A systematic review and meta-analysis of the psychosis continuum: evidence for a psychosis proneness-persistence-impairment model of psychotic disorder

Lifetime prevalence of psychotic-like experiences and associated factors in Chile

INTRODUCTION

Psychotic-like experiences (PLEs), which include hallucinations and delusional experiences, are usually present in healthy populations, and their persistence, quality, and severity are associated with the development of psychiatric diseases, including schizophrenia and other poor psychosocial outcomes. Urbanicity, depression, and other psychosocial stressors have been associated with PLEs. However, evidence of PLEs in Latin American (LATAM) countries is still scarce, and there are no studies about PLEs in Chile. The main aim of this study is to describe the prevalence of PLEs in a nationally representative sample according to other social determinants of health.

METHODS

The last results of the Chilean National Health Survey (ENS 2016-2017) were analyzed. PLEs were obtained from the Composite International Diagnostic Interview (CIDI) 3.0 and included in this survey. Other psychosocial variables (age, sex, educational level, financial stress, depressive symptoms, and urbanicity) were also included for further analysis. Exclusion criteria were (1) >  = 65 and < 18 years old, and (2) previous diagnosis or treatment for schizophrenia or bipolar disorder. Descriptive statistics were used to describe data, and Poisson regression models were performed to weight variables and find psychosocial correlations with PLEs.

RESULTS

2095 subjects were considered for this study (women 62.9% and mean age = 42.5, SD = 13.5). The lifetime prevalence of the PLEs (> = 1 PLE) in Chile was 12.9%. Visual hallucinations were the most common PLE (9.6%), and ideas of reference were the least common (0.4%). The Poisson regression model showed a higher prevalence of PLEs in the Gran Concepción conurbation (OR = 2.56) and Gran Valparaíso conurbation (OR = 1.69) compared with non-big cities. On the other hand, the 18-24 year group had higher PLEs prevalence compared to other age groups. No correlations were found with educational status, financial stress, or depressive symptoms.

CONCLUSIONS

A relatively high prevalence of PLEs was found in the Chilean general population, particularly in youth living in large urban areas (Gran Valparaíso and Gran Concepción), which is compatible with previous research. Considering that there were no correlations between low educational level and financial or depressive symptoms, it is necessary to have more studies that correlate other urban relevant variables, such as natural disasters, drug consumption, and domestic or neighborhood violence.

Variability in white matter structure relates to hallucination proneness

Hallucinations are a prominent transdiagnostic psychiatric symptom but are also prevalent in individuals who do not require clinical care. Moreover, persistent psychosis-like experience in otherwise healthy individuals may be related to an increased risk to transition to a psychotic disorder. This suggests a common etiology across clinical and non-clinical individuals along a multidimensional psychosis continuum that may be detectable in structural variations of the brain. The current diffusion tensor imaging study assessed 50 healthy individuals (35 females) to identify possible differences in white matter associated with hallucination proneness (HP). This approach circumvents potential confounds related to medication, hospitalization, and disease progression common in clinical individuals. We determined how HP relates to white matter structure in selected association, commissural, and projection fiber pathways putatively linked to psychosis. Increased HP was associated with enhanced fractional anisotropy (FA) in the right uncinate fasciculus, the right anterior and posterior arcuate fasciculus, and the corpus callosum. These findings support the notion of a psychosis continuum, providing first evidence of structural white matter variability associated with HP in healthy individuals. Furthermore, alterations in the targeted pathways likely indicate an association between HP-related structural variations and the putative salience and attention mechanisms that these pathways subserve.

Psychotic experiences and dissociation in adolescents: Within-person analysis in the Tokyo teen cohort

Although many cross-sectional studies showed that psychotic experiences (PEs) and dissociation were closely related, the longitudinal association between them remains unknown. Therefore, the aim of the current study was to examine the longitudinal association of these two symptoms throughout adolescence, under the hypothesis that these two symptoms are bidirectionally associated. Data were obtained from a population-based cohort, the Tokyo Teen Cohort study (TTC; N = 3171). PEs and dissociation were assessed at 10, 12, 14, and 16 years of age. PEs were assessed using a total score from five-item self-report questionnaires derived from the Diagnostic Interview Schedule for Children (DISC-C). Dissociation was assessed using subscale scores of the Child Behavior Checklist (CBCL) completed by primary caregivers. We examined the longitudinal relationship between PEs and dissociation using the random intercept cross-lagged panel model (RI-CLPM). The within-person component of the RI-CLPM revealed no significant cross-lagged effect of dissociation on PEs at any time point. On the other hand, there was a significant (p < 0.05) association between PEs at age 14 and dissociation at age 16 (β = 0.106, 95 % CI 0.047-0.165). The between-person component revealed a significant time-invariant relationship between the two symptoms (β = 0.324, 95 % CI 0.239-0.410). The longitudinal relationship between PEs and dissociation was limited at the within-person level, whereas the between-person correlation was significant. The only significant longitudinal pathway was from PEs to dissociation, suggesting that PEs may be a predictor of dissociation in mid-adolescence.

Season of birth and schizotypy in a sample of undergraduate students

PURPOSE

In line with the psychotic continuum theory, the study of psychometric schizotypy in non-clinical samples has been proposed as a convenient yet powerful method for studying the etiology of psychosis. Based on this paradigm, several studies explored the association between season of birth (SoB) and schizotypy but led to inconsistent results. Building on the analysis of the previous studies, in the present study, we aimed to advance our understanding by improving the methodology (using a homogeneous group, eliminating unreliable respondents, taking into account potential confounders) and the reporting.

METHODS

Subjects were recruited among undergraduate students from 3 Romanian Universities. To limit the potential influence of invalid response, we applied methods for detecting unreliable and/or biased questionnaires and excluded subjects with unreliable/ biased answers from the analyses. Schizotypal dimensions were measured using the Romanian translation of the 22-items Schizotypal Personality Questionnaire-Brief (SPQ-B). The association between schizotypy scores and season of birth was explored using linear regression.

RESULTS

In a sample of 484 undergraduate students from Romania, we found that being born in late winter/early spring (February and March) was associated to higher total schizotypy score and disorganization. Furthermore, we found that restricting the sample to subjects born in an urban environment increased the strength of the association.

CONCLUSION

This study is consistent with an association between SoB and the risk of psychotic disorders.

Associations of Cognitive Expectancies With Auditory Hallucinations and Hallucinatory-Like Experiences in Patients With Schizophrenia

BACKGROUND

Various neurocognitive models explore perceptual distortions and hallucinations in schizophrenia and the general population. A variant of predictive coding account suggests that strong priors, like cognitive expectancy, may influence perception. This study examines if stronger cognitive expectancies result in more auditory false percepts in clinical and healthy control groups, investigates group differences, and explores the association between false percepts and hallucinations.

STUDY DESIGN

Patients diagnosed with schizophrenia with current auditory hallucinations (n = 51) and without hallucinations (n = 66) and healthy controls (n = 51) underwent the False Perception Task under various expectancy conditions. All groups were examined for the presence and severity of hallucinations or hallucinatory-like experiences.

STUDY RESULTS

We observed a main effect of condition across all groups, ie, the stronger the cognitive expectancy, the greater the ratio of auditory false percepts. However, there was no group effect for the ratio of auditory false percepts. Despite modest pairwise correlations in the hallucinating group, the ratio of auditory false percepts was not predicted by levels of hallucinations and hallucinatory-like experiences in a linear mixed model.

CONCLUSIONS

The current study demonstrates that strong priors in the form of cognitive expectancies affect perception and play a role in perceptual disturbances. There is also a tentative possibility that overreliance on strong priors may be associated with hallucinations in currently hallucinating subjects. Possible, avoidable confounding factors are discussed in detail.

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.

Relationship between social cognition and emotional markers and acoustic-verbal hallucination in youth with post-traumatic stress disorder: Protocol for a prospective, 2-year, longitudinal case-control study

INTRODUCTION

Auditory-verbal hallucinatory experiences (AVH) have a 12% prevalence in the general pediatric population. Literature reports a higher risk of developing AVH in post-traumatic stress disorder (PTSD). The persistence of AVHs during adolescence represents a risk of evolution into psychotic disorders. Social cognition and emotional markers could be considered prodromes markers of this evolution. The objectives of this prospective observational study are to observe social cognition and emotional markers correlation with the presence and persistence of AVH over two years and with the evolution of PTSD and psychotic diagnosis.

METHODS AND ANALYSIS

This prospective case-control study, longitudinal over two years (with an interim reassessment at six months and one year), will include 40 participants aged 8 to 16 years old with a diagnosis of PTSD and without a diagnosis of psychosis according to the criteria of DSM-5 (K-SADS-PL). Subjects included are divided into two groups with AVH and without AVH matched by gender, age and diagnosis. The primary outcome measure will be the correlation between social cognition and emotional makers and the presence of AVH in the PTSD pediatric population without psychotic disorders. The social cognition marker is assessed with the NEPSY II test. The emotional marker is assessed with the Differential Emotion Scale IV and the Revised Beliefs About Voices Questionnaire. The secondary outcome measures are the correlation of these markers with the persistence of AVH and the evolution of the patient's initial diagnosis two years later.

DISCUSSION

The originality of our protocol is to explore the potential progression to psychosis from PTSD by cognitive biases. This study supports the hypothesis of connections between PTSD and AVH through sensory, emotional and cognitive biases. It proposes a continuum model from PTSD to psychotic disorder due to impaired perception like AVH.

