Testing the psychosis continuum: differential impact of genetic and nongenetic risk factors and comorbid psychopathology across the entire spectrum of psychosis

Genetic Susceptibility to the Environment Moderates the Impact of Childhood Experiences on Psychotic, Depressive, and Anxiety Dimensions

BACKGROUND AND HYPOTHESIS

Gene-by-environment (GxE) studies in psychosis have exclusively focused on negative exposures. However, evidence supports the resilience-enhancing effect of positive factors on psychosis outcome. The Differential Susceptibility (DS) model proposes that common genetic variants may confer not only disproportionate responsiveness to negative environments, but also greater sensitivity to positive, resilience-enhancing conditions. This study is the first to apply the DS model to the expression of subclinical psychosis, employing polygenic risk scores of environmental sensitivity (PRS-ES). PRS-ES were hypothesized to moderate, in a DS manner, associations between childhood adversity and psychosis, affective, and anxiety dimensions in young adults. An exploratory goal examined whether PRS for psychotic-like experiences (PRS-PLE) also showed DS patterns.

STUDY DESIGN

PRS, schizotypy, PLE, depression, anxiety, and childhood adversity ratings were obtained for 197 nonclinical young adults. LEGIT software for testing competitive-confirmatory GxE models was employed.

STUDY RESULTS

Results largely supported DS: Individuals high on PRS-ES showed increased subclinical psychosis, depression, and anxiety if they had experienced elevated childhood adversity, and lower symptoms if exposed to low levels of adversity as compared with those with low PRS-ES. Similarly, PRS-PLE moderated the effect of adversity on PLE, positive schizotypy, and depression following the DS model, but only PRS-ES moderation on PLE survived statistical correction.

CONCLUSIONS

Our results suggest that genetic DS to the environment is relevant to psychosis, depression, and anxiety. Current debates on reconceptualization of genetic "risk" and resilience may benefit from this insight that support optimistic views on preventative efforts for early detection and intervention.

Genetic Differences in Reactivity to the Environment Impact Psychotic-Like and Affective Reactivity in Daily Life

BACKGROUND AND HYPOTHESIS

Consistent with diathesis-stress models, psychosis research has focused on genetic moderation of adverse environmental exposures. In contrast, the Differential Susceptibility (DS) model suggests that the same genetic variants that increase risk-inducing effects of adverse experiences also enhance beneficial effects from positive experiences. This study examined whether individuals with high genetic susceptibility to the environment showed differential psychotic-like and affective reactivity in response to positive and negative events in daily life.

STUDY DESIGN

Experience sampling methodology assessed context (positive and stressful) and momentary levels of paranoia, psychotic-like experiences (PLE), and positive (PA) and negative affect (NA) in 217 non-clinical adults oversampled for schizotypy. Linear mixed models examined whether Polygenic Risk Scores of Environmental Sensitivity (PRS-ES) moderated the impact of current context on subsequent experiences.

STUDY RESULTS

PRS-ES moderated positive, but not stressful, context on subsequent levels of momentary paranoia, NA, and PA, but not PLE. Genetic and environmental (G × E) interactions indicated diathesis-stress at lower thresholds of PRS-ES, but a DS model at the highest threshold of the PRS-ES. Participants with elevated PRS-ES showed increased paranoia and NA and decreased PA in subsequent assessments when reporting low levels of positive situations, but also decreased paranoia and NA and increased PA when rating contexts as positive.

CONCLUSIONS

Findings support the influence of genetic sensitivity to the environment on psychotic-like and affective reactivity in daily life, particularly in response to positive contexts. This highlights the transdiagnostic protective role of positive experiences and informs ecological momentary interventions.

Beyond the Descriptive: A Comprehensive, Multidomain Validation of Symptom Trajectories for Individuals at Clinical High Risk for Psychosis

BACKGROUND

Although the clinical high risk for psychosis (CHR-P) criteria are widely used to ascertain individuals at heightened risk for imminent onset of psychosis, it remains controversial whether CHR-P status defines a diagnostic construct in its own right. In a previous study, CHR-P nonconverters were observed to follow 3 distinct trajectories in symptoms and functioning: remission, partial remission, and maintenance of symptoms and functional impairments at subthreshold levels of intensity.

METHODS

Here, we utilized the NAPLS3 (North American Prodrome Longitudinal Study phase 3) sample (N = 806) to determine whether 1) the same trajectory groups can be detected when assessing symptoms at 2-month intervals over an 8-month period and 2) the resulting trajectory groups differ from each other and from healthy control participants and converting CHR-P cases in terms of risk factors, comorbidities, and functional outcomes.

RESULTS

Three distinctive subgroups within the CHR nonconverters were identified, largely paralleling those observed previously. Importantly, these extracted groups, together with non-CHR control participants and CHR converters, differed from each other significantly on putative etiological risk factors (e.g., predicted risk scores, physiological and self-report measures of stress), affective comorbidities, and functional outcomes, thus providing converging evidence supporting the validity of the identified trajectory groups.

CONCLUSIONS

This pattern, together with the fact that even the subgroup of CHR-P nonconverters who showed a remission trajectory deviated from healthy control participants, supports treating the CHR-P syndrome not only as a status that denotes risk for onset of full psychosis but also as a marker of ongoing distress for a population that is in need of interventions.

The impact of affective and negative symptoms on the development of psychosis in a six-year follow-up of a community-based population

PURPOSE

The Clinical High Risk (CHR) concept has a limited transition risk to psychotic disorders (PD). This study investigates the association between affective and negative symptoms, currently not included in the CHR concept, and the risk of transition to PD in a community-based population of 2185 participants in Turkey.

METHODS

Participants were assessed twice over six years using a multistage sampling technique. Two separate linear regression analyses were conducted on data from both assessments, investigating the relationship between affective and negative symptoms, subclinical and clinical psychotic experiences (PE) and progression to PD.

RESULTS

The overall transition rate to PD was 1.3%. The analysis showed no increased risk of developing PD for the 'subclinical PE only' group at follow-up, compared to the 'no PE' group. However, being classified as having 'clinical PE only' (OR: 6.23; p = 0.010) and 'clinical PE + affective/negative symptoms' (OR: 8.48; p = 0.001) at baseline was associated with an increased risk of developing PD at follow-up. The presence of 'affective/negative symptoms' at baseline was associated with an increased risk of incident subclinical PE (RR: 1.98; p = 0.001), incident clinical PE (RR: 3.14; p = 0.001), and incident PD (RR: 4.21; p = 0.030) at follow-up.

CONCLUSION

The results confirm the significance of the baseline severity of positive symptoms in predicting the transition to PD and suggest that both positive and affective/negative symptoms impact the transition risk to PD and incident psychotic symptoms. This highlights the potential utility of defining CHR groups based on a combination of positive, affective, and negative symptoms.

Defining Urbanicity in the Context of Psychosis Research: A Qualitative Systematic Literature Review

BACKGROUND AND HYPOTHESIS

Numerous studies have found that being born or raised in urban environments increases the odds of developing psychosis in Northern and Western Europe. However, available research from Southern Europe, Latin America, and Asia has reported null results. A limitation in most studies to date is the inadequate characterization of urban and rural life components that may contribute to varying psychosis risk across regions.

STUDY DESIGN

To deepen our understanding of the different concepts and measures of urbanicity and related factors in psychosis research, we conducted a qualitative systematic literature review extracting information from studies published between 2000 and 2024.

STUDY RESULTS

Sixty-one articles met the inclusion and exclusion criteria and were used in the thematic analysis. The analysis revealed that urbanicity lacked a single, coherent definition across studies and regions. Three major categories of themes were developed from the analysis: (1) Urbanicity comprises several interconnected constructs, (2) Urbanicity measurements vary between countries from the Global North and the Global South, and (3) Urbanicity operates through key neighborhood-level mechanisms.

CONCLUSIONS

Future research on urbanicity and psychosis should consider the potential limitations of urbanicity's conceptualization and operationalization and aim to address these limitations by focusing on contextual, historical, and community-level factors, utilizing locally validated measures, and employing mixed-method designs.

Characteristics and factors associated with psychotic-like experiences in remission: a cross-sectional study of 4208 college students in China

OBJECTIVES

Previous research has extensively explored the factors associated with psychotic-like experiences (PLEs). However, the characteristics and associated factors of remitted PLEs, which refer to the absence of current PLEs following previous PLEs, remain unclear. Therefore, this study aims to describe the characteristics of adolescents who reported remitted PLEs.

DESIGN

Cross-sectional study.

SETTING

The survey was conducted from October to December 2020 in three colleges located in Guangzhou, China.

PARTICIPANTS

A total of 4208 college freshmen aged from 15 to 24 participated in our survey.

PRIMARY AND SECONDARY OUTCOME MEASURES

The 15-item positive subscale of the Community Assessment of the Psychic Experience was used to assess both lifetime and current PLEs. Multivariate logistic regression models were used to examine the associations between remitted PLEs and a range of demographic factors, lifestyle, psychosocial factors, lifetime affective symptoms and sleep problems.

