman Psychosis Proneness Scales (CPPS)

Results of recent analyses of the Chapman Psychosis Proneness Scales (CPPS) have been inconsistent with regard to their factor structure. This inconsistency has involved whether the Revised Social Anhedonia Scale (SocAnh) reflects only the negative or both the negative and positive dimensions of schizotypy, along with the degree of correlation between these two dimensions. In the present study, confirmatory factor analysis was used to compare models created by Chan et al. and Kwapil et al.; a third model was constructed based on adjustments to these prior models and consideration of the schizotypy construct. Following Kwapil et al., our model allowed for bi-loading of SocAnh scale, but eliminated the correlation between positive and negative factors. Although fitness for each of the previously offered models was adequate, RMSEA and chi-square indicators suggested ideal fit for the model proposed by Kwapil and our new model, which redirects variance thought to be shared among the positive and negative dimensions to its specific source, SocAnh. The implications of these competing models with regard to our conceptualization of schizotypy are addressed. It is suggested that the cross loading of SocAnh reflects the notion of social anhedonia as the core of schizotypic personality organization.

Brain structural correlates of schizotypy and psychosis proneness in a non-clinical healthy volunteer sample

Schizotypal traits are phenotypic risk factors for schizophrenia, associated with biological changes across a putative schizophrenia spectrum. In this study, we tested the hypothesis that brain structural changes in key brain areas relevant to this spectrum (esp. medial and lateral prefrontal cortex) would vary across different degrees of schizotypal trait expression and/or phenotypic markers of psychosis proneness in healthy non-clinical volunteers. We analysed high-resolution 3Tesla magnetic resonance images (MRI) of 59 healthy volunteers using voxel-based morphometry (VBM), correlating grey matter values to the positive and negative symptom factors of the schizotypal personality questionnaire (SPQ, German version) and a measure of psychosis proneness (community assessment of psychic experiences, CAPE). We found positive correlations between positive SPQ dimension and bilateral inferior and right superior frontal cortices, and positive CAPE dimension and left inferior frontal cortex, as well as CAPE negative dimension and right supplementary motor area (SMA) and left inferior parietal cortex. However, only the positive correlation of the right precuneus with negative schizotypy scores was significant after FWE correction for multiple comparisons. Our findings confirm an effect of schizotypal traits and psychosis proneness on brain structure in healthy subjects, providing further support to a biological continuum model.

The dimensional structure of short forms of the Wisconsin Schizotypy Scales

The Wisconsin Schizotypy Scales (WSS) are widely used for assessing schizotypy. Confirmatory factor analysis (CFA) indicates that a two-factor structure, positive and negative schizotypy, underlies these scales. Recently developed 15-item short forms of the WSS demonstrated good reliability and validity. This study examined the factor structure underlying the short-form WSS. Consistent with the original scales, CFA on three large samples (n=6137, 2171, and 2292, respectively) indicated that a two-factor model with positive and negative dimensions provided better fit than a generic schizotypy model for the short-form WSS. The short-form dimensions correlated highly with the original scale dimensions and displayed good stability across 10weeks. Preliminary construct validity was demonstrated through associations with interview and questionnaire measures of psychopathology, functioning, and personality comparable to those found with the original WSS. This is the first study examining the dimensional structure of the short WSS and the validity of these dimensions. The findings support the multidimensional nature of schizotypy and the appropriateness of dimensions derived from the short-form WSS.

Cognitive biases mediate the relationship between temperament and character and psychotic-like experiences in healthy adults

Psychotic-like experiences (PLEs) are frequently reported in the general population. Healthy individuals reporting PLEs have a similar personality profile to people with psychosis; however, the mechanisms by which personality influences PLEs are unclear. This study tests the hypothesis that cognitive biases mediate the relationship between two dimensions of personality (i.e. temperament and character) and positive and negative PLEs. Two hundred and ninety-six healthy participants were assessed using the Community Assessment of Psychic Experiences scale, the Temperament and Character Inventory and the Davos Scale for Cognitive Biases. We performed multiple stepwise regression analysis and mediation analysis according to Baron and Kenny׳s method. Harm-avoidance and self-directedness personality dimensions significantly predicted PLEs frequency. High self-transcendence and lower cooperativeness predicted positive PLEs. Cognitive biases were significant mediators in relationships between temperament, character and both positive and negative PLEs. In particular, attention to threat and external attribution biases fully mediate the relationship between cooperativeness and positive PLEs. Other cognitive biases partially mediate the relationships between self-transcendence and positive PLEs and self-directedness, harm-avoidance and negative PLEs. Our study tentatively suggests that personality may influence PLEs via the cognitive bias pathway.

Pattern classification of brain activation during emotional processing in subclinical depression: psychosis proneness as potential confounding factor

We used Support Vector Machine (SVM) to perform multivariate pattern classification based on brain activation during emotional processing in healthy participants with subclinical depressive symptoms. Six-hundred undergraduate students completed the Beck Depression Inventory II (BDI-II). Two groups were subsequently formed: (i) subclinical (mild) mood disturbance (n = 17) and (ii) no mood disturbance (n = 17). Participants also completed a self-report questionnaire on subclinical psychotic symptoms, the Community Assessment of Psychic Experiences Questionnaire (CAPE) positive subscale. The functional magnetic resonance imaging (fMRI) paradigm entailed passive viewing of negative emotional and neutral scenes. The pattern of brain activity during emotional processing allowed correct group classification with an overall accuracy of 77% (p = 0.002), within a network of regions including the amygdala, insula, anterior cingulate cortex and medial prefrontal cortex. However, further analysis suggested that the classification accuracy could also be explained by subclinical psychotic symptom scores (correlation with SVM weights r = 0.459, p = 0.006). Psychosis proneness may thus be a confounding factor for neuroimaging studies in subclinical depression.