TRIAL REGISTRATION

Clinical trial registration: ClinicalTrials.gov Identifier: NCT03356028.

Plasma complement and coagulation proteins as prognostic factors of negative symptoms: An analysis of the NAPLS 2 and 3 studies

INTRODUCTION

Negative symptoms impact the quality of life of individuals with psychosis and current treatment options for negative symptoms have limited effectiveness. Previous studies have demonstrated that complement and coagulation pathway protein levels are related to later psychotic experiences, psychotic disorder, and functioning. However, the prognostic relationship between complement and coagulation proteins and negative symptoms is poorly characterised.

METHODS

In the North American Prodrome Longitudinal Studies 2 and 3, negative symptoms in 431 individuals at clinical high-risk for psychosis (mean age: 18.2, SD 3.6; 42.5 % female) were measured at multiple visits over 2 years using the Scale of Psychosis-Risk Symptoms. Plasma proteins were quantified at baseline using mass spectrometry. Four factors were derived to represent levels of proteins involved in the activation or regulation of the complement or coagulation systems. The relationships between standardised protein group factors and serial measurements of negative symptoms over time were modelled using generalised least squares regression. Analyses were adjusted for baseline candidate prognostic factors: negative symptoms, positive symptoms, functioning, depressive symptoms, suicidal ideation, cannabis use, tobacco use, antipsychotic use, antidepressant use, age, and sex.

RESULTS

Clinical and demographic prognostic factors of follow-up negative symptoms included negative, positive, and depressive symptoms, functioning, and age. Adjusting for all candidate prognostic factors, the complement regulators group and the coagulation regulators group were identified as prognostic factors of follow-up negative symptoms (β: 0.501, 95 % CI: 0.160, 0.842; β: 0.430, 95 % CI: 0.080, 0.780 respectively. The relationship between complement regulator levels and negative symptoms was also observed in NAPLS2 alone (β: 0.501, 95 % CI: -0.037, 1.039) and NAPLS3 alone, additionally adjusting for BMI (β: 0.442, 95 % CI: 0.127, 0.757).

CONCLUSION

The results indicate that plasma complement and coagulation regulator levels are prognostic factors of negative symptoms, independent of clinical and demographic prognostic factors. These results suggest complement and coagulation regulator levels could have potential utility in informing treatment decisions for negative symptoms in individuals at risk.

Functional network characteristics in adolescent psychotic mood disorder: associations with symptom severity and treatment effects

Adolescent psychotic mood disorder (MDP) is a specific phenotype that characterized by more severe symptoms and prognosis compared to nonpsychotic mood disorder (MDNP). But the underlying neural mechanisms remain unknown, and graph theory analysis can help to understand possible mechanisms of psychotic symptoms from the perspective of functional networks. A total of 177 adolescent patients with mood disorders were recruited, including 61 MDP and 116 MDNP. Functional networks were constructed, and topological properties were compared between the two groups at baseline and after treatment, and the association between properties changes and symptom improvement was explored. Compared to the MDNP group, the MDP group exhibited higher small-world properties (FDR q = 0.003) and normalized clustering coefficients (FDR q = 0.008) but demonstrated decreased nodal properties in the superior temporal gyrus (STG), Heschl's gyrus, and medial cingulate gyrus (all FDR q < 0.05). These properties were found to be correlated with the severity of psychotic symptoms. Topological properties also changed with improvement of psychotic symptoms after treatment, and changes in degree centrality of STG in the MDP was significantly positive correlated with improvement of psychotic symptoms (r = 0.377, P = 0.031). This study indicated that functional networks are more severely impaired in patients with psychotic symptoms. Topological properties, particularly those associated with the STG, hold promise as emerging metrics for assessing symptoms and treatment efficacy in patients with psychotic symptoms.

Sociodemographic and clinical correlates of hallucinations in patients entering an early intervention program for first episode psychosis

Hallucinations are a core feature of psychosis, and their severity during the acute phase of illness is associated with a range of poor outcomes. Various clinical and sociodemographic factors may predict hallucinations and other positive psychotic symptoms in first episode psychosis (FEP). Despite this, the precise factors associated with hallucinations at first presentation to an early intervention service have not been extensively researched. Through detailed interviews and chart reviews, we investigated sociodemographic and clinical predictors in 636 minimally-medicated patients who entered PEPP-Montréal, an early intervention service for FEP, between 2003 and 2018. Hallucinations were measured using the Scale for the Assessment of Positive Symptoms (SAPS), while negative symptoms were assessed using the Scale for the Assessment of Negative symptoms (SANS). Depressive symptoms were evaluated through the Calgary Depression Scale for Schizophrenia (CDSS), and anxiety symptoms via the Hamilton Rating Scale for Anxiety (HAS). A majority (n = 381, 59.9 %) of the sample presented with clinically significant hallucinations (SAPS global hallucinations score ≥ 3) at program entry. These patients had an earlier age at onset, fewer years of education, and a higher severity of delusions, depression and negative symptoms than those without clinical-level hallucinations. These results suggest that individuals with clinically significant hallucinations at admission tend to be younger and have a greater overall symptom burden. This makes it especially important to monitor hallucinations alongside delusions, depression and negative symptoms in order to identify who might benefit from targeted interventions. The implications of these findings for early intervention and person-centered care are discussed.

Screening for psychosis risk in primary mental health care services - Implementation, prevalence and recovery trajectories

OBJECTIVES

Early interventions improve outcomes for people at high risk of psychosis and are likely to be cost saving. This group tends to seek help for emotional problems - depression and anxiety - via primary care services, where early detection methods are poor. We sought to determine prevalence rates of high risk for psychosis in UK primary care mental health services and clinical outcomes following routinely delivered psychological therapies.

METHODS

We used a brief screen designed for settings with low base rates and significant time constraints to determine prevalence of high risk for psychosis in UK 'Talking Therapies' services. We examined socio-demographic characteristics, presenting problems and recovery trajectories for this group, compared with people not at risk of psychosis.

RESULTS

A 2-item screen selected for specificity yielded a prevalence rate of 3% in primary care mental health services. People at elevated risk of psychosis were younger and more likely to report at least one long-term physical condition. This group presented with higher levels of depression, anxiety and trauma symptoms at assessment and were less likely to have recovered at the end of treatment, compared to people not at risk.

CONCLUSIONS

Very brief screening tools can be implemented in busy health care settings. The 3% of referrals to UK primary care psychological therapies services at elevated risk of psychosis typically present with more severe symptoms and greater levels of comorbidity and may require augmented interventions to recover fully.

Loneliness and psychotic-like experiences in middle-aged and older adults: the mediating role of selective attention to threat and external attribution biases

OBJECTIVES

Loneliness has been associated with psychotic-like experiences (PLEs) in the general population, but the mechanisms underlying this association are poorly understood. Theoretical models, corroborated by empirical findings, signify the key role of biased cognition in both loneliness and psychosis. This study tested whether two cognitive biases - Selective Attention to Threat (ATB) and External Attribution Bias (EAB) - account for the association between loneliness and PLEs.

METHOD

A convenience sample (n = 357) of middle-aged and older adults (aged 40+) was recruited online from the UK population. The parallel mediation model with two the aforementioned cognitive biases as mediators was tested.

RESULTS

A mediation effect between loneliness and PLEs via ATB (ab1 = 0.441, 95% CI = [0.264, 0.646]) and EAB (ab2 = 0.354, 95% CI [0.124, 0.627] was established. This model remained significant after controlling for the current symptoms of anxiety and depression.

CONCLUSION

Greater loneliness was associated with a higher rate of PLEs in the sample of middle-aged and older adults. This association was fully explained by ATB and EAB, independent of the current symptoms of anxiety and depression.

Immersive virtual reality as a novel approach to investigate the association between adverse events and adolescent paranoid ideation

PURPOSE

Paranoid ideation is common among adolescents, yet little is known about the precursors. Using a novel immersive virtual reality (VR) paradigm, we tested whether experiences of bullying, and other interpersonal/threatening events, are associated with paranoid ideation to a greater degree than other types of (i) non-interpersonal events or (ii) adverse childhood experiences.

METHODS

Self-reported exposure to adverse life events and bullying was collected on 481 adolescents, aged 11-15. We used mixed effects (multilevel) linear regression to estimate the magnitude of associations between risk factors and paranoid ideation, assessed by means of adolescents' reactions to ambiguously behaving avatars in a VR school canteen, adjusting for putative confounders (gender, year group, ethnicity, free school meal status, place of birth, family mental health problems).

RESULTS

Lifetime exposure to interpersonal/threatening events, but not non-interpersonal events or adverse circumstances, was associated with higher levels of state paranoid ideation, with further evidence that the effect was cumulative (1 type: ϐadj 0.07, 95% CI -0.01-0.14; 2 types: ϐadj 0.14, 95% CI 0.05-0.24; 3 + types: ϐadj 0.24, 95% CI 0.12-0.36). More tentatively, for girls, but not boys, recent bullying was associated with heightened paranoid ideation with effect estimates ranging from ϐadj 0.06 (95% CI -0.02-0.15) for physical bullying to ϐadj 0.21 (95% CI 0.10-0.32) for cyber bullying.