RESULTS

Three groups of PLEs were observed: non-PLEs (47.27% of the sample), remitted PLEs (40.42%) and current PLEs (12.31%). Several factors have been identified as shared correlates of remission and absence of PLEs, including fewer recent adverse life events, greater resilience, fewer symptoms of depression and anxiety, and early waking. Furthermore, higher levels of social support (OR 1.48, 95% CI 1.01 to 2.17; OR 1.53, 95% CI 1.18 to 1.97) was a specific factor associated with the remission of PLEs. Compared with individuals without PLEs, those with remitted PLEs were more likely to be female (OR 1.50, 95% CI 1.28 to 1.75), less likely to be younger (OR 0.88, 95% CI 0.81 to 0.95) and prone to have more chronic physical illness (OR 1.67, 95% CI 1.29 to 2.16), habitual alcohol intake (OR 1.85, 95% CI 1.19 to 2.88), more childhood trauma (OR for low vs high=0.72, 95% CI 0.57 to 0.91) and the sleep problems of waking up easily (OR 1.36, 95% CI 1.12 to 1.65).

CONCLUSION

These findings suggest that remitted PLEs play a vital, unique role among three groups and provide preliminary targets for the intervention for adolescents at risk of mental health problems. Further investigation may shed light on the causality of the relationship between remitted PLEs and associated factors.

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.

Changes in responses of the amygdala and hippocampus during fear conditioning are associated with persecutory beliefs

The persecutory delusion is the most common symptom of psychosis, yet its underlying neurobiological mechanisms are poorly understood. Prior studies have suggested that abnormalities in medial temporal lobe-dependent associative learning may contribute to this symptom. In the current study, this hypothesis was tested in a non-clinical sample of young adults without histories of psychiatric treatment (n = 64), who underwent classical Pavlovian fear conditioning while fMRI data were collected. During the fear conditioning procedure, participants viewed images of faces which were paired (the CS+) or not paired (the CS-) with an aversive stimulus (a mild electrical shock). Fear conditioning-related neural responses were measured in two medial temporal lobe regions, the amygdala and hippocampus, and in other closely connected brain regions of the salience and default networks. The participants without persecutory beliefs (n = 43) showed greater responses to the CS- compared to the CS+ in the right amygdala and hippocampus, while the participants with persecutory beliefs (n = 21) failed to exhibit this response. These between-group differences were not accounted for by symptoms of depression, anxiety or a psychosis risk syndrome. However, the severity of subclinical psychotic symptoms overall was correlated with the level of this aberrant response in the amygdala (p = .013) and hippocampus (p = .033). Thus, these findings provide evidence for a disruption of medial temporal lobe-dependent associative learning in young people with subclinical psychotic symptoms, specifically persecutory thinking.

Psychosis superspectrum I: Nosology, etiology, and lifespan development

This review describes the Hierarchical Taxonomy of Psychopathology (HiTOP) model of psychosis-related psychopathology, the psychosis superspectrum. The HiTOP psychosis superspectrum was developed to address shortcomings of traditional diagnoses for psychotic disorders and related conditions including low reliability, arbitrary boundaries between psychopathology and normality, high symptom co-occurrence, and heterogeneity within diagnostic categories. The psychosis superspectrum is a transdiagnostic dimensional model comprising two spectra-psychoticism and detachment-which are in turn broken down into fourteen narrow components, and two auxiliary domains-cognition and functional impairment. The structure of the spectra and their components are shown to parallel the genetic structure of psychosis and related traits. Psychoticism and detachment have distinct patterns of association with urbanicity, migrant and ethnic minority status, childhood adversity, and cannabis use. The superspectrum also provides a useful model for describing the emergence and course of psychosis, as components of the superspectrum are relatively stable over time. Changes in psychoticism predict the onset of psychosis-related psychopathology, whereas changes in detachment and cognition define later course. Implications of the superspectrum for genetic, socio-environmental, and longitudinal research are discussed. A companion review focuses on neurobiology, treatment response, and clinical utility of the superspectrum, and future research directions.

Emotion regulation flexibility and psychosis: A longitudinal study disentangling components of flexibility in psychosis-proneness

OBJECTIVES

Flexibility in self-regulation has emerged as an important component of mental health. Previous findings found that deficits in two components of regulatory flexibility were linked cross-sectionally to psychosis-proneness. We aimed to replicate and extend these findings longitudinally.

METHODS

We measured psychosis-proneness and components of emotion regulation flexibility (i.e. context sensitivity, repertoire and feedback) at two time points with three months in between.

RESULTS

Two flexibility components predicted psychotic-like experiences. The ability to detect the absence of contextual cues was implicated in both positive and negative dimensions but through opposite pathways. Expressive suppression ability-a subcomponent of repertoire-predicted positive symptoms. None of the flexibility components predicted distress related to the symptoms.

CONCLUSIONS

The current study provides further evidence on the implication of emotion regulation flexibility in the longer-term maintenance of psychotic-like experiences. Future studies can advance this work further by evaluating possible bidirectional relationships between psychotic-like experiences and deficits in emotion regulation flexibility.

The association of social inequality with the onset, persistence, and progression of psychotic experiences along the extended psychosis phenotype: a 6-year follow-up study in a community-based sample

PURPOSE

This paper aims to investigate associations between early childhood and current indicators of socioeconomic inequality and the onset (incident), persistence and progression (increase in severity) of psychotic experiences (PEs) in a longitudinal follow-up of a community-based population.

METHODS

Households in the metropolitan area of Izmir, Turkey were contacted in a multistage clustered probability sampling frame, at baseline (T1, n = 4011) and at 6-year follow-up (T2, n = 2185). Both at baseline and follow-up, PEs were assessed using Composite International Diagnostic Interview 2.1. The associations between baseline socioeconomic features and follow-up PEs were analysed using logistic regression models. Indicators of social inequality included income, educational level, current socioeconomic status (SES), social insurance, the area resided, ethnicity, parental educational level, and SES at birth.

RESULTS

The risk of onset of PEs was significantly higher in lower education, lower SES, and slum-semi-urban areas. The persistence of PEs was significantly associated with the lowest levels of education and current SES, and rural residency. Persistent PEs were significantly and negatively associated with paternal SES at birth. Progression of PEs was significantly higher among respondents with educational achievements lower than university level and lower levels of SES, who have no social insurance and who reside in slum-semi-urban areas. Parental education and paternal SES at birth were not associated with the persistence of PEs.

CONCLUSION

Indicators of social inequality (low education, low SES, low income, and poverty in the neighbourhood) were associated with the onset and persistence of PEs and progression along the extended psychosis phenotype. The early indicators seem to have a modest life-long impact on the psychosis phenotype.

The Role of Cannabis in the Development of Psychosis

Cannabis is known to cause psychotic disorders, and the increasing use of cannabis constitutes an important health problem. Growing evidence that cannabis causes the development of psychosis has led to an increase in the number of studies in this field. This review aims to clarify the role of cannabis use in the development of psychosis, discuss the current literature about the underlying neurobiological mechanisms. For this purpose PubMed was searched for the keywords "cannabis use, psychosis, schizophrenia, endocannabinoid system, pathophysiology, neurobiology"; the articles published in the last 10 years were reviewed. Epidemiological studies showed that cannabis use starting at an earlier age is associated with an increased risk of psychosis, this risk is more pronounced in people with genetic predisposition and increases with heavy and high potency cannabis use. Studies showed that the endocannabinoid system, which plays a role in nervous system development and functions as a homeostatic regulator in physiological processes, is affected by cannabis use during critical periods of development like adolescence; cannabis use affects physiological processes such as synaptic pruning due to the effects of this system on neurotransmitters like glutamate and dopamine leading to long-term behavioral and psychological consequences. Additionally, evidence that dysfunctions in the endocannabinoid system play a role in the etiology of schizophrenia suggests that cannabis affects the disease process by worsening existing dysfunctions in this system. Understanding the relationship between cannabis use and the development of psychosis and underlying neurobiological mechanisms will help to identify new treatment targets, and develop appropriate preventive approaches. Keywords: Cannabis Abuse, Psychotic Disorders, Schizophrenia, Endocannabinoids, Neurobiology.

Urbanicity and psychotic disorders: Facts and hypotheses

In the present qualitative literature review, we summarise data on psychotic disorders and urbanicity, focusing particularly on recent findings. Longitudinal studies of the impact of urbanicity on the risk for psychotic disorders have consistently shown a significant association, with a relative risk between 2 and 2.5. However, most of the original studies were conducted in Western Europe, and no incidence studies were conducted in low- and middle-income countries. European studies suggest that neighbourhood-level social fragmentation and social capital may partly explain this association. Exposure to air pollution (positive association) and green space (negative association) may also be part of the explanation, but to date, available data do not make it possible to conclude if they act independently from urbanicity, or as part of the effect of urbanicity on psychotic disorders. Finally, several studies have consistently shown significant associations between the polygenic risk score for schizophrenia and urbanicity, with several possible explanations (pleiotropic effects, results of prodromic symptoms, or selection/intergenerational hypothesis). Thus, more studies are needed to understand the factors that explain the association between urbanicity and the risk of psychotic disorders. Further studies should account for the interdependence and/or interactions of different psychosocial and physical exposures (as well as gene-environment interactions), and explore this association in low- and middle-income countries.

