Is early adulthood a critical developmental stage for psychosis proneness? A survey of delusional ideation in normal subjects

Longitudinal trajectories of psychotic-like experiences influence adolescent suicidal ideation: The mediating role of depressive symptoms

BACKGROUND

Psychotic-like experiences (PLEs) are strongly associated with poor mental health among adolescents. This study aims to investigate distinct longitudinal trajectories of the PLEs and their relationship to suicidal ideation (SI), as well as to evaluate the mediating effect of depressive symptoms on this link.

METHODS

A total of 7529 Chinese adolescents were surveyed on PLEs online during April 21 to May 12, 2021 (Time 1, T1), December 17 to 26, 2021 (Time 2, T2), and May 17 to June 5, 2022 (Time 3, T3). Depressive symptoms and SI were assessed at T1 and T3.

RESULTS

The prevalence of frequent PLEs across the three surveys was 13.5 %, 13.2 %, and 11.0 %, respectively. Five PLEs trajectories were identified: resistance (74.4 % of the sample), recovery (9.2 %), delayed-dysfunction (6.6 %), relapsing/remitting (7.0 %), and chronic-dysfunction (2.8 %). Adolescents in recovery, delayed-dysfunction, relapsing/remitting, and chronic-dysfunction trajectories compared with those in the resistant group were all more likely to experience SI at T3 after adjusting for a wide range of covariates. Depressive symptoms partially mediated the effects of PLEs trajectories (relative to the resistance trajectory) on SI (95 % CIs: 0.07-0.13, 0.37-0.48, and 0.28-0.41 for relapsing/remitting, delayed-dysfunction, and chronic-dysfunction trajectories, respectively).

CONCLUSIONS

PLEs are common among adolescents and have heterogeneity of change patterns. The association between PLEs trajectories and SI is partially mediated by depressive symptoms. Timely assessment and targeted interventions for specific PLEs are necessary to reduce the incidence of mental disorders.

Further Validation of the Persecutory Ideation Questionnaire in the Italian Context: Results From Classical and Modern Test Theory

The Persecutory Ideation Questionnaire (PIQ) is a valuable instrument to measure persecutory ideation. The aim of this study is to validate the scale in the Italian context and to extend the study of its psychometric properties using approaches from both classical and modern test theories. The results of the study, involving 700 individuals, confirmed the one-factor structure and the good validity and reliability of the scale. Full metric invariance and partial scalar and strict invariance were also supported across gender, age, and education level groups. Rasch analysis indicated that the 5-point response scale is well-functioning and that the PIQ is most appropriate to measure high levels of persecutory ideation. The results contribute to a better understanding of the measurement properties of the PIQ. The paper discusses the advantages and contributions of each method used to explore the measurement properties of the scale.

Complex Bodily Hallucinatory Experiences Scale (CBHES): Development, structure and psychometric properties

OBJECTIVES

Complex bodily hallucinations are not rare in psychiatric, neurological and toxicological conditions and may also be reported even in the total absence of any medical condition. Despite this, they are usually not clinically assessed independently from (and in comparison to) hallucinations in other modalities. The objective of this study was to develop a short scale assessing complex bodily hallucinations.

METHODS

Based on previous research and clinical reports, we present a new short scale for the assessment of four themes of such hallucinations, i.e., delusional parasitosis, the feeling of presence, autoscopic phenomena, and body distortions. The scale was completed by 623 participants from the general population.

RESULTS

Complex bodily hallucinations are frequent, with 96.6% of the sample reporting at least one. A Confirmatory Factor Analysis showed that the data best fit a hierarchical model in which the four independent themes are linked to a higher-order factor that we tentatively identifed as bodily self-consciousness. Each one of the four themes was reported in isolation in less than 5% of the sample, but combinations of themes were more frequent. The scale has good internal consistency, a good 3-month test-retest reliability, and good convergent validity. Furthermore, the scale has a good balance between specificity and sensitivity when the 90th percentile of the total score is used as a classification criterion.

CONCLUSION

The short scale developed has good psychometric properties and can be used both in clinical and research settings.

Ruminative thinking mediates the effects of exposure to adverse life events on psychotic-like experiences

Introduction

A growing literature has shown that exposure to adverse life events during childhood or adolescence is associated with the presence of psychotic-like experiences (PLEs), which is in turn associated with the risk of psychotic outcomes. Ruminative thinking, i.e., the tendency to dwell on particular issues or ideas, may affect the perceived aversiveness and ability to cope with adverse life events. However, the role that rumination plays in the relationship between adverse life events and the presence of PLEs remains unclear. The purpose of this study is to assess the association between adverse life events and PLEs in a longitudinal sample of young adults and adolescents, and to investigate whether this relationship is mediated by ruminative thinking.