CONCLUSIONS

Our data suggest a degree of specificity for adversities involving interpersonal threat or hostility, i.e. those that involve unwanted interference and/or attempted control of an individual's personal boundaries being associated with heightened levels of state paranoid ideation among adolescents.

Psychotic-like experiences in a nationally representative study of general population adolescents

BACKGROUND

Subclinical psychotic-like experiences (PLEs) are common among general population adolescents but have been found to correlate with various problems in well-being. Due to limited sample sizes these effects have not been well differentiated by sex and age.

METHODS

Using a nationally representative survey of almost 160,000 adolescents, we studied endorsement and correlates of PLEs by sex among middle adolescence pupils (ages 14-16) and late adolescence students (ages 16-20). PLEs were investigated with three questionnaire items: auditory and visual hallucinatory experiences and suspicious thought content, using a frequency response scale.

RESULTS

Weekly PLEs were reported by 14 % of the adolescents, more often in females (17 %) than males (11 %) and in the younger age group (17 %) compared to the older adolescents (10 %). A latent PLE factor represented the three assessed PLEs with good fit. Factor scores were highest for the younger females and lowest for the older males. The PLE factor correlated with two latent factors of other well-being, namely living environment ("adversity", loading most heavily on parental mental abuse; r = 0.63), and concurrent mental health ("distress", loading most heavily on depressive symptoms; r = 0.50). Adversity was associated especially strongly with PLEs in 14-16-year-old males.

CONCLUSIONS

This cross-sectional study reaching the whole 14-20 age group in schools in Finland offers data on the meaning and relevance of PLEs as general markers of vulnerability. Many adolescents experience PLEs recurrently and these experiences are associated with a wide variety of burden in the adolescent's everyday life.

Factors associated with the psychosis continuum among homeless people: Comparison between natives and migrants in the SAMENTA study

Background

In the last decades, there has been a documented increase in the proportion of migrants among homeless people in Europe. While homelessness is associated with psychosis, little is known about the factors associated with psychosis among migrants in this context.

Methods

Our study analyzed data collected in the SAMENTA cross-sectional survey conducted among 859 adult French-speaking homeless people living in the Greater Paris area. We analyzed the prevalence of psychosis and psychotic-like experiences (PLE) and associated factors by migrant status, using bivariate analysis and multivariable logistic regression models.

Results

Our sample comprised 280 natives and 559 migrants in France. Psychosis was significantly more prevalent among natives (21.6 %) than among migrants (7.5 %) (p = 0.003). The total prevalence of PLE was 30.8% (95 % CI: 24.3 - 38.2), and not statistically different between groups (p = 0.215) or sex (p = 0.528). Adverse events over the past year were associated with the increased odds of psychosis in both groups and with PLE among migrants. Sexual abuse during childhood was associated with both outcomes among natives. Among migrants, exposure to war or life-threatening events increased the odds of psychosis and PLE. Increased odds of psychosis were found among migrants who had been living in France for more than 10 years (OR = 3.34, 95 % CI: 1.41-7.93, p = 0.007).

Conclusion

Differences were found in the factors associated with the psychosis continuum by migrant status, they highlight the impact of experiences related to migration. Prospective studies are needed to better understand these underlying pathways.

Taking the edge off: a feasibility randomized controlled trial of an online mindfulness-based intervention to reduce suspiciousness/paranoia in high positive schizotypy

Positive schizotypy can uniquely predict the development of psychosis with suspiciousness/paranoia having emerged as a key risk factor, pointing to significant worth in reducing this aspect in individuals with high positive schizotypy. Reduced paranoia in the general population following brief online mindfulness training has been previously reported. This study investigated the feasibility of a 40-day online mindfulness-based intervention (MBI) (n = 12) in the individuals with high positive schizotypy characterized by high suspiciousness/paranoia and to estimate its effect on paranoia as compared with an active control condition using reflective journaling (n = 12). The outcome measures were self-reported trait and VR-induced state paranoia, completed at baseline, after 10 days and post-intervention. The feasibility criteria included retention, adherence, engagement, and acceptability. There was 100% retention, excellent adherence to content and engagement, with an average MBI session completion rate of 91%. Acceptability, indexed by a self-rated motivation to continue practice post-intervention, was also high. No MBI effect on trait paranoia was observed; however, the MBI group showed a reduction in the VR-induced state paranoia with a medium-to-large effect (d = 0.63). The findings support conducting larger-scale randomized controlled trials to evaluate the effects of online MBIs on reducing suspiciousness/paranoia to mitigate psychosis risk in individuals with high positive schizotypy. Clinical Trial Registration:https://www.isrctn.com/, identifier ISRCTN78697391.

Investigation of Siblings of Patients Diagnosed with Substance-Induced Psychotic Disorder in terms of Cognitive Functions and Clinical High-Risk State for Psychosis

OBJECTIVE

This study aimed to investigate the influence of familial predisposition on substance-induced psychosis among healthy siblings of patients diagnosed with substance-induced psychotic disorder, who themselves lack any family history of psychotic disorders. Additionally, the study aimed to explore clinical high-risk states for psychosis, schizotypal features, and neurocognitive functions in comparison to a healthy control group.

METHOD

The study compared healthy siblings of 41 patients diagnosed with substance-induced psychotic disorder with 41 healthy volunteers without a family history of psychotic disorders, matching age, gender, and education. Sociodemographic and clinical characteristics of participants were obtained using data collection forms. The Comprehensive Assessment of At-Risk Mental States (CAARMS) and the Structured Interview for Schizotypy-Revised Form (SIS-R) scales were utilized to assess clinical high risk for psychosis. Neurocognitive functions were evaluated with digit span test (DST), trail making test part A-B (TMT), verbal fluency test (VFT), and Stroop test (ST).

RESULTS

Analysis using the CAARMS scale revealed that 39% of siblings and 7.3% of the control group were at clinically high risk for psychosis, indicating a significant difference in rates of psychotic vulnerability. Comparison between siblings and the control group showed significant differences in mean SIS-R subscale scores, including social behavior, hypersensitivity, referential thinking, suspiciousness, illusions, and overall oddness, as well as in mean neurocognitive function scores, including errors in TMT-A, TMT-B, and VFT out-of-category errors, with siblings exhibiting poorer performance.

CONCLUSION

Our study suggests that healthy siblings of patients with substance-induced psychosis exhibit more schizotypal features and have a higher risk of developing psychosis compared to healthy controls. Additionally, siblings demonstrate greater impairment in attention, response inhibition, and executive functions compared to healthy controls, indicating the potential role of genetic predisposition in the development of substance-induced psychotic disorder.

Diagnosing schizophrenia using deep learning: Novel interpretation approaches and multi-site validation

Schizophrenia is a profound and enduring mental disorder that imposes significant negative impacts on individuals, their families, and society at large. The development of more accurate and objective diagnostic tools for schizophrenia can be expedited through the employment of deep learning (DL), that excels at deciphering complex hierarchical non-linear patterns. However, the limited interpretability of deep learning has eroded confidence in the model and restricted its clinical utility. At the same time, if the data source is only derived from a single center, the model's generalizability is difficult to test. To enhance the model's reliability and applicability, leave-one-center-out validation with a large and diverse sample from multiple centers is crucial. In this study, we utilized Nine different global centers to train and test the 3D Resnet model's generalizability, resulting in an 82% classification performance (area under the curve) on all datasets sourced from different countries, employing a leave-one-center-out-validation approach. Per our approximation of the feature significance of each region on the atlas, we identified marked differences in the thalamus, pallidum, and inferior frontal gyrus between individuals with schizophrenia and healthy controls, lending credence to prior research findings. At the same time, in order to translate the model's output into clinically applicable insights, the SHapley Additive exPlanations (SHAP) permutation explainer method with an anatomical atlas have been refined, thereby offering precise neuroanatomical and functional interpretations of different brain regions.

Childhood trauma associated with psychotic-like experiences among people living with HIV: The chain mediation effect of stigma and resilience

BACKGROUND

Previous research established the associations between childhood trauma and psychosis, but the effects of childhood trauma on psychotic-like experiences (PLEs) among people living with HIV (PLWH) and the potential mediation mechanisms in these associations remain unclear.

OBJECTIVE

This study aimed to investigate the effects of childhood trauma on PLEs, as well as the chain mediation roles of stigma and resilience in this relationship. Furthermore, we explored whether the aforementioned associations differed when hallucinatory experiences (HEs) and delusional experiences (DEs) were separately modeled.

PARTICIPANTS AND SETTING

The sample included 333 outpatients participants (95.2 % males, Mage = 28.24 ± 7.12) living with HIV recruited from Hunan Province, China; and data were collected with a cross-sectional survey.

METHOD

The hypothesized chain mediation models were examined using SPSS PROCESS macro 3.3 software.

RESULTS

Various influencing mechanisms of childhood trauma on HEs and DEs were examined in this study. Our results showed that, (a) childhood trauma directly exerted negative effect on HEs, while the chain mediation effect of stigma and resilience were not statistically significant. Conversely, (b) childhood trauma exerted no direct influence on DEs but rather through the chain mediation effect of stigma and resilience.

CONCLUSIONS

The identification of two different routes between that childhood trauma can have on HEs and DEs highlighted the importance of tailored prevention and intervention among PLWH with a history of childhood trauma.

