Are genetic risk factors for psychosis also associated with dimension-specific psychotic experiences in adolescence?

Psychosis has been hypothesised to be a continuously distributed quantitative phenotype and disorders such as schizophrenia and bipolar disorder represent its extreme manifestations. Evidence suggests that common genetic variants play an important role in liability to both schizophrenia and bipolar disorder. Here we tested the hypothesis that these common variants would also influence psychotic experiences measured dimensionally in adolescents in the general population. Our aim was to test whether schizophrenia and bipolar disorder polygenic risk scores (PRS), as well as specific single nucleotide polymorphisms (SNPs) previously identified as risk variants for schizophrenia, were associated with adolescent dimension-specific psychotic experiences. Self-reported Paranoia, Hallucinations, Cognitive Disorganisation, Grandiosity, Anhedonia, and Parent-rated Negative Symptoms, as measured by the Specific Psychotic Experiences Questionnaire (SPEQ), were assessed in a community sample of 2,152 16-year-olds. Polygenic risk scores were calculated using estimates of the log of odds ratios from the Psychiatric Genomics Consortium GWAS stage-1 mega-analysis of schizophrenia and bipolar disorder. The polygenic risk analyses yielded no significant associations between schizophrenia and bipolar disorder PRS and the SPEQ measures. The analyses on the 28 individual SNPs previously associated with schizophrenia found that two SNPs in TCF4 returned a significant association with the SPEQ Paranoia dimension, rs17512836 (p-value=2.57x10-4) and rs9960767 (p-value=6.23x10-4). Replication in an independent sample of 16-year-olds (N=3,427) assessed using the Psychotic-Like Symptoms Questionnaire (PLIKS-Q), a composite measure of multiple positive psychotic experiences, failed to yield significant results. Future research with PRS derived from larger samples, as well as larger adolescent validation samples, would improve the predictive power to test these hypotheses further. The challenges of relating adult clinical diagnostic constructs such as schizophrenia to adolescent psychotic experiences at a genetic level are discussed

Neural processing of criticism and positive comments from relatives in individuals with schizotypal personality traits

Objectives. High negative expressed emotion by family members towards schizophrenia patients increases the risk of subsequent relapse. The study aimed to determine whether individuals with high schizotypy (HS) and low schizotypy (LS) would differ in activation of brain areas involved in cognitive control when listening to relative criticism

Worries about being judged versus being harmed: Disentangling the association of social anxiety and paranoia with schizotypy

Paranoia is a dimension of clinical and subclinical experiences in which others are believed to have harmful intentions. Mild paranoid concerns are relatively common in the general population, and more clinically severe paranoia shares features with social anxiety and is a key characteristic of schizotypy. Given that subclinical manifestations of schizotypy and paranoia may predict the occurrence of more severe symptoms, disentangling the associations of these related constructs may advance our understanding of their etiology; however no known studies to date have comprehensively evaluated how paranoia relates to social anxiety and schizotypy. The current research sought to examine the association of paranoia, assessed across a broad continuum of severity, with 1) the positive and negative schizotypy dimensions and 2) social anxiety. Specifically, the study tested a series of six competing, a priori models using confirmatory factor analysis in a sample of 862 young adults. As hypothesized, the data supported a four-factor model including positive schizotypy, negative schizotypy, social anxiety, and paranoia factors, suggesting that these are distinct constructs with differing patterns of interrelationships. Paranoia had a strong association with positive schizotypy, a moderate association with social anxiety, and a minimal association with negative schizotypy. The results are consistent with paranoia being part of a multidimensional model of schizotypy and schizophrenia. Prior studies treating schizotypy and schizophrenia as homogenous constructs often produce equivocal or non-replicable results because these dimensions are associated with distinct etiologies, presentations, and treatment responses; thus, the present conceptualization of paranoia within a multidimensional schizotypy framework should advance our understanding of these constructs. © 2014 Horton et al