Methods

We used a longitudinal naturalistic sample of 706 volunteers assessed at ages 18 and 22 years, within the Imagen consortium. Lifetime occurrence of adverse life events (i.e., events perceived as strongly negative by participants) was investigated using the Life Events Questionnaire. The Community Assessment of Psychic Experience (CAPE-42) served to assess the presence of PLEs, while ruminative thinking was investigated through the Ruminative Response Scale.

Results

Results showed that both frequency of PLEs and their persistence over time were associated with greater adverse life events exposure (r = 0.32, p < 0.001 and F 1 = 9.8; p < 0.001, respectively) and greater ruminative response (r = 0.66, p < 0.001 and F 1 = 94.9; p < 0.001, respectively). Mediation analyses showed that relationship between adverse life events and PLEs frequency was partially mediated by rumination (direct effect Z: 5.4, p < 0.001; indirect effect Z: 6.9, p < 0.001; total effect Z: 5.9, p < 0.001). Considering changes between the two assessment timepoints, relationship between PLEs variation between 18 and 22 years and adverse life events occurred during the same period was partially mediated by changes in rumination (direct effect Z: 2.8, p < 0.005; indirect effect Z: 4.3, p < 0.001; total effect Z: 4.3; p < 0.001).

Discussion

Overall, our findings confirm that the presence of adverse life events may increase the risk of experiencing PLEs in healthy individuals and suggest that dysfunctional coping strategies, such as ruminative thinking, may be related to psychosis proneness. Results do not disentangle whether individuals with greater risk for psychosis tend to ruminate more or whether rumination exacerbates psychosis risk.

Reduction of Psychosis Proneness in a Daycare Hospital Program for Patients with Severe Alcohol Use Disorder

OBJECTIVES

Anxiety and depressive symptoms, as well as cognitive dysfunctions, improve with abstinence in individuals with alcohol use disorders (AUD), but less is known about psychotic features. The objective of this study was to evaluate the psychosis proneness in a sample of individuals with severe AUD and potential changes after alcohol withdrawal.

METHOD

An observational study was conducted, assessing prospectively Peter's Delusional Inventory scale (PDI); anxiety and depression symptoms by MADRS and cognitive functioning by the MoCA at entry in daycare hospital (D0) and after 30 days (D30). Individuals with schizophrenia, chronic delusional disorder and bipolar disorder were excluded. Wilcoxon tests were used to evaluate the evolution between D0 and D30, and linear regressions were conducted to test the association between delta PDI and the variables that could be potential confounders.

RESULTS

Forty individuals (72% males) with a mean age of 50 ± 9 years old and AUD evolved for 15 ± 11 years were included. After one month, PDI score decreased significantly (p = .001), and several biological and clinical parameters improved significantly with abstinence or consumption reduction: GGT (p = .003), MoCA (p < .001), MADRS (p = .047).

CONCLUSION

We observed a decrease in delusional thinking along abstinence and/or consumption reduction. To our knowledge, this is the first research to study psychosis proneness evolution in patients with severe AUD. Replications are required in independent samples with larger sample size.

Impaired Sleep Mediates the Relationship Between Interpersonal Trauma and Subtypes of Delusional Ideation

BACKGROUND AND HYPOTHESIS

Trauma is a robust risk factor for delusional ideation. However, the specificity and processes underlying this relationship are unclear. Qualitatively, interpersonal traumas (i.e., trauma caused by another person) appear to have a specific relationship with delusional ideation, particularly paranoia, given the commonality of social threat. However, this has not been empirically tested and the processes by which interpersonal trauma contributes to delusional ideation remain poorly understood. Given the role of impaired sleep in both trauma and delusional ideation, it may be a critical mediator between these variables. We hypothesized that interpersonal trauma, but not non-interpersonal trauma, would be positively related to subtypes of delusional ideation, especially paranoia, and that impaired sleep would mediate these relationships.

STUDY DESIGN

In a large, transdiagnostic community sample (N = 478), an exploratory factor analysis of the Peter's Delusion Inventory identified three subtypes of delusional ideation, namely magical thinking, grandiosity, and paranoia. Three path models, one for each subtype of delusional ideation, tested whether interpersonal trauma and non-interpersonal trauma were related to subtypes of delusional ideation, and impaired sleep as a mediating variable of interpersonal trauma.

STUDY RESULTS

Paranoia and grandiosity were positively related to interpersonal trauma and unrelated to non-interpersonal trauma. Furthermore, these relationships were significantly mediated by impaired sleep, which appeared strongest for paranoia. In contrast, magical thinking was unrelated to traumatic experiences.