Examining the Most Important Risk Factors for Predicting Youth Persistent and Distressing Psychotic-Like Experiences

BACKGROUND

Persistence and distress distinguish more clinically significant psychotic-like experiences (PLEs) from those that are less likely to be associated with impairment and/or need for care. Identifying risk factors that identify clinically relevant PLEs early in development is important for improving our understanding of the etiopathogenesis of these experiences. Machine learning analyses were used to examine the most important baseline factors distinguishing persistent distressing PLEs.

METHODS

Using Adolescent Brain Cognitive Development (ABCD) Study data on PLEs from 3 time points (ages 9-13 years), we created the following groups: individuals with persistent distressing PLEs (n = 305), individuals with transient distressing PLEs (n = 374), and individuals with low-level PLEs demographically matched to either the persistent distressing PLEs group (n = 305) or the transient distressing PLEs group (n = 374). Random forest classification models were trained to distinguish persistent distressing PLEs from low-level PLEs, transient distressing PLEs from low-level PLEs, and persistent distressing PLEs from transient distressing PLEs. Models were trained using identified baseline predictors as input features (i.e., cognitive, neural [cortical thickness, resting-state functional connectivity], developmental milestone delays, internalizing symptoms, adverse childhood experiences).

RESULTS

The model distinguishing persistent distressing PLEs from low-level PLEs showed the highest accuracy (test sample accuracy = 69.33%; 95% CI, 61.29%-76.59%). The most important predictors included internalizing symptoms, adverse childhood experiences, and cognitive functioning. Models for distinguishing persistent PLEs from transient distressing PLEs generally performed poorly.

CONCLUSIONS

Model performance metrics indicated that while most important factors overlapped across models (e.g., internalizing symptoms), adverse childhood experiences were especially important for predicting persistent distressing PLEs. Machine learning analyses proved useful for distinguishing the most clinically relevant group from the least clinically relevant group but showed limited ability to distinguish among clinically relevant groups that differed in PLE persistence.

Bidirectional associations between short sleep duration, insomnia symptoms, and psychotic-like experiences in adolescents

This study investigates the prospective associations between short sleep duration, insomnia symptoms, and psychotic-like experiences (PLEs) in a large sample of Chinese adolescents. This study utilized a three-timepoint repeated cross-sectional survey with two nested longitudinal subsamples. A total of 17,722 adolescents were assessed at baseline (April 21 to May 12, 2021) and six months later (December 17 to 26, 2021). Out of these, 15,694 adolescents provided complete responses to the questions at baseline and one year later (May 17 - June 6, 2022). A self-administered questionnaire was used to measure sample characteristics (at baseline), sleep duration, insomnia symptoms, and PLEs (at each assessment), and negative life events (at two follow-ups). Baseline short sleep duration and insomnia symptoms predicted frequent PLEs at both follow-up assessments. Additionally, baseline frequent PLEs also predicted insomnia symptoms at six months and one year later. However, when controlling for confounders, PLEs at baseline only predicted short sleep duration at six months, and not at one year. This study reveals bidirectional prospective relationships between short sleep duration, insomnia symptoms, and PLEs, even after controlling for covariates. Therefore, it is crucial to assess both sleep patterns and PLEs in order to promote optimal sleep and mental health among adolescents.

Social influences on the relationship between dissociation and psychotic-like experiences

BACKGROUND

Shame is experienced as a threat to social self, and so activates threat-protective responses. There is evidence that shame has trauma-like characteristics, suggesting it can be understood within the same conceptual framework as trauma and dissociation. Evidence for causal links among trauma, dissociation, and psychosis thus warrant the investigation of how shame may influence causal mechanisms for psychosis symptoms.

METHODS

This study tested the interaction between dissociation and shame, specifically external shame (feeling shamed by others), in predicting psychotic-like experiences (PLEs) six months later in a general population sample (N = 314). It also tested if social safeness moderates these effects. A longitudinal, online questionnaire design tested a moderation model (dissociation-shame) and a moderated moderation model (adding social safeness), using multiple regressions with bootstrap procedures.

RESULTS

Although there was no direct effect of dissociation on PLEs six months later, there was a significant interaction effect with shame, controlling for PLEs at baseline. There were complex patterns in the directions of effects: For high-shame-scorers, higher dissociation predicted higher PLE scores, but for low-shame-scorers, higher dissociation predicted lower PLE scores. Social safeness was found to significantly moderate these interaction effects, which were unexpectedly more pronounced in the context of higher social safeness.

CONCLUSIONS

The results demonstrate evidence for an interaction between dissociation and shame on its impact on PLEs, which manifests particularly for those experiencing higher social safeness. This suggests a potential role of social mechanisms in both the etiology and treatment of psychosis, which warrants further testing in clinical populations.

Hallucination Proneness Alters Sensory Feedback Processing in Self-voice Production

BACKGROUND

Sensory suppression occurs when hearing one's self-generated voice, as opposed to passively listening to one's own voice. Quality changes in sensory feedback to the self-generated voice can increase attentional control. These changes affect the self-other voice distinction and might lead to hearing voices in the absence of an external source (ie, auditory verbal hallucinations). However, it is unclear how changes in sensory feedback processing and attention allocation interact and how this interaction might relate to hallucination proneness (HP).

STUDY DESIGN

Participants varying in HP self-generated (via a button-press) and passively listened to their voice that varied in emotional quality and certainty of recognition-100% neutral, 60%-40% neutral-angry, 50%-50% neutral-angry, 40%-60% neutral-angry, 100% angry, during electroencephalography (EEG) recordings.

STUDY RESULTS

The N1 auditory evoked potential was more suppressed for self-generated than externally generated voices. Increased HP was associated with (1) an increased N1 response to the self- compared with externally generated voices, (2) a reduced N1 response for angry compared with neutral voices, and (3) a reduced N2 response to unexpected voice quality in sensory feedback (60%-40% neutral-angry) compared with neutral voices.

CONCLUSIONS

The current study highlights an association between increased HP and systematic changes in the emotional quality and certainty in sensory feedback processing (N1) and attentional control (N2) in self-voice production in a nonclinical population. Considering that voice hearers also display these changes, these findings support the continuum hypothesis.

Precision psychiatry: predicting predictability

Precision psychiatry is an emerging field that aims to provide individualized approaches to mental health care. An important strategy to achieve this precision is to reduce uncertainty about prognosis and treatment response. Multivariate analysis and machine learning are used to create outcome prediction models based on clinical data such as demographics, symptom assessments, genetic information, and brain imaging. While much emphasis has been placed on technical innovation, the complex and varied nature of mental health presents significant challenges to the successful implementation of these models. From this perspective, I review ten challenges in the field of precision psychiatry, including the need for studies on real-world populations and realistic clinical outcome definitions, and consideration of treatment-related factors such as placebo effects and non-adherence to prescriptions. Fairness, prospective validation in comparison to current practice and implementation studies of prediction models are other key issues that are currently understudied. A shift is proposed from retrospective studies based on linear and static concepts of disease towards prospective research that considers the importance of contextual factors and the dynamic and complex nature of mental health.

Montreal Cognitive Assessment (MoCA) as a screening tool for cognitive impairment in early stages of psychosis

Background

Cognitive alterations have been reported in early stages of psychosis including people with First Episode Psychosis (FEP), Clinical High-Risk Mental State (CHR), and Psychotic-Like Experience (PLE). This study aimed to compare the cognitive function in early stages of psychosis using the Montreal Cognitive Assessment (MoCA), a low-cost and brief assessment tool of cognitive functions.

Methods

A total of 154 individuals, including 35 with FEP, 38 CHR, 44 PLE, and 37 healthy controls (HC), were evaluated with the MoCA in Santiago, Chile. We calculated the mean total score of the MoCA and the standard deviation of the mean. Groups were assessed for a trend to lower scores in a pre-determined sequence (HC > PLE > CHR > FEP) using the Jonckheere-Terpstra test (TJT).

Results

The mean total MoCA scores were 24.8 ± 3.3 in FEP, 26.4 ± 2.4 in CHR, 26.4 ± 2.3 in PLE, and 27.2 ± 1.8 in HC. The analyses revealed a significant trend (p < 0.05) toward lower MoCA individual domain scores and MoCA total scores in the following order: HC > PLE > CHR > FEP. The mean total scores of all groups were above the cut-off for cognitive impairment (22 points).

Conclusions

The MoCA describes lower scores in cognition across early stages of psychosis and may be a useful low-cost assessment instrument in early intervention centers of poorly resourced settings.

Variation of subclinical psychosis across 16 sites in Europe and Brazil: findings from the multi-national EU-GEI study

BACKGROUND

Incidence of first-episode psychosis (FEP) varies substantially across geographic regions. Phenotypes of subclinical psychosis (SP), such as psychotic-like experiences (PLEs) and schizotypy, present several similarities with psychosis. We aimed to examine whether SP measures varied across different sites and whether this variation was comparable with FEP incidence within the same areas. We further examined contribution of environmental and genetic factors to SP.

METHODS

We used data from 1497 controls recruited in 16 different sites across 6 countries. Factor scores for several psychopathological dimensions of schizotypy and PLEs were obtained using multidimensional item response theory models. Variation of these scores was assessed using multi-level regression analysis to estimate individual and between-sites variance adjusting for age, sex, education, migrant, employment and relational status, childhood adversity, and cannabis use. In the final model we added local FEP incidence as a second-level variable. Association with genetic liability was examined separately.