Measurement invariance across age, gender, ethnicity, and psychopathology of the Psychotic-Like Experiences Questionnaire for Children in a community sample

OBJECTIVES

The current study aimed to assess the measurement invariance of the 9-item self-report Psychotic-Like Experiences Questionnaire for Children (PLEQ-C) across various demographic (age, gender, ethnicity) and psychopathology profiles in a community sample of children.

METHODS

Children aged 9-11 years (n = 613; M age = 10.4 years [SD = 0.8]; 50.9% female) completed questionnaire screening at school, with primary caregivers returning questionnaires by mail from home. Configural, metric, scalar, and residual invariance of the PLEQ-C scores were investigated across groups differentiated by age (9; 10; 11 years), gender (female; male), ethnicity (white; black; other), and by child-reported and caregiver-reported psychopathology (abnormal rating; not abnormal).

RESULTS

The PLEQ-C scores demonstrated good unidimensional model fit. Full configural, metric, scalar, and residual invariance were demonstrated across gender, ethnicity, and psychopathology (both child- and caregiver-reported). Across age groups, the PLEQ-C scores showed full configural and metric invariance, but only partial scalar and residual invariance (with a single item measuring differently among 11-year-olds).

CONCLUSIONS

In this community sample, the PLEQ-C was robust to age, gender, ethnicity, and psychopathology profiles, providing evidence of its capacity to identify children in the general population who might benefit from further assessment to determine the clinical significance of their psychotic experiences.

Conceptualizing a less paranoid schizophrenia

Schizophrenia stands as one of the most studied and storied disorders in the history of clinical psychology; however, it remains a nexus of conflicting and competing conceptualizations. Patients endure great stigma, poor treatment outcomes, and condemnatory prognosis. Current conceptualizations suffer from unstable categorical borders, heterogeneity in presentation, outcome and etiology, and holes in etiological models. Taken in aggregate, research and clinical experience indicate that the class of psychopathologies oriented toward schizophrenia are best understood as spectra of phenomenological, cognitive, and behavioral modalities. These apparently taxonomic expressions are rooted in normal human personality traits as described in both psychodynamic and Five Factor personality models, and more accurately represent explicable distress reactions to biopsychosocial stress and trauma. Current categorical approaches are internally hampered by axiomatic bias and systemic inertia rooted in the foundational history of psychological inquiry; however, when such axioms are schematically decentralized, convergent cross-disciplinary evidence outlines a more robust explanatory construct. By reconceptualizing these disorders under a dimensional and cybernetic model, the aforementioned issues of instability and inaccuracy may be resolved, while simultaneously opening avenues for both early detection and intervention, as well as for more targeted and effective treatment approaches.

Cross-sectional association between metabolic parameters and psychotic-like experiences in a population-based sample of middle-aged and elderly individuals

BACKGROUND

Metabolic alterations are often found in patients with clinical psychosis early in the course of the disorder. Psychotic-like experiences are observed in the general population, but it is unclear whether these are associated with markers of metabolism.

METHODS

A population-based cohort of 1890 individuals (mean age 58.0 years; 56.3% women) was included. Metabolic parameters were measured by body-mass index (BMI), concentrations of low-density and high-density lipoprotein cholesterol (LDL-C and HDL-C), total cholesterol, triglycerides, and fasting glucose and insulin in blood. Frequency and distress ratings of psychotic-like experiences from the positive symptom dimension of the Community Assessment of Psychic Experience questionnaire were assessed. Cross-sectional associations were analysed using linear regression analyses.

RESULTS

Higher BMI was associated with higher frequency of psychotic-like experiences (adjusted mean difference: 0.04, 95% CI 0.02-0.06) and more distress (adjusted mean difference: 0.02, 95% CI 0.01-0.03). Lower LDL-C was associated with more psychotic-like experiences (adjusted mean difference: -0.23, 95% CI -0.40 to -0.06). When restricting the sample to those not using lipid-lowering medication, the results of BMI and LDL-C remained and an association between lower HDL-C and higher frequency of psychotic-like experiences was found (adjusted mean difference: -0.37, 95% CI -0.69 to -0.05). We observed no significant associations between cholesterol, triglycerides, glucose, insulin or homeostatic model assessment and psychotic-like experiences.

CONCLUSIONS

In a population-based sample of middle-aged and elderly individuals, higher BMI and lower LDL-C were associated with psychotic-like experiences. This suggests that metabolic markers are associated with psychotic-like experiences across the vulnerability spectrum.

A 6-year follow-up study in a community-based population: Is neighbourhood-level social capital associated with the risk of emergence and persistence of psychotic experiences and transition to psychotic disorder?

BACKGROUND

Social capital is thought to represent an environmental factor associated with the risk of psychotic disorder (PD). This study aims to investigate the association between neighbourhood-level social capital and clinical transitions within the spectrum of psychosis.

METHODS

In total, 2175 participants, representative of a community-based population, were assessed twice (6 years apart) to determine their position within an extended psychosis spectrum: no symptoms, subclinical psychotic experiences (PE), clinical PE, PD. A variable representing change between baseline (T1) and follow-up (T2) assessment was constructed. Four dimensions of social capital (informal social control, social disorganisation, social cohesion and trust, cognitive social capital) were assessed at baseline in an independent sample, and the measures were aggregated to the neighbourhood level. Associations between the variable representing psychosis spectrum change from T1 to T2 and the social capital variables were investigated.

RESULTS

Lower levels of neighbourhood-level social disorganisation, meaning higher levels of social capital, reduced the risk of clinical PE onset (OR 0.300; z = -2.75; p = 0.006), persistence of clinical PE (OR 0.314; z = -2.36; p = 0.018) and also the transition to PD (OR 0.136; z = -2.12; p = 0.034). The other social capital variables were not associated with changes from T1 to T2.

CONCLUSIONS

Neighbourhood-level social disorganisation may be associated with the risk of psychosis expression. Whilst replication of this finding is required, it may point to level of social disorganisation as a public health target moderating population psychosis risk.

Disentangling heterogeneity of psychosis expression in the general population: sex-specific moderation effects of environmental risk factors on symptom networks

BACKGROUND

Psychosis expression in the general population may reflect a behavioral manifestation of the risk for psychotic disorder. It can be conceptualized as an interconnected system of psychotic and affective experiences; a so-called 'symptom network'. Differences in demographics, as well as exposure to adversities and risk factors, may produce substantial heterogeneity in symptom networks, highlighting potential etiological divergence in psychosis risk.

METHODS

To explore this idea in a data-driven way, we employed a novel recursive partitioning approach in the 2007 English National Survey of Psychiatric Morbidity (N = 7242). We sought to identify 'network phenotypes' by explaining heterogeneity in symptom networks through potential moderators, including age, sex, ethnicity, deprivation, childhood abuse, separation from parents, bullying, domestic violence, cannabis use, and alcohol.

RESULTS

Sex was the primary source of heterogeneity in symptom networks. Additional heterogeneity was explained by interpersonal trauma (childhood abuse and domestic violence) in women and domestic violence, cannabis use, ethnicity in men. Among women, especially those exposed to early interpersonal trauma, an affective loading within psychosis may have distinct relevance. Men, particularly those from minority ethnic groups, demonstrated a strong network connection between hallucinatory experiences and persecutory ideation.

CONCLUSION

Symptom networks of psychosis expression in the general population are highly heterogeneous. The structure of symptom networks seems to reflect distinct sex-related adversities, etiologies, and mechanisms of symptom-expression. Disentangling the complex interplay of sex, minority ethnic group status, and other risk factors may help optimize early intervention and prevention strategies in psychosis.

Prevalence, service use and clinical correlates of hallucinations and delusions in an out-patient population from India

BACKGROUND

Despite the persistent public health problem of positive psychotic symptoms, understanding of symptom specific prevalence rates, clinical correlates and service utilisation are sparse.

AIMS

The current study aimed to establish prevalence, clinical and service utilisation correlates of hallucinations and delusions in people accessing outpatient clinics in Tamil Nadu, India.

METHODS

Secondary patient data from outpatient clinics, over a 12-month period, in 2016, was used for analysis (N = 917). Based on the presence of positive psychotic symptoms (PPSx), the sample was divided into four groups for analysis- hallucinations-only (H), delusions-only (D), both hallucinations and delusions (HD) and neither PPSx (N-PPSx).

RESULTS

Findings indicate that the most prevalent PPSx were hallucinations (10.7%) however, barriers to service utilisation and clinical correlates were associated predominantly with the D and the HD group; as was severe work impairment. Yet, this group was most likely to remain with psychiatric services. Lastly, diagnostic challenges were apparent within the sample.

CONCLUSIONS

The study revealed that despite more barriers to service utilisation, persons with PPSx remain in contact with services. Yet prognosis remains only moderate at best, indicating other mediating and underlying factors impeding recovery may be interplaying and, therefore, a need for enhanced biopsychosocial approaches.