CONCLUSIONS

These findings support a specific relationship between interpersonal trauma and paranoia as well as grandiosity, with impaired sleep appearing as an important process by which interpersonal trauma contributes to both.

Revisiting delusion subtypes in schizophrenia based on their underlying structures

A clear understanding of the pathophysiology of schizophrenia and related spectrum disorders has been limited by clinical heterogeneity. We investigated whether relative severity and predominance of one or more delusion subtypes might yield clinically differentiable patient profiles. Patients (N = 286) with schizophrenia spectrum disorders (SSD) completed the 21-item Peters et al. Delusions Inventory (PDI-21). We performed factor analysis followed by k-means clustering to identify delusion factors and patient subtypes. Patients were further assessed via the Brief Psychiatric Rating Scale, Brief Negative Symptom Scale, Digit Symbol and Digit Substitution tasks, use of cannabis and tobacco, and stressful life events. The overall patient sample clustered into subtypes corresponding to Low-Delusion, Grandiose-Predominant, Paranoid-Predominant, and Pan-Delusion patients. Paranoid-Predominant and Pan-Delusion patients showed significantly higher burden of positive symptoms, while Low-Delusion patients showed the highest burden of negative symptoms. The Paranoia delusion factor score showed a positive association with Digit Symbol and Digit Substitution tasks in the overall sample, and the Paranoid-Predominant subtype exhibited the best performance on both tasks. Grandiose-Predominant patients showed significantly higher tobacco smoking severity than other subtypes, while Paranoid-Predominant patients were significantly more likely to have a lifetime diagnosis of Cannabis Use Disorder. We suggest that delusion self-report inventories such as the PDI-21 may be of utility in identifying sub-syndromes in SSD. From the current study, a Paranoid-Predominant form may be most distinctive, with features including less cognitive impairment and a stronger association with cannabis use.

Examining delusional ideation: Relationships with race and socioeconomic status

Race and socioeconomic status (SES) are commonly cited as risk factors for psychosis and psychotic-like experiences (PLEs). However, few studies have investigated the relationships between race and SES with specific domains of PLEs. Specifically, little work has examined the relationships between race and SES with delusional ideation, severity (preoccupation, conviction, distress), and delusional themes. Using cross-sectional, general population data (N = 727) from the Nathan Kline Institute-Rockland (NKI-Rockland) database, we investigated racial differences in delusional ideation and severity between Black and White participants, including differences in delusional themes. Then, we investigated SES's relationship with delusional thinking and the interaction between race and SES on delusional thinking. Black American participants endorsed higher delusional ideation with stronger severity than White Americans. A significant interaction between race and delusional theme revealed that Black Americans endorse significantly more delusional ideation in themes of grandiosity, religiosity, and referential-guilt. Black Americans endorse greater delusional severity in grandiose and religious ideations. Black Americans endorse stronger preoccupation and conviction - but not distress-in their referential-guilt ideation. SES was not significantly associated with delusional thinking, nor did SES moderate the significant relationships between race and delusional ideation. These results illuminate the clear racial disparity that exist in delusional ideation within a general population, which did not extend to SES in this dataset. Future work should investigate deeper into the contributory factors to these racial disparities, particularly whether they are based in psychological and/or cultural differences or are the result of assessment/measurement bias.

Psychosis screening questionnaire: Exploring its factor structure among South African adults

Background

Early detection of psychosis improves treatment outcomes, but there is limited research evaluating the validity of psychosis screening instruments, particularly in low-resourced countries.

Aim

This study aims to assess the construct validity and psychometric properties of the psychosis screening questionnaire (PSQ) in South Africa.

Setting

This study was conducted at several health centres in the Western and Eastern Cape provinces in South Africa.

Methods

The sample consisted of 2591 South African adults participating as controls in a multi-country case-control study of psychiatric genetics. Using confirmatory factor analysis and item response theory, we evaluated the psychometric properties of the PSQ.

Results

Approximately 11% of the participants endorsed at least one psychotic experience on the PSQ, and almost half of them (49%) occurred within the last 12 months. A unidimensional model demonstrated good fit (root mean square error of approximation [RMSEA] = 0.023, comparative fit index [CFI] = 0.977 and Tucker-Lewis Index [TLI] = 0.954). The mania item had the weakest association with a single latent factor (standardised factor loading = 0.14). Model fit improved after removing the mania item (RMSEA = 0.025, CFI = 0.991 and TLI = 0.972). With item response theory analysis, the PSQ provided more information at higher latent trait levels.