RESULTS

Schizotypy showed a large between-sites variation with up to 15% of variance attributable to site-level characteristics. Adding local FEP incidence to the model considerably reduced the between-sites unexplained schizotypy variance. PLEs did not show as much variation. Overall, SP was associated with younger age, migrant, unmarried, unemployed and less educated individuals, cannabis use, and childhood adversity. Both phenotypes were associated with genetic liability to schizophrenia.

CONCLUSIONS

Schizotypy showed substantial between-sites variation, being more represented in areas where FEP incidence is higher. This supports the hypothesis that shared contextual factors shape the between-sites variation of psychosis across the spectrum.

Children's early signs and developmental trajectories of psychotic-like experiences

INTRODUCTION

Children who experience persistent psychotic-like experiences (PLEs) are at a higher risk of developing psychotic disorder later in life. The developmental trajectories of PLEs are influenced by various factors. Therefore, it is important to identify early characteristics that can distinguish and predict between different developmental trajectories of PLEs.

METHODS

Using PLEs scores from the Adolescent Brain Cognitive Development (ABCD) data across three waves, we categorized participants into five distinct PLEs trajectories groups: persistent group (n = 47), remitting group (n = 185), increasing group (n = 117), remittent group (n = 21), and no PLEs group (n = 4,476). We utilized linear mixed-effect models and generalized linear mixed-effect models to examine the differences in baseline characteristics, including psychological and behavioral problems, suicidality, trauma experiences, developmental milestones, cognitive function, physical health, family income, family history of mental illness, and brain structureamong these PLEs trajectory groups.

RESULTS

We found that psychological and behavioral problems (such as DSM-oriented scales/externalizing/ADHD/social/attention/thought problems) assessed by the Child Behavior Checklist (CBCL) were associated with all PLEs groups. The persistent PLEs group had greater ADHD/social/thought problems and suicidal behavior compared to the remitting PLEs group. Comparing with the no PLEs group, poor cognitive function, abnormal brain structure (such as temporal lobe and supramarginal gyrus), more trauma experiences, and lower family income were found in only one of the PLEs groups, but not all PLEs groups.

CONCLUSION

The development of PLEs is accompanied by changes in many domains, implying a dynamic and complex developmental process. Given that psychological and behavioral problems can predict the emergence of PLEs at any time and can be regarded as risk factors for persistent PLEs, thereby enabling early precisely interventions, it is important to place greater emphasis on assessing psychological and behavioral problems.

Does insecure attachment lead to psychosis via dissociation? A systematic review of the literature

PURPOSE

Insecure attachment may constitute a vulnerability factor for psychosis, and dissociation may be a key mechanism in the development of auditory hallucinations specifically. While there is good evidence for the role of these processes in isolation, it is unclear whether dissociation accounts for the association between insecure attachment and psychosis. This systematic review takes a theory-driven approach to examine proposed causal relationships across the clinical and nonclinical literature.

METHODS

We searched five databases (PubMeD, Web of Science, PsycINFO, CINAHL and ETHOS) for published and unpublished research examining attachment, dissociation and psychosis. Two independent reviewers extracted the data and assessed the quality of all included studies.

RESULTS

We identified 242 potential articles and included 13 in the final review (2096 participants). We found that (1) disorganised attachment was consistently associated with dissociation and inconsistently associated with voices and paranoia, (2) dissociation was associated with voices and paranoia, and these links were stronger in clinical samples, and (3) dissociation played a role in the impact of insecure attachment on voice hearing and paranoia in clinical groups.

CONCLUSIONS

This is the first review to synthesise the research examining attachment, dissociation, and psychosis. The evidence is consistent with proposed causal hypotheses and raises conceptual and measurement issues, for example, the need to clarify the relative contributions of different insecure attachment styles, and utilise behavioural/observational measures to strengthen study designs. Most importantly, we need experimental and longitudinal studies to confirm causal links and targets for treatment.

The temporal association between social isolation, distress, and psychotic experiences in individuals at clinical high-risk for psychosis

BACKGROUND

Psychotic experiences (PEs) and social isolation (SI) seem related during early stages of psychosis, but the temporal dynamics between the two are not clear. Literature so far suggests a self-perpetuating cycle wherein momentary increases in PEs lead to social withdrawal, which, subsequently, triggers PEs at a next point in time, especially when SI is associated with increased distress. The current study investigated the daily-life temporal associations between SI and PEs, as well as the role of SI-related and general affective distress in individuals at clinical high risk (CHR) for psychosis.

METHODS

We used experience sampling methodology in a sample of 137 CHR participants. We analyzed the association between SI, PEs, and distress using time-lagged linear mixed-effects models.

RESULTS

SI did not predict next-moment fluctuations in PEs, or vice versa. Furthermore, although SI-related distress was not predictive of subsequent PEs, general affective distress during SI was a robust predictor of next-moment PEs.

CONCLUSIONS

Our results suggest that SI and PEs are not directly related on a moment-to-moment level, but a negative emotional state when alone does contribute to the risk of PEs. These findings highlight the role of affective wellbeing during early-stage psychosis development.

Psychometric properties of the Spanish version of the measure of insight into cognition-self-report in psychosis-risk and non-clinical Mexican young adults

AIM

Cognitive disturbances typically precede the onset of overt psychotic symptoms and represent a neurobiological marker for psychosis risk that is also associated with poor functional outcomes. The Measure of Insight into Cognition-Self Report (MIC-SR) is a widely used 12-item questionnaire that assesses the perceived frequency of cognitive impairment in the domains of executing functioning, attention, and memory. However, the MIC-SR is not available in Spanish, one of the most widely spoken languages worldwide. The present study aimed to provide a Spanish version of the MIC-SR and examine its psychometric properties in psychosis-risk and non-clinical Mexican young adults.

METHODS

The sample comprised 621 participants who completed a battery of self-report measures via an online survey. Of the participants, 478 were non-clinical, and 143 met the screening criteria for a clinical high-risk for psychosis (CHR-positive).

RESULTS

Confirmatory Factor Analyses supported a one-factor model, consistent with the findings for the original MIC-SR. The results showed adequate fit indices for the general model and the independent models for both groups, with high Cronbach's alpha coefficients. Furthermore, the CHR-positive group showed more frequent subjective cognitive problems on each of the 12 items, higher total scores, and higher average frequency than the non-clinical group.

CONCLUSION

To our knowledge, this is the first translation of the MIC-SR into Spanish. Using the MIC-SR at the CHR stage may contribute to our understanding of cognitive processes associated with the onset of a psychotic disorder and provide valuable information in the context of detection and early intervention efforts.

Perceived school bullying and psychotic-like experiences in sexual minority adolescents: the mediating and moderating roles of resilience

AIMS

This two-wave, longitudinal study aimed to examine the potential moderating and mediating effects of resilience on the association between perceived school bullying and psychotic-like experiences among Chinese sexual minority adolescents.

METHODS

A total of 4192 senior high students were included and 984 (23.5%) of them were identified as a sexual minority (mean age = 16.68 years, SD = 0.71). Participants completed two online surveys during April 21 to May 12, 2021 and December 17 to 26, 2021, respectively, as well as completed self-report measures of sample characteristics, perceived school bullying, resilience, and psychotic-like experiences (including two dimensions: delusional experiences and hallucinatory experiences).

RESULTS

Perceived school bullying and resilience were associated with psychotic-like experiences in sexual minority adolescents. Resilience mediated the relationship between perceived school bullying and subsequent psychotic-like experiences (b = 0.03, 95% CI = 0.01 ~ 0.04)/ delusional experiences (b = 0.03, 95% CI = 0.01 ~ 0.04)/ hallucinatory experiences (b = 0.02, 95% CI = 0.01 ~ 0.03). Additionally, resilience only moderated the associations of perceived school bullying with hallucinatory experiences (b = -0.06, 95% CI = -0.12 ~ -0.01).

CONCLUSIONS

These findings indicated that resilience plays a crucial role in mediating or moderating the relationship between perceived school bullying and psychotic-like experiences. Assessing and reducing school bullying, as well as promoting resilience, may have important clinical implications for reducing the risk of psychotic-like experiences in sexual minority adolescents.

Developmental changes in the endorsement of psychotic-like experiences from middle childhood through young adulthood

BACKGROUND

Children tend to endorse psychotic-like experiences (PLEs) at higher rates than adults, although little is known about how specific symptom endorsement changes across the span of development. Here we take an observational approach to examine trends in PLE endorsement by age in two non-clinical samples: one of school-aged children and another of late adolescents and early adults.

METHODS

Prodromal Questionnaire-Brief (child and adult versions) responses were investigated in individuals ages 9-13 (n = 11865) and 16-24 (n = 3209) from the Adolescent Brain and Cognitive Development Study (ABCD) and the Multisite Assessment of Psychosis-risk Study (MAP), respectively. Item-level endorsement and distressing item frequencies were examined by age throughout both cohorts.

RESULTS

Unusual perceptual experiences were generally endorsed more heavily in childhood, while other PLEs were endorsed in adolescents and adults up to 4.8 times more frequently than in children. Additionally, certain experiences were endorsed by as many as 73 percent of the older sample.

CONCLUSIONS

Considerations for the measurement of PLEs in childhood and adolescence are underscored. Findings from these two samples provide a window into the course of these PLEs and may serve as a scaffold for future research investigating normative versus risk-related experiences during development.