Meta-analysis of structural evidence for the Hierarchical Taxonomy of Psychopathology (HiTOP) model

BACKGROUND

The Hierarchical Taxonomy of Psychopathology (HiTOP) is a classification system that seeks to organize psychopathology using quantitative evidence - yet the current model was established by narrative review. This meta-analysis provides a quantitative synthesis of literature on transdiagnostic dimensions of psychopathology to evaluate the validity of the HiTOP framework.

METHODS

Published studies estimating factor-analytic models from diagnostic and statistical manual of mental disorders (DSM) diagnoses were screened. A total of 120,596 participants from 35 studies assessing 23 DSM diagnoses were included in the meta-analytic models. Data were pooled into a meta-analytic correlation matrix using a random effects model. Exploratory factor analyses were conducted using the pooled correlation matrix. A hierarchical structure was estimated by extracting one to five factors representing levels of the HiTOP framework, then calculating congruence coefficients between factors at sequential levels.

RESULTS

Five transdiagnostic dimensions fit the DSM diagnoses well (comparative fit index = 0.92, root mean square error of approximation = 0.07, and standardized root-mean-square residual = 0.03). Most diagnoses had factor loadings >|0.30| on the expected factors, and congruence coefficients between factors indicated a hierarchical structure consistent with the HiTOP framework.

CONCLUSIONS

A model closely resembling the HiTOP framework fit the data well and placement of DSM diagnoses within transdiagnostic dimensions were largely confirmed, supporting it as valid structure for conceptualizing and organizing psychopathology. Results also suggest transdiagnostic research should (1) use traits, narrow symptoms, and dimensional measures of psychopathology instead of DSM diagnoses, (2) assess a broader array of constructs, and (3) increase focus on understudied pathologies.

Investigating predictors contributing to the expression of schizotypy during the COVID-19 pandemic

The coronavirus (COVID-19) pandemic has caused major disruptions to social and other forms of functioning, which may influence schizotypy expression. The current study aimed to explore possible distal and proximal predictors contributing to schizotypy in a sample of the Australian general population during the COVID-19 pandemic. The COvid-19 and you: mentaL heaLth in AusTralia now survEy (COLLATE) project is an online mental health study aimed at tracking key mental health indicators over the progression of the pandemic. Adults residing in Australia were invited to take part using non-discriminative snowball sampling. Demographic-clinical information was collected for 850 participants in either October 2020 or January 2021. To assess schizotypy facets, the Launay-Slade Hallucinations Scale-Extended (LSHS-E) and Peters Delusions Inventory (PDI-21) were used to measure hallucination and delusion proneness respectively. Generalised linear models (with gamma and negative binomial distributions) were employed. Age, negative emotions and loneliness significantly contributed to both hallucination and delusion proneness; gender, education and religiosity also significantly contributed to delusion proneness, in the final regression models. Our study corroborated the specific contribution of loneliness, amongst other factors, in the prediction of schizotypy facets. Tackling loneliness represents a public health challenge that needs to be urgently addressed, especially in the face of the ongoing COVID-19 pandemic.

Pathways linking school bullying and psychotic experiences: Multiple mediation analysis in Chinese adolescents and young adults

It is found that people with psychotic experiences have a 4-fold increased risk of developing a psychotic disorder later in life. Indeed, accumulating evidence has suggested that the association between school bullying and psychotic experiences works linearly. Previous studies are mainly carried out in a Western context, and only seldomly do studies address whether the association exists in the Chinese population and the related psychological and cognitive mechanisms. Therefore, we carried out the current study to address this gap in the literature focusing on the lifelong school bullying experiences of Chinese adolescents and young adults. We examined them in relation to psychotic experiences while assessing the mediating role of self-esteem, the personality trait of neuroticism, and a cognitive bias in thinking called interpretation bias. We found that multiple victimizations were quite common in Hong Kong secondary schools. In addition to a significant association between school bullying and psychotic experiences, we found partial mediating effects of proposed psychological and cognitive mediators in constructed multiple mediation models utilizing bootstrapping approach. Specifically, bullying quantity reflecting the number of victimizations, had its association with psychotic experiences partially mediated by the personality trait of neuroticism. In contrast, bullying duration reflecting the lasting of victimization was associated with psychotic experiences partially mediated by the personality trait of neuroticism and interpretation bias. Our findings enhance our knowledge of mechanisms underpinning the psychosis spectrum development and have implications for school-based intervention programs targeting bullying victims.

Testing extra-linearity across a psychosis continuum

BACKGROUND

It is unclear whether psychotic experiences (PEs) gradually merge into states of clinical psychosis along a continuum which correspond to a dimensional classification or whether latent classes appear above a certain severity threshold which correspond better to diagnostic categories of psychosis.

METHODS

Annual cross-sectional surveys, 2014-19, among Chinese undergraduates (N = 47,004) measured PEs, depression and etiological risk factors using standardized self-report instruments. We created a psychosis continuum with five levels and tested linear and extra-linear contrasts in associated etiological risk factors, before and after adjustment for depression. We carried out latent class analysis.

RESULTS

Categorical expression of psychosis, including hallucinations and delusions, nuclear symptoms, and nuclear symptoms and depression were found at severe level 5. Etiological risk factors which impacted linearly across the continuum were more common for depression. Child maltreatment impacted extra-linearly on both psychosis and depression. Family history of psychosis impacted linearly on psychosis; male sex and urban birth impacted extra-linearly and were specific for psychosis. Four latent classes were found, but only at level 5. These corresponded to nuclear schizophrenia symptoms, nuclear schizophrenia and depressive symptoms, severe depression, and an unclassified category with moderate prevalence of PEs.

CONCLUSION

Quantitative and qualitative changes in the underlying structure of psychosis were observed at the most severe level along a psychosis continuum, where four latent classes emerged. These corresponded to existing categorical classifications but require confirmation with clinical interview. PEs are non-specific and our findings suggest some are on a continuum with depression, whilst others are on a continuum with non-affective psychosis. Differing patterns of impact from etiological risk factors across the spectrum of psychopathology determine outcome at the most severe level of these continua.

Schizophrenia: a classic battle ground of nature versus nurture debate

Much has been learned about the etiology and pathogenesis of schizophrenia since the term was first used by Eugene Bleuler over a century ago to describe one of the most important forms of major mental illness to affect mankind. Both nature and nurture feature prominently in our understanding of the genesis of the overall risk of developing schizophrenia. We now have a firm grasp of the broad structure of the genetic architecture and several key environmental risk factors have been identified and delineated. However, much of the heritability of schizophrenia remains unexplained and the reported environmental risk factors do not explain all the variances not attributable to genetic risk factors. The biggest problem at present is that our understanding of the causal mechanisms involved is still in its infancy. In this review, we describe the extent and limits of our knowledge of the specific genetic/constitutional and non-genetic/environmental factors that contribute to the overall risk of schizophrenia. We suggest novel methods may be required to understand the almost certainly immensely complex multi-level causal mechanisms that contribute to the generation of the schizophrenia phenotype.

The Independent Effects of Psychosocial Stressors on Subclinical Psychosis: Findings From the Multinational EU-GEI Study

The influence of psychosocial stressors on psychosis risk has usually been studied in isolation and after the onset of the disorder, potentially ignoring important confounding relationships or the fact that some stressors that may be the consequence of the disorder rather than preexisting. The study of subclinical psychosis could help to address some of these issues. In this study, we investigated whether there was (i) an association between dimensions of subclinical psychosis and several psychosocial stressors including: childhood trauma, self-reported discrimination experiences, low social capital, and stressful life experiences, and (ii) any evidence of environment-environment (ExE) interactions between these factors. Data were drawn from the EUGEI study, in which healthy controls (N = 1497) and siblings of subjects with a psychotic disorder (N = 265) were included in six countries. The association between psychosocial stressors and subclinical psychosis dimensions (positive, negative and depressive dimension as measured by the Community Assessment of Psychic Experiences (CAPE) scale) and possible ExE interactions were assessed using linear regression models. After adjusting for sex, age, ethnicity, country, and control/sibling status, childhood trauma (β for positive dimension: 0.13, negative: 0.49, depressive: 0.26) and stressful life events (positive: 0.08, negative: 0.16, depressive: 0.17) were associated with the three dimensions. Lower social capital was associated with the negative and depression dimensions (negative: 0.26, depressive: 0.13), and self-reported discrimination experiences with the positive dimension (0.06). Our findings are in favor of independent, cumulative and non-specific influences of social adversities in subclinical psychosis in non-clinical populations, without arguments for E × E interactions.