Schizotypy and Behavioural Adjustment and the Role of Neuroticism

In the present study the relationship between behavioural adjustment following cognitive conflict and schizotypy was investigated using a Stroop colour naming paradigm. Previous research has found deficits with behavioural adjustment in schizophrenia patients. Based on these findings, we hypothesized that individual differences in schizotypy, a personality trait reflecting the subclinical expression of the schizophrenia phenotype, would be associated with behavioural adjustment. Additionally, we investigated whether such a relationship would be explained by individual differences in neuroticism, a non-specific measure of negative trait emotionality known to be correlated with schizotypy. 106 healthy volunteers (mean age: 25.1, 60% females) took part. Post-conflict adjustment was measured in a computer-based version of the Stroop paradigm. Schizotypy was assessed using the Schizotypal Personality Questionnaire (SPQ) and Neuroticism using the NEO-FFI. We found a negative correlation between schizotypy and post-conflict adjustment (r = -.30, p<.01); this relationship remained significant when controlling for effects of neuroticism. Regression analysis revealed that particularly the subscale No Close Friends drove the effect. Previous findings of deficits in cognitive control in schizophrenia patients were extended to the subclinical personality expression of the schizophrenia phenotype and found to be specific to schizotypal traits over and above the effects of negative emotionality

White noise speech illusion and psychosis expression:An experimental investigation of psychosis liability

Background: An association between white noise speech illusion and psychotic symptoms has been reported in patients and their relatives. This supports the theory that bottom-up and top-down perceptual processes are involved in the mechanisms underlying perceptual abnormalities. However, findings in nonclinical populations have been conflicting. Objectives: The aim of this study was to examine the association between white noise speech illusion and subclinical expression of psychotic symptoms in a nonclinical sample. Findings were compared to previous results to investigate potential methodology dependent differences. Methods: In a general population adolescent and young adult twin sample (n = 704), the association between white noise speech illusion and subclinical psychotic experiences, using the Structured Interview for Schizotypy-Revised (SIS-R) and the Community Assessment of Psychic Experiences (CAPE), was analyzed using multilevel logistic regression analyses. Results: Perception of any white noise speech illusion was not associated with either positive or negative schizotypy in the general population twin sample, using the method by Galdos et al. (2011) (positive: ORadjusted: 0.82, 95% CI: 0.6-1.12, p = 0.217; negative: ORadjusted: 0.75, 95% CI: 0.56-1.02, p = 0.065) and the method by Catalan et al. (2014) (positive: ORadjusted: 1.11, 95% CI: 0.79-1.57, p = 0.557). No association was found between CAPE scores and speech illusion (ORadjusted: 1.25, 95% CI: 0.88-1.79, p = 0.220). For the Catalan et al. (2014) but not the Galdos et al. (2011) method, a negative association was apparent between positive schizotypy and speech illusion with positive or negative affective valence (ORadjusted: 0.44, 95% CI: 0.24-0.81, p = 0.008). Conclusion: Contrary to findings in clinical populations, white noise speech illusion may not be associated with psychosis proneness in nonclinical populations

The reliability of the Structured Interview for Schizotypy-Revised

We investigated the reliability of the Structured Interview for Schizotypy-Revised (SIS-R). The original interview (SIS) was developed by Kendler, We revised the SIS, primarily by standardizing the rating procedures. Operational definitions and explicit criteria for rating were given. We introduced a four-point scale and provided clear criteria for rating severity of symptoms and signs (frequency, duration, and level of conviction) to operationalize schizotypal features, We divided schizotypal signs of global affect and global organization of speech into three separate signs of affect and five separate signs of thinking and speech. The main goal of this study was the assessment of test-retest reliability of the SIS-R, A robust test-retest design using different interviewers at both times, with a mean interval of 19 days, was used. The sample consisted of 42 psychiatric patients, almost all with personality disorders. The strong linear-weighted kappa statistic was used to evaluate reliability. The first conclusion is that most schizotypal symptoms can be reliably assessed with the SIS-R, The second conclusion Is that most schizotypal signs do not reach sufficient levels of reliability, After unreliable items are excluded, the shortened SIS-R is a reliable research instrument for measuring schizotypal features (as far as it concerns our mixed samples). It covers all three dimensions of schizotypy

THE MULTIDIMENSIONALITY OF SCHIZOTYPY

We present an overview of self-report scales for measuring schizotypy and a review of factor-analytical studies of these scales. These studies show that schizotypy is a multidimensional construct consisting of three or four factors. Positive Schizotypy, Negative Schizotypy, Nonconformity, and possibly Social Anxiety/Cognitive Disorganization. Clinical and external validation studies provide support for the construct validity of the Positive Schizotypy and Negative Schizotypy factors, but as yet fail to support the Nonconformity and Social Anxiety/Cognitive Disorganization factors. In accordance with this multidimensional structure, the stales for measuring schizotypy can be classified as factor-specific scales. We consider the striking similarities between the multidimensionality of schizotypal traits and the multidimensionality of schizophrenic symptoms. We also look at the similarities and differences between schizotypy and normal personality traits. Some practical and theoretical implications of these relationships are discussed