A Developmental Perspective on Early and Current Motor Abnormalities and Psychotic-Like Symptoms

BACKGROUND AND HYPOTHESIS

Psychotic-like experiences (PLEs) are prevalent in the general population and, because they represent a lower end of the psychosis vulnerability spectrum, may be useful in informing mechanistic understanding. Although it is well-understood that motor signs characterize formal psychotic disorders, the developmental trajectory of these features and their relationships with PLEs are less well-understood.

STUDY DESIGN

Data from 7559 adolescents and young adults (age 11-21) in the Philadelphia Neurodevelopmental Cohort were used to investigate whether early-life milestone-attainment delays relate to current adolescent sensorimotor functioning and positive and negative PLEs. Current sensorimotor functioning was assessed using the Computerized Finger Tapping task (assessing motor slowing) and Mouse Practice task (assessing sensorimotor planning).

STUDY RESULTS

Early developmental abnormalities were related to current adolescent-aged motor slowing (t(7415.3) = -7.74, corrected-P < .001) and impaired sensorimotor planning (t(7502.5) = 5.57, corrected-P < .001). There was a significant interaction between developmental delays and current sensorimotor functioning on positive and negative PLEs (t = 1.67-4.51), such that individuals with early developmental delays had a stronger positive relationship between sensorimotor dysfunction and PLEs. Importantly, interaction models were significantly better at explaining current PLEs than those treating early and current sensorimotor dysfunction independently (χ2 = 4.89-20.34).

CONCLUSIONS

These findings suggest a relationship between early developmental delays and current sensorimotor functioning in psychosis proneness and inform an understanding of heterotypic continuity as well as a neurodevelopmental perspective of motor circuits. Furthermore, results indicate that motor signs are a clear factor in the psychosis continuum, suggesting that they may represent a core feature of psychosis vulnerability.

Distal and proximal risk factors of problematic cannabis use associated with psychotic-like experiences

BACKGROUND

Problematic cannabis use is associated with endorsement of psychotic-like experiences (PLEs) in non-clinical samples. However, little is known in regard to predictors of this relationship, which may be relevant to prevention and intervention. In the present research, we investigate impulsivity and cannabis use motives as potential distal and proximal risk factors for PLEs using conditional process analysis.

METHODS

Using an online cross-sectional survey of N = 300 students, we assessed endorsement of PLEs using the Community Assessment of Psychic Experiences (CAPE), problematic cannabis use with the Cannabis Use Disorder Identification Test (CUDIT-R), motivations for using cannabis with the Substance Use Motives Measure, and impulsivity using the Urgency and Premeditation, Perseverance, Sensation Seeking, Positive Urgency Impulsive Behaviour Scale (UPPS-P).

RESULTS

All three subscales on the CAPE were associated with significantly higher scores on the CUDIT-R. Before and after covarying for sex, we found that higher CUDIT-R scores mediated the relations between lack of perseverance and negative urgency impulsivity with higher PLE symptoms. Furthermore, the indirect effect of cannabis use on the relationship between lack of perseverance and high negative PLE symptoms was only significant at high and moderate levels of depression-coping, but not at low depression-coping motives.

CONCLUSION

Impulsivity and depression-coping motives may be distal and proximal psychological risk factors for negative PLEs in the context of problematic cannabis use. Our findings are in line with the broader substance use and mental health literature and may be informative for cannabis use treatment targets.

Ethnoracial Risk Variation Across the Psychosis Continuum in the US: A Systematic Review and Meta-Analysis

Importance

Studies suggest a higher risk of schizophrenia diagnoses in Black vs White Americans, yet a systematic investigation of disparities that include other ethnoracial groups and multiple outcomes on the psychosis continuum is lacking.

Objective

To identify ethnoracial risk variation in the US across 3 psychosis continuum outcomes (ie, schizophrenia and other psychotic disorders, clinical high risk for psychosis [CHR-P], and psychotic symptoms [PSs] and psychotic experiences [PEs]).

Data Sources

PubMed, PsycINFO and Embase were searched up to December 2022.

Study Selection

Observational studies on ethnoracial differences in risk of 3 psychosis outcomes.

Data Extraction and Synthesis

Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed. Using a random-effects model, estimates for ethnoracial differences in schizophrenia and PSs/PEs were pooled and moderation by sampling and setting was determined, along with the assessment of heterogeneity and risk of bias.

Main Outcomes and Measures

Risk of schizophrenia and other psychotic disorder, CHR-P, and conversion to psychosis among CHR-P and PSs/PEs.

Results

Of 64 studies in the systematic review, 47 were included in the meta-analysis comprising 54 929 people with schizophrenia and 223 097 with data on PSs/PEs. Compared with White individuals, Black individuals had increased risk of schizophrenia (pooled odds ratio [OR], 2.07; 95% CI, 1.64-2.61) and PSs/PEs (pooled standardized mean difference [SMD], 0.10; 95% CI, 0.03-0.16), Latinx individuals had higher risk of PSs/PEs (pooled SMD, 0.15; 95% CI, 0.08-0.22), and individuals classified as other ethnoracial group were at significantly higher risk of schizophrenia than White individuals (pooled OR, 1.81; 95% CI, 1.31-2.50). The results regarding CHR-P studies were mixed and inconsistent. Sensitivity analyses showed elevated odds of schizophrenia in Asian individuals in inpatient settings (pooled OR, 1.84; 95% CI, 1.19-2.84) and increased risk of PEs among Asian compared with White individuals, specifically in college samples (pooled SMD, 0.16; 95% CI, 0.02-0.29). Heterogeneity across studies was high, and there was substantial risk of bias in most studies.

Conclusions and Relevance

Findings of this systematic review and meta-analysis revealed widespread ethnoracial risk variation across multiple psychosis outcomes. In addition to diagnostic, measurement, and hospital bias, systemic influences such as structural racism should be considered as drivers of ethnoracial disparities in outcomes across the psychosis continuum in the US.

Associations of conservatism and jumping to conclusions biases with aberrant salience and default mode network

AIM

While conservatism bias refers to the human need for more evidence for decision-making than rational thinking expects, the jumping to conclusions (JTC) bias refers to the need for less evidence among individuals with schizophrenia/delusion compared to healthy people. Although the hippocampus-midbrain-striatal aberrant salience system and the salience, default mode (DMN), and frontoparietal networks ("triple networks") are implicated in delusion/schizophrenia pathophysiology, the associations between conservatism/JTC and these systems/networks are unclear.

METHODS

Thirty-seven patients with schizophrenia and 33 healthy controls performed the beads task, with large and small numbers of bead draws to decision (DTD) indicating conservatism and JTC, respectively. We performed independent component analysis (ICA) of resting functional magnetic resonance imaging (fMRI) data. For systems/networks above, we investigated interactions between diagnosis and DTD, and main effects of DTD. We similarly applied ICA to structural and diffusion MRI to explore the associations between DTD and gray/white matter.

RESULTS

We identified a significant main effect of DTD with functional connectivity between the striatum and DMN, which was negatively correlated with delusion severity in patients, indicating that the greater the anti-correlation between these networks, the stronger the JTC and delusion. We further observed the main effects of DTD on a gray matter network resembling the DMN, and a white matter network connecting the functional and gray matter networks (all P < 0.05, family-wise error [FWE] correction). Function and gray/white matter showed no significant interactions.

CONCLUSION

Our results support the novel association of conservatism and JTC biases with aberrant salience and default brain mode.

Neurocognition and brain functional connectivity in a non-clinical population-based sample with psychotic experiences

We characterized the neurocognitive profile of communed-based individuals and unaffected siblings of patients with psychosis from Brazil reporting psychotic experiences (PEs). We also analyzed associations between PEs and the intra and inter-functional connectivity (FC) in the Default Mode Network (DMN), the Fronto-Parietal Network (FPN) and the Salience Network (SN) measured by functional magnetic resonance imaging. The combined sample of communed-based individuals and unaffected siblings of patients with psychosis comprised 417 (neurocognition) and 85 (FC) volunteers who were divided as having low (<75th percentile) and high (≥75th percentile) PEs (positive, negative, and depressive dimensions) assessed by the Community Assessment of Psychic Experiences. The neurocognitive profile and the estimated current brief intellectual quotient (IQ) were assessed using the digit symbol (processing speed), arithmetic (working memory), block design (visual learning) and information (verbal learning) subtests of Wechsler Adult Intelligence Scale-third edition. Logistic regression models were performed for neurocognitive analysis. For neuroimaging, we used the CONN toolbox to assess FC between the specified regions, and ROI-to-ROI analysis. In the combined sample, high PEs (all dimensions) were related to lower processing speed performance. High negative PEs were related to poor visual learning performance and lower IQ, while high depressive PEs were associated with poor working memory performance. Those with high negative PEs presented FPN hypoconnectivity between the right and left lateral prefrontal cortex. There were no associations between PEs and the DMN and SN FC. Brazilian individuals with high PEs showed neurocognitive impairments like those living in wealthier countries. Hypoconnectivity in the FPN in a community sample with high PEs is coherent with the hypothesis of functional dysconnectivity in schizophrenia.