Psychotic experiences in seven-year-old children with familial high risk of schizophrenia or bipolar disorder in: The Danish High Risk and Resilience Study - VIA 7; A population-based cohort study

We aimed to examine the prevalence of psychotic experiences (PEs) in children with familial high risk of schizophrenia (FHR-SZ) or bipolar disorder (FHR-BP) and, in exploratory analyses, to examine the possible associations between PEs and mental disorders as well as level of functioning. A cohort of seven-year-old children with FHR-SZ (N = 199), FHR-BP (N = 118) and controls (N = 196) was recruited through Danish nationwide registers. Lifetime PEs were assessed through interviews using the psychosis section of the 'Schedule for Affective Disorders and Schizophrenia for School-Age Children - Present and Lifetime Version' (K-SADS-PL). Lifetime DSM-IV diagnoses were ascertained through K-SADS-PL and the level of functioning of the children through 'Children's Global Assessment Scale'. Both children with FHR-SZ (OR = 2.9, 95% CI = 1.4-6.2, p = 0.005) and FHR-BP (OR = 2.9, 95% CI = 1.3-6.7, p = 0.011) had an increased risk of having experienced "severe" PEs compared with controls. In the overall cohort PEs were associated with any lifetime mental disorder, Attention-Deficit/Hyperactivity Disorder, anxiety disorders and a lower level of functioning. The findings of a higher proportion of high risk children reporting PEs could represent an early manifestation of later more severe psychopathology or simply an unspecific transitory symptom. Future follow-up studies of this cohort will explore the predictive value of the occurrence of PEs at age seven.

Confirming diagnostic categories within a depression continuum: Testing extra-linearity of risk factors and a latent class analysis

BACKGROUND

Dimensions are recommended as replacements for diagnostic categories of depression, but clinicians continue to use categories. Categories are appropriate if major, underlying changes in symptom structure occur above a clinical cut-off on a depression continuum.

METHODS

Cross-sectional surveys of Chinese undergraduates (n = 39,446) 2014-2018 measured self-reported depressive symptoms, associated psychopathology and etiological risk factors using standardised instruments. We created a continuum using PHQ-9 scores and tested linear and extra-linear contrasts in associated psychopathology, and etiology. We carried out latent class analyses (LCA).

RESULTS

Most symptoms showed linear increase, but depressed mood, anhedonia, and suicidal ideation showed marked increase at the severe end of the continuum. There was extra-linear increase in associated psychotic symptoms, other psychopathology, age, low family income, chronic pain and physical illness, childhood physical and sexual abuse, and neglect. Four LCs corresponding to Melancholic, Severe melancholic, Non-melancholic, and Mild depression were confirmed, but only above a clinical cut-off along the continuum. Etiological risk factors did not differentiate between classes but showed overall dramatic increase in impact above threshold of clinical severity.

LIMITATIONS

Only one self-report instrument was used (PHQ-9) to measure depression and diagnoses were not validated by clinical interviews.

CONCLUSIONS

Categories are necessary to describe the dramatic changes in underlying structure and symptom associations above a clinical threshold of severity. These result from extra-linear impact of etiological risk factors at the severe end of the depression continuum. Although the study confirmed melancholic and non-melancholic subtypes, further investigation should investigate etiological factors that determine this subdivision.

Timing, Distribution, and Relationship Between Nonpsychotic and Subthreshold Psychotic Symptoms Prior to Emergence of a First Episode of Psychosis

Prospective population studies suggest that psychotic syndromes may be an emergent phenomenon-a function of severity and complexity of more common mental health presentations and their nonpsychotic symptoms. Examining the relationship between nonpsychotic and subthreshold psychotic symptoms in individuals who later developed the ultimate outcome of interest, a first episode of psychosis (FEP), could provide valuable data to support or refute this conceptualization of how psychosis develops. We therefore conducted a detailed follow-back study consisting of semistructured interviews with 430 patients and families supplemented by chart reviews in a catchment-based sample of affective and nonaffective FEP. The onset and sequence of 27 pre-onset nonpsychotic (NPS) or subthreshold psychotic (STPS) symptoms was systematically characterized. Differences in proportions were analyzed with z-tests, and correlations were assessed with negative binomial regressions. Both the first psychiatric symptom (86.24% NPS) and the first prodromal symptom (66.51% NPS) were more likely to be NPS than STPS. Patients reporting pre-onset STPS had proportionally more of each NPS than did those without pre-onset STPS. Finally, there was a strong positive correlation between NPS counts (reflecting complexity) and STPS counts (β = 0.34, 95% CI [0.31, 0.38], P < 2 e-16). Prior to a FEP, NPS precede STPS, and greater complexity of NPS is associated with the presence and frequency of STPS. These findings complement recent arguments that the emergence of psychotic illness is better conceptualized as part of a continuum-with implications for understanding pluripotential developmental trajectories and strengthening early intervention paradigms.

Molecular Genetic Risk for Psychosis Is Associated With Psychosis Risk Symptoms in a Population-Based UK Cohort: Findings From Generation Scotland

OBJECTIVE

Subthreshold psychosis risk symptoms in the general population may be associated with molecular genetic risk for psychosis. This study sought to optimize the association of risk symptoms with genetic risk for psychosis in a large population-based cohort in the UK (N = 9104 individuals 18-65 years of age) by properly accounting for population stratification, factor structure, and sex.

METHODS

The newly expanded Generation Scotland: Scottish Family Health Study includes 5391 females and 3713 males with age M [SD] = 45.2 [13] with both risk symptom data and genetic data. Subthreshold psychosis symptoms were measured using the Schizotypal Personality Questionnaire-Brief (SPQ-B) and calculation of polygenic risk for schizophrenia was based on 11 425 349 imputed common genetic variants passing quality control. Follow-up examination of other genetic risks included attention-deficit hyperactivity disorder (ADHD), autism, bipolar disorder, major depression, and neuroticism.

RESULTS

Empirically derived symptom factor scores reflected interpersonal/negative symptoms and were positively associated with polygenic risk for schizophrenia. This signal was largely sex specific and limited to males. Across both sexes, scores were positively associated with neuroticism and major depressive disorder.

CONCLUSIONS

A data-driven phenotypic analysis enabled detection of association with genetic risk for schizophrenia in a population-based sample. Multiple polygenic risk signals and important sex differences suggest that genetic data may be useful in improving future phenotypic risk assessment.

Maternal cerebellar gray matter volume is associated with daughters' psychotic experience

AIM

A substantial portion of children and adolescents show subthreshold psychotic symptoms called psychotic experience (PE). Because PE shares its biological and environmental risk factors with psychotic spectrum disorders, parental neuroanatomical variation could reflect a heritable biological underpinning of PE that may predict an offspring's PE.

METHODS

A total of 94 participants from 35 families without a diagnosis of major neuropsychiatric disorders were examined, including 14 mother-daughter, 17 mother-son, 12 father-daughter, and 16 father-son dyads. An offspring's PE was assessed with the Atypicality subscale of the Behavior Assessment System for Children - 2nd Edition, Self-Report of Personality form (BASCaty). We examined correlations between voxel-by-voxel parental gray matter volume and their offspring's BASCaty score.

RESULTS

Maternal cerebellar gray matter volume using voxel-based morphometry was positively correlated with their daughters' BASCaty scores. The findings were significant in a more robust approach using cerebellum-specific normalization known. We did not find significant correlation between paternal gray matter volume and BASCaty scores or between offspring gray matter volumes and their BASCaty scores.

CONCLUSION

Expanding upon parent-of-origin effects in psychosis, maternal neuroanatomical variation was associated with daughters' PE. The nature of this sex-specific intergenerational effect is unknown, but maternally transmitted genes may relate cerebellum development to PE pathogenesis.

The Prevalence of Negative Symptoms Across the Stages of the Psychosis Continuum

BACKGROUND

Patients in every stage of the psychosis continuum can present with negative symptoms. While no treatment is currently available to address these symptoms, a more refined characterization of their course over the lifetime could help in elaborating interventions. Previous reports have separately investigated the prevalence of negative symptoms within each stage of the psychosis continuum. Our aim in this review is to compare those prevalences across stages, thereby disclosing the course of negative symptoms.

METHODS

We searched several databases for studies reporting prevalences of negative symptoms in each one of our predetermined stages of the psychosis continuum: clinical or ultra-high risk (UHR), first-episode of psychosis (FEP), and younger and older patients who have experienced multiple episodes of psychosis (MEP). We combined results using the definitions of negative symptoms detailed in the Brief Negative Symptom Scale, a recently developed tool. For each negative symptom, we averaged and weighted by the combined sample size the prevalences of each negative symptom at each stage.

RESULTS

We selected 47 studies totaling 1872 UHR, 2947 FEP, 5039 younger MEP, and 669 older MEP patients. For each negative symptom, the prevalences showed a comparable course. Each negative symptom decreased from the UHR to FEP stages and then increased from the FEP to MEP stages.

CONCLUSIONS

Certain psychological, environmental, and treatment-related factors may influence the cumulative impact of negative symptoms, presenting the possibility for early intervention to improve the long-term course.

Lifetime prevalence and potential determinants of psychotic experiences in the general population of Qatar

BACKGROUND

To estimate the lifetime prevalence and potential determinants of psychotic experience(s) (PEs) in the general population of Qatar - a small non-war afflicted, conservative, high-income, middle-eastern country with recent rapid urbanization including an influx of migrants.

METHODS

A probability-based sample (n = 1353) of non-migrants and migrants were interviewed face-to-face and administered a 7-item psychosis screener adapted from the Composite International Diagnostic Interview, the Kessler 6-item psychological distress scale, and the 5 items assessing odd (paranormal) beliefs and magical thinking (OBMT) from the Schizotypal Personality Questionnaire. Using bivariate and logistic regression analyses, lifetime prevalence rates of PEs were estimated then compared before and after adjustment for socio-demographics, Arab ethnicity, psychological distress, and OBMT.