Forensic aspects of dissociative positive symptoms in trauma-related disorders and borderline personality disorder

A psychotically motivated act or an act committed under impaired insight and control of action in the midst of an acute psychosis is the standard for lack of criminal responsibility. There is now increasing evidence that positive symptoms, particularly in the form of hallucinations and delusions, in trauma-related disorders and borderline personality disorder (BPD) are comparable to positive symptoms in psychotic disorders, posing a challenge for differential diagnosis and forensic assessment of the relevance of positive symptoms to insight and self-control. Due to the indistinguishability of the phenomena, there is both a risk of misdiagnosis of a psychotic disorder and also trivialization with the use of pseudo-hallucinations or quasi-psychotic labels. Essential phenomenological differences that may be helpful in forensic assessments are the usually preserved reality testing in trauma-related disorders and BPD, as well as differences in psychopathological symptom constellations. Because of these differences relevant to forensic assessments, it seems useful to distinguish trauma-related disorders and BPD with positive symptoms from psychotic disorders.

Response to psychotic experiences: Impact of personality traits on perceived levels of distress

BACKGROUND

This study examined the influence of personality traits on (subclinical) positive symptom distress in patients with a psychotic disorder, their unaffected siblings and healthy controls.

METHODS

Data were obtained from the Genetic Risk and Outcome of Psychosis study (GROUP), a Dutch longitudinal multicenter cohort study. Data from 140 patients, 216 unaffected siblings and 102 healthy controls was available for baseline levels of Five Factor Model personality traits and frequency and distress due to psychotic experiences three years later, assessed with the Community Assessment of Psychic Experience questionnaire. Main effects of all five personality traits on symptom distress were investigated as well as moderating effects of Neuroticism, Extraversion and Openness on positive symptom frequency and positive symptom distress. Age, gender, symptom frequency and IQ were controlled for.

RESULTS

In both patients and siblings, the observed main effects of Neuroticism and Openness on (subclinical) positive symptom distress three years later either lost significance or had a very small effect size when controlling for covariates, mainly due to the correction for the effect of positive symptoms on personality traits at baseline. In both groups, levels of Openness at baseline moderated the association between positive symptom frequency and positive symptom distress three years later, in the direction that higher levels of Openness were associated with weaker associations between positive symptom frequency and - distress, even when covariates were controlled for.

DISCUSSION

The level of Openness to Experiences influences the perceived distress from (subclinical) positive symptoms in both patients and siblings.

Moderating and mediating effects of resilience between childhood trauma and psychotic-like experiences among college students

BACKGROUND

Extensive literature revealed that childhood trauma serves as a significant risk factor for developing psychotic-like experiences (PLEs) among the general population. Resilience has been regarded as a protective factor against PLEs. However, it remains unclear what role resilience plays in the relationship between childhood trauma and PLEs.

METHODS

A total of 4302 college students completed the web-based survey in January 2021. Participants completed self-report measures of sample characteristics variables, childhood trauma, and PLEs. Moderation and mediation analyses were adopted to examine the associations linking childhood trauma, resilience, and PLEs.

RESULTS

PLEs were positively associated with childhood trauma while negatively associated with resilience. Resilience played a partially mediating role in the relationship between childhood trauma and PLEs. Additionally, resilience moderated the association of childhood trauma with PLEs.

CONCLUSIONS

These findings indicated that resilience plays a crucial role in mediating the relationship between childhood trauma and PLEs, suggesting the potential clinical implication of enhancing resilience for the prevention and intervention of PLEs among college students.

The mediating role of reflective functioning and general psychopathology in the relationship between childhood conduct disorder and adult aggression among offenders

BACKGROUND

The nature of the pathway from conduct disorder (CD) in adolescence to antisocial behavior in adulthood has been debated and the role of certain mediators remains unclear. One perspective is that CD forms part of a general psychopathology dimension, playing a central role in the developmental trajectory. Impairment in reflective functioning (RF), i.e., the capacity to understand one's own and others' mental states, may relate to CD, psychopathology, and aggression. Here, we characterized the structure of psychopathology in adult male-offenders and its role, along with RF, in mediating the relationship between CD in their adolescence and current aggression.

METHODS

A secondary analysis of pre-treatment data from 313 probation-supervised offenders was conducted, and measures of CD symptoms, general and specific psychopathology factors, RF, and aggression were evaluated through clinical interviews and questionnaires.

RESULTS

Confirmatory factor analyses indicated that a bifactor model best fitted the sample's psychopathology structure, including a general psychopathology factor (p factor) and five specific factors: internalizing, disinhibition, detachment, antagonism, and psychoticism. The structure of RF was fitted to the data using a one-factor model. According to our mediation model, CD significantly predicted the p factor, which was positively linked to RF impairments, resulting in increased aggression.

CONCLUSIONS

These findings highlight the critical role of a transdiagnostic approach provided by RF and general psychopathology in explaining the link between CD and aggression. Furthermore, they underscore the potential utility of treatments focusing on RF, such as mentalization-based treatment, in mitigating aggression in offenders with diverse psychopathologies.

Longitudinal trajectories of anterior cingulate glutamate and subclinical psychotic experiences in early adolescence: the impact of bullying victimization

Previous studies reported decreased glutamate levels in the anterior cingulate cortex (ACC) in non-treatment-resistant schizophrenia and first-episode psychosis. However, ACC glutamatergic changes in subjects at high-risk for psychosis, and the effects of commonly experienced environmental emotional/social stressors on glutamatergic function in adolescents remain unclear. In this study, adolescents recruited from the general population underwent proton magnetic resonance spectroscopy (MRS) of the pregenual ACC using a 3-Tesla scanner. We explored longitudinal data on the association of combined glutamate-glutamine (Glx) levels, measured by MRS, with subclinical psychotic experiences. Moreover, we investigated associations of bullying victimization, a risk factor for subclinical psychotic experiences, and help-seeking intentions, a coping strategy against stressors including bullying victimization, with Glx levels. Finally, path analyses were conducted to explore multivariate associations. For a contrast analysis, gamma-aminobutyric acid plus macromolecule (GABA+) levels were also analyzed. Negative associations were found between Glx levels and subclinical psychotic experiences at both Times 1 (n = 219, mean age 11.5 y) and 2 (n = 211, mean age 13.6 y), as well as for over-time changes (n = 157, mean interval 2.0 y). Moreover, effects of bullying victimization and bullying victimization × help-seeking intention interaction effects on Glx levels were found (n = 156). Specifically, bullying victimization decreased Glx levels, whereas help-seeking intention increased Glx levels only in bullied adolescents. Finally, associations among bullying victimization, help-seeking intention, Glx levels, and subclinical psychotic experiences were revealed. GABA+ analysis revealed no significant results. This is the first adolescent study to reveal longitudinal trajectories of the association between glutamatergic function and subclinical psychotic experiences and to elucidate the effect of commonly experienced environmental emotional/social stressors on glutamatergic function. Our findings may deepen the understanding of how environmental emotional/social stressors induce impaired glutamatergic neurotransmission that could be the underpinning of liability for psychotic experiences in early adolescence.

The relations of psychotic-like experiences (PLEs) and depressive symptoms and the bias of depressive symptoms during the clustering among Chinese adolescents: Findings from the network perspective

BACKGROUND

There are rare studies about the network structure of psychotic-like experiences (PLEs) and depressive symptoms among adolescents. Studies have widely acknowledged that PLEs in adolescents confer a higher risk of depressive symptoms, but the complex interactions remain inadequately understood. Our study aimed to examine the hierarchy and inter-associations of PLEs and depressive symptoms in a large adolescent sample from the network analysis perspective.

METHODS

A total of 5008 Chinese adolescents were enrolled in our sample. Community Assessment of Psychic Experiences-42 (CAPE-42) was applied to build the network. Centrality indexes were calculated to represent the significance of nodes in the network. Community detection was conducted to figure out the specific clustering of nodes. Demographic information was collected for the sub-network comparisons. Accuracy and stability of the network were also tested.

RESULTS

"Failure", "External control", and "Lack of activity" were the most central nodes. The main bridge nodes linking PLEs and depressive symptoms were "Failure", "Guilty", and "No future". Positive PLE "Odd looks" and negative PLE "Unable to terminate" are the two PLEs that were most relevant to depressive nodes. Community detection further demonstrated the bias of depressive nodes in the data-driven clustering. Comparative sub-network analysis suggested that age was the only demographic factor related to the current network.

CONCLUSION

In this study of a large adolescent sample, we first demonstrated the network structure and specific clustering preference of PLEs and depressive symptoms. Our findings may enhance the understanding of the relationship between PLE and depressive symptoms.

Representation of Voice Hearing Groups by French Mental Health Professionals

Hearing voices groups (HVGs) are an alternative way of treating acoustic-verbal hallucinations. Although they have been developing in France for the last decade, they have lagged behind their international expansion. The representations that circulate about their functioning and their effects are likely to influence the referral to these groups by mental health professionals. We created and used a questionnaire to survey mental health professionals' representations of voice hearing groups. We surveyed 79 French health professionals using a questionnaire with 19 closed items. 7 additional items allowed us to specify the professional status and familiarity of the participants with the HVGs. Professionals generally shared positive representations of HVGs but had very approximate knowledge of them. The subgroup of the most familiar professionals (N = 45) differed significantly on 7 items from the subgroup of non-familiars (N = 35). HVGs are represented as one medical offer among others, of little clinical use and indicated only for psychotic voice-hearing patients, which seems to be a misunderstanding in every case. However, our study also shows that these opinions evolve with the degree of familiarity with HVGs. Certain representations need to be corrected so that quality information can be circulated about HVGs and improve their integration into their ecosystem.