RESULTS

Prevalence of PEs was 27.9%. Visual hallucinations were most common (12.8%), followed by persecutory delusions (6.7%) and auditory hallucinations (6.9%). Ideas of reference (3.6%) were least prevalent. PEs were significantly higher in Arabs (34.7%) compared with non-Arabs (16.4%, p < 0.001) with the exception of ideas of reference and paranoid delusions. Female gender was associated with a higher prevalence of PEs in the Arab group only (p < 0.001). Prevalence of PEs was significantly higher among Arabs (48.8% v. 15.8%, p < 0.001) and non-Arabs (35.2% v. 7.3%, p < 0.001) with OBMT. Arab ethnicity (OR = 2.10, p = 0.015), psychological distress (OR = 2.29 p = 0.003), and OBMT (OR = 6.25, p < 0.001) were independently associated with PEs after adjustment for all variables.

CONCLUSIONS

Ethnicity, but not migration was independently associated with PEs. Evidence linking Arab ethnicity, female gender, and psychological distress to PEs through associations with OBMT was identified for future prospective investigations.

Terminology and assessment tools of psychosis: A systematic narrative review

AIM

Phenomena within the psychosis continuum that varies in frequency/duration/intensity have been increasingly identified. Different terms describe these phenomena, however there is no standardization within the terminology. This review evaluated the definitions and assessment tools of seven terms - (i) 'psychotic experiences'; (ii) 'psychotic-like experiences'; (iii) 'psychotic-like symptoms'; (iv) 'attenuated psychotic symptoms'; (v) 'prodromal psychotic symptoms'; (vi) 'psychotic symptomatology'; and (vii) 'psychotic symptoms'.

METHODS

EMBASE, MEDLINE, and CINAHL were searched during February-March 2019. Inclusion criteria included 1989-2019, full text, human, and English. Papers with no explicit definition or assessment tool, duplicates, conference abstracts, systematic reviews, meta-analyses, or no access were excluded.

RESULTS

A total of 2238 papers were identified and of these, 627 were included. Definitions and assessment tools varied, but some trends were found. Psychotic experiences and psychotic-like experiences were transient and mild, found in the general population and those at-risk. Psychotic-like symptoms were subthreshold and among at-risk populations and non-psychotic mental disorders. Attenuated psychotic symptoms were subthreshold but associated with distress, risk, and help-seeking. Prodromal psychotic symptoms referred to the prodrome of psychotic disorders. Psychotic symptomatology included delusions and hallucinations within psychotic disorders. Psychotic symptoms was the broadest term, encompassing a range of populations but most commonly involving hallucinations, delusions, thought disorder, and disorganization.

DISCUSSION

A model for conceptualizing the required terms is proposed and future directions needed to advance this field of research are discussed.

Perceived stress and psychosis: The effect of perceived stress on psychotic-like experiences in a community sample of adolescents

AIMS

Psychotic-like experiences (PLE) are sub-threshold, non-clinical forms of psychosis which can place an individual at greater risk of development of a psychotic disorder. Subtypes of PLE have also been shown to exist (bizarre experiences, persecutory ideation, perceptual abnormalities and magical thinking). Perceived stress relates to how two individuals may deal with the same objectively stressful event in different ways. The objective of our study was to investigate the extent to which perceived stress is associated with PLE in a community sample of adolescents, whether certain subtypes of PLE correlate more with perceived stress than others and to explore the role of depression with these associations.

METHODS

A total of 655 students completed the community assessment of psychic experiences (CAPE) and perceived stress scale (PSS). Pearson's correlation was used to investigate the relationship between PSS and CAPE and also between perceived stress and the four subtypes of PLE. Regression then explored the effect of perceived stress on PLE when accounting for depressive symptomatology.

RESULTS

Positive correlation was found between PSS and total CAPE (r = 0.405, P = 0.000). Positive significant correlation was also found between PSS and each subtype of PLE, with persecutory ideation correlating the strongest and magical thinking the least. Perceived stress was significantly associated with PLE even after adjusting for depression.

CONCLUSIONS

We recommend that more regular screening of perceived stress in adolescent populations could lead to earlier recognition of PLE. Early treatment has shown to reduce rates of transition to psychosis, and so could benefit our adolescent community in the future.

Spanish validation of the self-evaluation of negative symptoms scale SNS in an adolescent population

BACKGROUND

Negative symptoms (NS) may be observed in the general population in an attenuated form and in high-risk mental states. However, they have been less studied in the general population than positive symptoms, in spite of their importance at the insidious onset of schizophrenia and their appearance before positive symptoms. This study aimed to analyze the empirical structure of the Spanish version of the Self-Evaluation of Negative Symptoms (SNS) Scale and find its psychometric properties and invariance of measurement across sex and age in a sample of adolescents.

METHODS

The sample consisted of 4521 adolescents (53.6% female) from 11 to 18 years of age.

RESULTS

Confirmatory Factor Analysis of the SNS confirmed an internal structure of five first-order factors by the characteristic dimensions of NS: avolition, social withdrawal, diminished emotional range, anhedonia, alogia, and one second-order factor which includes the total NS score. Multi-group confirmatory factor analysis showed that the scale was invariant across sex and age. Total scale reliability was adequate. A strong relationship was found between the SNS with depressive symptomatology, moderate with ideas of reference and low with aberrant salience.

CONCLUSION

The results back use of the Spanish version of the SNS scale for detection of NS in the general population of adolescents.

Severe childhood trauma and clinical and neurocognitive features in schizotypal personality disorder

OBJECTIVE

Literature suggests that childhood trauma increases vulnerability for schizophrenia-spectrum disorders, including schizotypal personality disorder (SPD). Yet, it remains unexplored whether childhood trauma predicts symptom load and the level of neurocognitive functioning in SPD.

METHOD

We included 225 individuals with SPD and 127 healthy controls. Childhood trauma was evaluated using the Childhood Trauma Questionnaire, and schizotypal traits were assessed using the Schizotypal Personality Questionnaire. Standard neurocognitive assessments covered six cognitive domains.

RESULTS

All types of reported childhood trauma were significantly associated with SPD, in a linear fashion. Severe sexual abuse showed the greatest magnitude of association with higher cognitive-perceptual load (e.g., ideas of reference, odd belief or magical thinking); severe emotional neglect was associated with interpersonal scores (e.g., excessive social anxiety, constricted affect) within the SPD group. SPD individuals who reported severe trauma showed worse cognitive functioning (i.e., working memory, verbal/visual learning and memory, as well as verbal fluency).

CONCLUSIONS

Particular severe childhood trauma types were associated with higher cognitive-perceptual and interpersonal symptoms in SPD, along with worse cognitive functioning. These findings highlight the need for clinicians to enquire about childhood trauma in SPD patients, since unaddressed early adverse experiences may carry long-term negative consequences.

DSM outcomes of psychotic experiences and associated risk factors: 6-year follow-up study in a community-based sample

BACKGROUND

Psychotic experiences (PEs) may predict a range of common, non-psychotic disorders as well as psychotic disorders. In this representative, general population-based cohort study, both psychotic and non-psychotic disorder outcomes of PE were analysed, as were potential moderators.

METHODS

Addresses were contacted in a multistage clustered probability sampling frame covering 11 districts and 302 neighbourhoods at baseline (n = 4011). Participants were interviewed with the Composite International Diagnostic Interview (CIDI) both at baseline and at 6-year follow-up. Participants with PE at baseline were clinically re-interviewed with the SCID-I at follow-up. The role of socio-demographics, characteristics of PE, co-occurrence of mood disorders and family history of mental disorders were tested in the association between baseline PE and follow-up diagnosis.

RESULTS

In the participants with baseline PE, the psychotic disorder diagnosis rate at follow up was 7.0% - much lower than the rates of DSM-IV mood disorders without psychotic features (42.8%) and other non-psychotic disorders (24.1%). Within the group with baseline PE, female sex, lower socio-economic status, co-occurrence of mood disorders, family history of a mental disorder and persistence of PE predicted any follow-up DSM diagnosis. Furthermore, onset of psychotic v. non-psychotic disorder was predicted by younger age (15-30 years), co-presence of delusional and hallucinatory PE and family history of severe mental illness.

CONCLUSION

The outcome of PE appears to be a consequence of baseline severity of multidimensional psychopathology and familial risk. It may be useful to consider PE as a risk indicator that has trans-diagnostic value.

Psychotic-Like Experiences in Offspring of Parents With Bipolar Disorder and Community Controls: A Longitudinal Study

OBJECTIVE

To compare the prevalence and risk factors associated with psychotic-like experiences (PLE) in offspring of parents with bipolar disorder (BP) and offspring of community control parents.

METHOD

Delusional and hallucinatory subclinical psychotic experiences were evaluated at intake and longitudinally in a cohort study of 390 offspring of BP parents and 247 offspring of control parents; all offspring were between 6 and 18 years of age. The sample was followed up every 2.5 years on average for 8.3 years. Of the sample, 91.7% completed at least one follow-up. Risk factors at intake and at each assessment until the onset of PLE were analyzed using survival models.

RESULTS

In all, 95 offspring (14.9%) reported PLE at some point of the study, 16.9% of BP parents and 11.7% of controls, without statistically significant differences. Psychotic disorders were less frequent, with 16 (2.5%) in both groups. During follow-up, three variables remained as the most significant associated with PLE in the multivariate models: (1) presence of any psychiatric disorder (hazard ratio [HR] = 3.1; p = .01); (2) low psychosocial functioning (HR = 2.94; p < .0001); and (3) current or past history of physical or sexual abuse (HR = 1.85; p = .04). There were no effects of any subtype of BP, IQ, history of medical illnesses, exposure to medications, or perinatal complications.

CONCLUSION

In line with previous studies, PLE in our sample were relatively common, and were associated with higher morbidity during the follow-up. Contrary to the literature, neither family risk for bipolar nor early neurodevelopmental insults were associated with PLE.

Childhood Trauma in Schizophrenia: Current Findings and Research Perspectives

Schizophrenia is a severe neuropsychiatric disorder with persistence of symptoms throughout adult life in most of the affected patients. This unfavorable course is associated with multiple episodes and residual symptoms, mainly negative symptoms and cognitive deficits. The neural diathesis-stress model proposes that psychosocial stress acts on a pre-existing vulnerability and thus triggers the symptoms of schizophrenia. Childhood trauma is a severe form of stress that renders individuals more vulnerable to developing schizophrenia; neurobiological effects of such trauma on the endocrine system and epigenetic mechanisms are discussed. Childhood trauma is associated with impaired working memory, executive function, verbal learning, and attention in schizophrenia patients, including those at ultra-high risk to develop psychosis. In these patients, higher levels of childhood trauma were correlated with higher levels of attenuated positive symptoms, general symptoms, and depressive symptoms; lower levels of global functioning; and poorer cognitive performance in visual episodic memory end executive functions. In this review, we discuss effects of specific gene variants that interact with childhood trauma in patients with schizophrenia and describe new findings on the brain structural and functional level. Additive effects between childhood trauma and brain-derived neurotrophic factor methionine carriers on volume loss of the hippocampal subregions cornu ammonis (CA)4/dentate gyrus and CA2/3 have been reported in schizophrenia patients. A functional magnetic resonance imaging study showed that childhood trauma exposure resulted in aberrant function of parietal areas involved in working memory and of visual cortical areas involved in attention. In a theory of mind task reflecting social cognition, childhood trauma was associated with activation of the posterior cingulate gyrus, precuneus, and dorsomedial prefrontal cortex in patients with schizophrenia. In addition, decreased connectivity was shown between the posterior cingulate/precuneus region and the amygdala in patients with high levels of physical neglect and sexual abuse during childhood, suggesting that disturbances in specific brain networks underlie cognitive abilities. Finally, we discuss some of the questionnaires that are commonly used to assess childhood trauma and outline possibilities to use recent biostatistical methods, such as machine learning, to analyze the resulting datasets.

Is BDNF-Val66Met polymorphism associated with psychotic experiences and psychotic disorder outcome? Evidence from a 6 years prospective population-based cohort study

There is little research on genetic risk for the extended psychosis phenotype ranging from psychotic experiences (PEs) to psychotic disorders (PDs). In this general population-based prospective cohort study, the longitudinal associations between BDNF-Val66Met polymorphism and the different levels of the extended psychosis phenotype were investigated. Addresses were contacted in a multistage clustered probability sampling frame covering 11 districts and 302 neighborhoods at baseline (n = 4011). A nested case-control study (n = 366) recruited individuals with PEs and PDs as well as individuals with no psychotic symptoms. In this subgroup, blood sampling for genetic analysis and assessment of environmental exposures were carried out, followed by clinical re-appraisal at follow-up 6 years later (n = 254). The BDNF-Val66Met polymorphism was significantly associated with the extended psychosis phenotype. The pattern of the association was that the BDNF-Val66Met polymorphism impacted in a dose-response but extra-linear fashion, with stronger impact at the PD end of the extended psychosis phenotype. Associations were still significant after adjusting for sociodemographic factors and environmental exposures including life events, childhood adversity, socioeconomic status, urbanicity, and cannabis use. The BDNF-Val66Met polymorphism may index susceptibility to expression of psychosis along a spectrum.

Ethnic minority position and migrant status as risk factors for psychotic symptoms in the general population: a meta-analysis

Psychotic symptoms (PS) are experienced by a substantial proportion of the general population. When not reaching a threshold of clinical relevance, these symptoms are defined as psychotic experiences (PEs) and may exist on a continuum with psychotic disorders. Unfavorable socio-environmental conditions, such as ethnic minority position (EMP) and migrant status (MS), may increase the risk of developing PS and PEs. We conducted an electronic systematic review and a meta-analysis assessing the role of EMP and MS for the development and persistence of PS in the general population. Sub-group analyses were performed investigating the influence of ethnic groups, host countries, age, types of PS, and scales. Twenty-four studies met our inclusion criteria. EMP was a relevant risk factor for reporting PS [odds ratio (OR) 1.44, 95% confidence interval (CI) 1.22-1.70) and PEs (OR 1.36, 95% CI 1.16-1.60). The greatest risk was observed in people from the Maghreb and the Middle East ethnic groups in Europe (OR 3.30, 95% CI 2.09-5.21), in Hispanic in the USA (OR 1.98, 95% CI 1.43-2.73), and in the Black populations (OR 1.85, 95% CI 1.39-2.47). We found a significant association between MS and delusional symptoms (OR 1.47, 95% CI 1.33-1.62). We found no association between EMP and persistence of PEs.EMP was associated with increased risk of reporting PS and PEs, and the risk was higher in ethnic groups facing deprivation and discrimination. We found an association between MS and delusional symptoms. These results raise questions about the precise role of socio-environmental factors along the psychosis continuum.

Psychotic experiences and mood episodes predict each other bidirectionally: a 6-year follow-up study in a community-based population

BACKGROUND

Psychotic experiences (PEs) are not exclusive to psychotic disorders and highly correlated with mood episodes. In this representative general population-based study, longitudinal bidirectional associations between the extended psychosis phenotype and mood episodes were investigated, accounting for other possible causes.

METHODS

Households were contacted in a multistage clustered probability sampling frame covering 11 districts and 302 neighbourhoods at baseline (n = 4011) and at 6-year follow-up (n = 2185). Participants were interviewed with the relevant sections of the composite international diagnostic interview both at baseline and at follow-up. Sociodemographic, familial and environmental risk factors associated with the extended psychosis phenotype and mood episodes were assessed. Logistic regression and cross-lagged panel correlation models were used for the associations between the extended psychosis phenotype and mood episodes.

RESULTS

PEs were associated with subsequent depressive and manic episodes. There was bidirectionality in that mood episodes were associated with subsequent PEs, and PEs were associated with subsequent mood episodes. The associations occurred in a sub-additive pattern. There were substantial synchronous and cross-lagged correlations between these psychopathology domains, with reciprocally similar cross-lagged correlations. Familial risk and adverse life events were associated with both psychopathology domains, whereas some sociodemographic risk factors and alcohol/cannabis use were associated with only one domain.

CONCLUSION

The sub-additive bidirectional associations between PEs and mood episodes over time and the similarity of cross-lagged correlations are suggestive of mutually causal connections between affective and psychotic domains of psychopathology.

Izmir Mental Health Cohort for Gene-Environment Interaction in Psychosis (TürkSch): Assessment of the Extended and Transdiagnostic Psychosis Phenotype and Analysis of Attrition in a 6-Year Follow-Up of a Community-Based Sample

Objective: TürkSch is a prospective, longitudinal study in a representative community sample (İzmir, Turkey), consisting of several data collection stages, to screen and follow-up mental health outcomes, with a special focus on the extended and transdiagnostic psychosis phenotype. The aim of the present paper is to describe the research methodology, data collection results, and associations with noncontact and refusal in the longitudinal arm. Methods: Households were contacted in a multistage clustered probability sampling frame, covering 11 districts and 302 neighborhoods at baseline (n = 4,011) and at 6-year follow-up (n = 2,185). Both at baseline and at follow-up, participants were interviewed with the Composite International Diagnostic Interview. Participants with probable psychotic disorder were reinterviewed with the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (SCID)-I either at the hospital or at the participant's residence. Relevant neighborhood-level measures were assessed in a separate sample (n = 5,124) in addition to individual-level measures. Candidate gene-by-environment interactions were investigated using two nested case-control studies. Results: Individuals with a mental health problem had lower refusal rates. Older and lower educated individuals had a lower probability of noncontact. Discussion: The TürkSch study has an advanced design to meet the challenges of evaluating the multidimensional etiological and phenomenological nature of the extended and transdiagnostic psychosis phenotype.

Subclinical psychosis in adult migrants and ethnic minorities: systematic review and meta-analysis

BACKGROUND

It is well established that migration and ethnic minority status are risk factors for psychotic disorders. Recent studies have aimed to determine if they are also associated with subclinical psychosis (psychotic-like experiences and schizotypal traits).