Polygenic risk scores mediating functioning outcomes through cognitive and clinical features in youth at family risk and controls

Schizophrenia and bipolar disorder exhibit substantial clinical overlap, particularly in individuals at familial high risk, who frequently present sub-threshold symptoms before the onset of illness. Severe mental disorders are highly polygenic traits, but their impact on the stages preceding the manifestation of mental disorders remains relatively unexplored. Our study aimed to examine the influence of polygenic risk scores (PRS) on sub-clinical outcomes over a 2-year period in youth at familial high risk for schizophrenia and bipolar disorder and controls. The sample included 222 children and adolescents, comprising offspring of parents with schizophrenia (n = 38), bipolar disorder (n = 80), and community controls (n = 104). We calculated PRS for psychiatric disorders, neuroticism and cognition using the PRS-CS method. Linear mixed-effects models were employed to investigate the association between PRS and cognition, symptom severity and functioning. Mediation analyses were conducted to explore whether clinical features acted as intermediaries in the impact of PRS on functioning outcomes. SZoff exhibited elevated PRS for schizophrenia. In the entire sample, PRS for depression, neuroticism, and cognitive traits showed associations with sub-clinical features. The effect of PRS for neuroticism and general intelligence on functioning outcomes were mediated by cognition and symptoms severity, respectively. This study delves into the interplay among genetics, the emergence of sub-clinical symptoms and functioning outcomes, providing novel evidence on mechanisms underpinning the continuum from sub-threshold features to the onset of mental disorders. The findings underscore the interplay of genetics, cognition, and clinical features, providing insights for personalized early interventions.

Sleep spindle activity and psychotic experiences: Examining the mediating roles of attentional performance and perceptual distortions in a daytime nap study

Decreased sleep spindle activity in individuals with psychotic disorders is well studied, but its contribution to psychotic symptom formation is not well understood. This study explored potential underlying mechanisms explaining the association between decreased sleep spindle activity and psychotic symptoms. To this end, we analysed the links between sleep spindle activity and psychotic experiences and probed for the mediating roles of attentional performance and perceptual distortions in a community sample of young adults (N = 70; 26.33 ± 4.84 years). Polysomnography was recorded during a 90-min daytime nap and duration, amplitude, and density from slow (10-13 Hz) and fast (13-16 Hz) spindles were extracted. Attentional performance was assessed via a test battery and with an antisaccadic eye movement task. Psychotic experiences (i.e., paranoid thoughts; hallucinatory experiences) and perceptual distortions (i.e., anomalous perceptions; sensory gating deficits) were assessed via self-report questionnaires. We conducted sequential mediation analyses with spindle activity as predictor, psychotic experiences as dependent variable, and attentional performance and perceptual distortions as mediators. We found reduced right central spindle amplitude to be associated with paranoid thoughts. Increased antisaccadic error rate was associated with anomalous perceptions and perceptual distortions were associated with psychotic experiences. We did not find significant mediation effects. The findings support the notion that reduced sleep spindle activity is involved in the formation of paranoid thoughts and that decreased antisaccadic performance is indicative of perceptual distortions as potential precursors for psychotic experiences. However, further research is needed to corroborate the proposed mediation hypothesis.

Do anxiety symptoms and coping motives serially mediate the association between psychotic-like experiences and cannabis-related problems in undergraduate recent cannabis users?

Many Canadian emerging adults (ages 18-25 years) use cannabis, with 60 % of past-three-month users experiencing one or more cannabis-related problems (i.e., adverse consequences of use). While psychotic-like experiences (PLEs) and cannabis problems overlap, little is known about the mechanisms explaining this link. One hypothesis is that PLEs are distressing and give rise to anxiety, with which emerging adults attempt to cope through increased cannabis use, in turn increasing their risk for cannabis-related problems. We tested a chained-mediational model to determine if anxiety and coping-with-anxiety motives for cannabis use sequentially mediated the link between PLEs and cannabis problems in emerging adult undergraduates; a conditional process model tested for moderation by sex. Emerging adult cannabis users (N = 413; mean [SD] age = 19.1 [1.5] years; 71.9 % female) from five Canadian universities provided cross-sectional, self-report survey data in fall 2021. Validated measures of PLEs, anxiety, cannabis coping-with-anxiety motives, and cannabis-related problems were administered. Path analyses supported the hypothesized chained mediational indirect effect (b = 0.027, 95 % bootstrap CI [0.012, 0.050]). No direct effect was found (p =.698), suggesting that the PLEs-to-cannabis problems association is fully explained by anxiety and cannabis coping-with-anxiety motives. Inconsistent with hypotheses, mediation did not depend on sex (95 % CIs crossed zero); therefore, anxiety and cannabis coping-with-anxiety motives explain the link between PLEs and cannabis problems in emerging adults regardless of their sex. Results highlight anxiety and cannabis coping-with-anxiety motives as potentially important intervention targets in cannabis-using emerging adults with PLEs, possibly preventing the development/worsening of cannabis-related problems.

Moral learning and positive schizotypy: Social cognitive mechanisms in psychosis- proneness

BACKGROUND

Delusional thoughts such as paranoia and conspiratorial thinking reflect beliefs in others' intentions to do harm. Given the integral role of harm evaluation in moral cognition, a better understanding of how psychosis-prone individuals process others' moral characters may provide insights into social cognitive mechanisms of these types of delusions.

METHODS

An online sample of 293 participants was drawn from the general population, using Amazon Mechanical Turk. Participants performed a moral inference task, where they predicted and judged the binary choices of two fictitious agents ("good" or "bad") to impose harm under different levels of financial incentives. An investment game involving the same agents then examined participants' trust behavior. Psychosis-proneness was measured with the Multidimensional Schizotypy Scale Brief Edition.

RESULTS

A set of multiple regressions showed that positive schizotypy was associated with a lower yet more confident pre-experimental expectation of the agent's moral character, lower prediction accuracy of the agent's harm preferences, less belief revision, and undifferentiated perception of the good and bad agents' characters. Positive schizotypy was also related to higher expectations for reciprocity in the investment game, regardless of agent characters.

CONCLUSION

Our findings suggest that inflexible beliefs associated with psychosis-proneness extend beyond negative prior expectations, also reflecting difficulties in moral learning. The resulting undifferentiated moral impressions might contribute to undue suspicion of benevolent individuals and increased gullibility to malicious ones, potentially further strengthening conspiratorial beliefs.

Sleep disturbance and suicidal ideation mediated by psychotic-like experiences in adolescents: a two-wave longitudinal study

STUDY OBJECTIVES

Sleep disturbance may cause suicidal ideation (SI). This study aimed to examine their co-occurrence rate among adolescents and investigate whether psychotic-like experiences (PLEs) mediate this association.

METHODS

A total of 17 722 Chinese adolescents were included in this two-wave longitudinal study. The baseline survey (time 1, T1) was conducted between April 21 and May 12, 2021, and the follow-up survey (time 2, T2) was implemented between December 17 and 26, 2021. At T1, participants completed questionnaires to assess their sleep disturbance, sleep duration, PLEs, SI, depressive symptoms, and sociodemographic characteristics. At T2, participants reported their PLEs, SI, and negative life events.

RESULTS

The SI prevalence decreased from 20.2% (T1) to 18.4% (T2). Participants with SI showed significantly higher prevalence of sleep disturbance and short sleep duration compared to those without SI. Baseline sleep disturbance and short sleep duration were both associated with the increased risk of SI 6 months later. These longitudinal links were mediated by PLEs, independent of baseline covariates and negative life events.

CONCLUSIONS

These findings provide a novel insight into the mechanism linking sleep problems and suicidality, and stress the significance of assessing and addressing sleep problems and PLEs for adolescent suicide prevention and intervention.

Evidence for Reduced Sensory Precision and Increased Reliance on Priors in Hallucination-Prone Individuals in a General Population Sample

BACKGROUND

There is increasing evidence that people with hallucinations overweight perceptual beliefs relative to incoming sensory evidence. Past work demonstrating prior overweighting has used simple, nonlinguistic stimuli. However, auditory hallucinations in psychosis are often complex and linguistic. There may be an interaction between the type of auditory information being processed and its perceived quality in engendering hallucinations.

STUDY DESIGN

We administered a linguistic version of the conditioned hallucinations (CH) task to an online sample of 88 general population participants. Metrics related to hallucination-proneness, hallucination severity, stimulus thresholds, and stimulus detection rates were collected. Data were used to fit parameters of a Hierarchical Gaussian Filter (HGF) model of perceptual inference to determine how latent perceptual states influenced task behavior.

STUDY RESULTS

Replicating past results, higher CH rates were observed both in those with recent hallucinatory experiences as well as participants with high hallucination-proneness; CH rates were positively correlated with increased prior weighting; and increased prior weighting was related to hallucination severity. Unlike past results, participants with recent hallucinatory experiences as well as those with higher hallucination-proneness had higher stimulus thresholds, lower sensitivity to stimuli presented at the highest threshold, and had lower response confidence, consistent with lower precision of sensory evidence.

CONCLUSIONS

We replicate the finding that increased CH rates and recent hallucinations correlate with increased prior weighting using a linguistic version of the CH task. Results support a role for reduced sensory precision in the interplay between prior weighting and hallucination-proneness.