AIMS

We aimed to determine to what extent migrant and ethnic minority groups are associated with higher risk of subclinical psychosis.

METHOD

We conducted a systematic review, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, and examined findings by ethnicity, migrant status, outcomes of subclinical psychosis and host country. A meta-analysis was carried out with robust variance estimation where possible, to handle statistically dependent effect size estimates.

RESULTS

We included 28 studies (19 studies on psychotic-like experiences and 9 studies on schizotypal traits) and found that ethnicity, but not migrant status, was associated with current and lifetime psychotic-like experiences. In the narrative analysis, we observed the effect of psychosocial risk factors on this association: Black ethnicity groups showed consistent increased prevalence of current and lifetime psychotic-like experiences compared with the reference population across countries.

CONCLUSIONS

More generalisable and standardised cohort studies of psychotic-like experiences and schizotypal traits in relation to migration/ethnicity are necessary to examine the effects of exposures and outcomes in different contexts, and to understand the underlying mechanisms of the association between subclinical psychosis and migrant and ethnic minority status.

DECLARATION OF INTEREST

None.

Increased Resting Hippocampal and Basal Ganglia Perfusion in People at Ultra High Risk for Psychosis: Replication in a Second Cohort

We recently reported that resting hippocampal, basal ganglia and midbrain perfusion is elevated in people at ultra high risk (UHR) for psychosis. The present study sought to replicate our previous finding in an independent UHR cohort, and examined the relationship between resting perfusion in these regions, psychosis and depression symptoms, and traumatic experiences in childhood. Pseudo-Continuous Arterial Spin Labelling (p-CASL) imaging was used to measure resting cerebral blood flow (rCBF) in 77 UHR for psychosis individuals and 25 healthy volunteers in a case-control design. UHR participants were recruited from clinical early detection services at 3 sites in the South of England. Symptoms levels were assessed using the Comprehensive Assessment of At Risk Mental States (CAARMS), the Hamilton Depression Scale (HAM-D), and childhood trauma was assessed retrospectively using the Childhood Trauma Questionnaire (CTQ). Right hippocampal and basal ganglia rCBF were significantly increased in UHR subjects compared to controls, partially replicating our previous finding in an independent cohort. In UHR participants, positive symptoms were positively correlated with rCBF in the right pallidum. CTQ scores were positively correlated with rCBF values in the bilateral hippocampus and negatively associated with rCBF in the left prefrontal cortex. Elevated resting hippocampal and basal ganglia activity appears to be a consistent finding in individuals at high risk for psychosis, consistent with data from preclinical models of the disorder. The association with childhood trauma suggests that its influence on the risk of psychosis may be mediated through an effect on hippocampal function.

A systematic review of genome-wide research on psychotic experiences and negative symptom traits: new revelations and implications for psychiatry

We present a systematic review of genome-wide research on psychotic experience and negative symptom (PENS) traits in the community. We integrate these new findings, most of which have emerged over the last four years, with more established behaviour genetic and epidemiological research. The review includes the first genome-wide association studies of PENS, including a recent meta-analysis, and the first SNP heritability estimates. Sample sizes of <10 000 participants mean that no genome-wide significant variants have yet been replicated. Importantly, however, in the most recent and well-powered studies, polygenic risk score prediction and linkage disequilibrium (LD) score regression analyses show that all types of PENS share genetic influences with diagnosed schizophrenia and that negative symptom traits also share genetic influences with major depression. These genetic findings corroborate other evidence in supporting a link between PENS in the community and psychiatric conditions. Beyond the systematic review, we highlight recent work on gene-environment correlation, which appears to be a relevant process for psychotic experiences. Genes that influence risk factors such as tobacco use and stressful life events are likely to be harbouring 'hits' that also influence PENS. We argue for the acceptance of PENS within the mainstream, as heritable traits in the same vein as other sub-clinical psychopathology and personality styles such as neuroticism. While acknowledging some mixed findings, new evidence shows genetic overlap between PENS and psychiatric conditions. In sum, normal variations in adolescent and adult thinking styles, such as feeling paranoid, are heritable and show genetic associations with schizophrenia and major depression.

Evidence That Environmental and Familial Risks for Psychosis Additively Impact a Multidimensional Subthreshold Psychosis Syndrome

BACKGROUND

The observed link between positive psychotic experiences (PE) and psychosis spectrum disorder (PSD) may be stronger depending on concomitant presence of PE with other dimensions of psychopathology. We examined whether the effect of common risk factors for PSD on PE is additive and whether the impact of risk factors on the occurrence of PE depends on the co-occurrence of other symptom dimensions (affective dysregulation, negative symptoms, and cognitive alteration).

METHOD

Data from the Netherlands Mental Health Survey and Incidence Study 2 were used. Risk factors included childhood adversity, cannabis use, urbanicity, foreign born, hearing impairment, and family history of affective disorders. Logistic regression models were applied to test (1) the additive effect of risk factors (4 levels) on PE and (2) the moderating effects of symptom dimensions on the association between risk factors (present/absent) and PE, using additive interaction, expressed as the interaction contrast ratio.

RESULTS

Risk factors were additive: the greater the number of risk factors, the greater the odds of PE. Furthermore, concomitant presence of the other symptom dimensions all increased the impact of risk factors on PE. After controlling for age, sex, and education, only affective dysregulation and negative symptoms remained significant moderators; only affective dysregulation remained a significant moderator if all dimensions were adjusted for each other.

CONCLUSIONS

Risk factors may not be directly associated with PE but additively give rise to a multidimensional subthreshold state anticipating the multidimensional clinical syndrome. Early motivational and cognitive impairments in the context of PE may be reducible to affective dysregulation.

Higher schizotypy predicts better metabolic profile in unaffected siblings of patients with schizophrenia

RATIONALE

Type 2 diabetes (T2D) is more frequent in schizophrenia (Sz) than in the general population. This association is partly accounted for by shared susceptibility genetic variants.

OBJECTIVE

We tested the hypotheses that a genetic predisposition to Sz would be associated with higher likelihood of insulin resistance (IR), and that IR would be predicted by subthreshold psychosis phenotypes.

METHODS

Unaffected siblings of Sz patients (n = 101) were compared with a nonclinical sample (n = 305) in terms of IR, schizotypy (SzTy), and a behavioural experiment of "jumping to conclusions". The measures, respectively, were the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), Structured Interview for Schizotypy-Revised (SIS-R), and the Beads Task (BT). The likelihood of IR was examined in multiple regression models that included sociodemographic, metabolic, and cognitive parameters alongside group status, SIS-R scores, and BT performance.

RESULTS

Insulin resistance was less frequent in siblings (31.7%) compared to controls (43.3%) (p < 0.05), and negatively associated with SzTy, as compared among the tertile groups for the latter (p < 0.001). The regression model that examined all relevant parameters included the tSzTy tertiles, TG and HDL-C levels, and BMI, as significant predictors of IR. Lack of IR was predicted by the highest as compared to the lowest SzTy tertile [OR (95%CI): 0.43 (0.21-0.85), p = 0.015].

CONCLUSION

Higher dopaminergic activity may contribute to both schizotypal features and a favourable metabolic profile in the same individual. This is compatible with dopamine's regulatory role in glucose metabolism via indirect central actions and a direct action on pancreatic insulin secretion. The relationship between dopaminergic activity and metabolic profile in Sz must be examined in longitudinal studies with younger unaffected siblings.

Genome-Wide Association Study of Psychosis Proneness in the Finnish Population

The current study examined quantitative measures of psychosis proneness in a nonpsychotic population, in order to elucidate their underlying genetic architecture and to observe if there is any commonality to that already detected in the studies of individuals with overt psychotic conditions, such as schizophrenia and bipolar disorder. Heritability, univariate and multivariate genome-wide association (GWAs) tests, including a series of comprehensive gene-based association analyses, were developed in 4269 nonpsychotic persons participating in the Northern Finland Birth Cohort 1966 study with information on the following psychometric measures: Hypomanic Personality, Perceptual Aberration, Physical and Social Anhedonia (also known as Chapman's Schizotypia scales), and Schizoidia scale. Genome-wide genetic data was available for ~9.84 million SNPs. Heritability estimates ranged from 16% to 27%. Phenotypic, genetic and environmental correlations ranged from 0.04-0.43, 0.25-0.73, and 0.12-0.43, respectively. Univariate GWAs tests revealed an intronic SNP (rs12449097) at the TMC7 gene (16p12.3) that significantly associated (P = 3.485 × 10-8) with the hypomanic scale. Bivariate GWAs tests including the hypomanic and physical anhedonia scales suggested a further borderline significant SNP (rs188320715; P-value = 5.261 × 10-8, ~572 kb downstream the ARID1B gene at 6q25.3). Gene-based tests highlighted 20 additional genes of which 5 had previously been associated to schizophrenia and/or bipolar disorder: CSMD1, CCDC141, SLC1A2, CACNA1C, and SNAP25. Altogether the findings explained from 3.7% to 14.1% of the corresponding trait heritability. In conclusion, this study provides preliminary genomic evidence suggesting that qualitatively similar biological factors may underlie different psychosis proneness measures, some of which could further predispose to schizophrenia and bipolar disorder.