Conclusion

Consistent with prior literature, the PSQ demonstrated a unidimensional factor structure among South Africans. In our study, the PSQ in screening for psychosis performed better without the mania item, but future criterion validity studies are warranted.

Contribution

This study highlights that PSQ can be used to screen for early psychosis.

The Difficulties of Grandiose Delusions: Harms, Challenges, and Implications for Treatment Engagement

BACKGROUND AND HYPOTHESIS

Grandiose delusions may entail difficult responsibilities and detrimental actions for patients. Recognition of these consequences by patients may provide an avenue for engagement in treatment. Furthermore, when patients carry out actions within the delusional system ("immersion behaviors") or spend considerable time thinking about their grandiose beliefs this may contribute to the persistence of the grandiosity and further harmful consequences. We, therefore, investigated grandiose-related subjective harm, immersion behaviors, and perseverative thinking.

STUDY DESIGN

A cross-sectional study with 798 patients with psychosis (375 of whom had grandiose delusions) and 4518 nonclinical adults. Factor analyses using data from participants scoring highly on grandiosity were used to form 3 scales: subjective harm from exceptional experiences questionnaire; immersion behaviors questionnaire; and thinking about exceptional experiences questionnaire. Associations with grandiosity were tested using structural equation modeling.

STUDY RESULTS

A total of 268 (77.9%) patients with grandiose delusions identified grandiose-related harms in the past 6 months and 199 (55.1%) wanted help. Immersion behaviors and perseverative thinking were highly prevalent, and explained 39.5% and 20.4% of the variance in grandiosity, respectively. Immersion behaviors and perseverative thinking were significantly associated with subjective harm, even when severity of grandiosity was controlled. Requests for help were associated with higher levels of subjective harm, use of immersion behaviors, and perseverative thinking but not severity of grandiosity.

CONCLUSIONS

Acting on grandiose delusions, including harmful behaviors and excessive thinking about grandiose delusions, may be routes for clinicians to engage patients in treatment. This could be a starting point for targeted psychological interventions for grandiose delusions.

Ontological Adaptation in Transition to Adulthood: A Theoretical Framework for Integrating Phenomenology and Neuroscience in Psychosis Research

In this theoretical review, the neurodevelopmental model of psychotic disorders is considered within the framework of ontological development, referring to the individual-level construction of a sense of reality regarding identity and worldview. Following Erikson's theory of development, the challenge of forging a personal and social identity is a developmental process typical of late adolescence and early adulthood. Accompanying this process is a developmentally normal increase in exploratory and risk-taking behavior, which sometimes includes challenging and defying cultural norms. Although many aspects of ontological adaptation are developmentally appropriate, we argue that psychopathology such as psychosis can be rooted in an abnormal deviation of this process, in which aberrant salience accelerates the typical drive to develop a meaningful sense of identity, leading to delusion formation. By placing psychosis onset within a broader context of normal development, this model offers a humanistic approach for understanding experiences of new onset of psychotic disorders.

Effect of stressful life events on subclinical psychotic symptoms in first-degree relatives and healthy controls

Exposure to Stressful Life Events (SLEs) has been linked to psychosis. However, the combined effect of SLEs and familial risk on subclinical psychotic symptoms over time remains unknown. The objective of the present study was to investigate the effect of SLEs on the level of subclinical psychotic symptoms in individuals with and without familial vulnerability for psychosis. Data were collected from siblings of individuals diagnosed with psychotic disorder and healthy controls at baseline (N = 293) and three years later at follow-up (N = 928). We assessed self-reported and observer-rated subclinical positive, negative, and depressive psychotic symptoms. Participants reported the number of SLEs in the preceding 6 months. A multilevel multivariate regression analysis revealed a positive association between the retrospectively assessed number of SLEs and symptom levels, regardless of vulnerability status (p < .001 for all outcomes). The prospective analysis demonstrated that exposure to SLEs at baseline predicted higher levels of subclinical psychotic symptoms at follow-up. However, after controlling for the level of symptoms at baseline, these associations were no longer significant. Again, the vulnerability status did not modify these results. Nevertheless, siblings in our sample were approximating the end of the critical period for the development of psychotic disorder (mean age at baseline M = 29 and follow-up M = 34). The findings partly support the vulnerability-stress model of psychosis, yet do not confirm the role of familial risk in this association. SLEs may represent a risk factor for psychosis at a population level, thus supporting the continuity of the psychosis spectrum in terms of associated risk factors.

Empathy, Emotion Recognition, and Paranoia in the General Population

Background

Paranoia is associated with a multitude of social cognitive deficits, observed in both clinical and subclinical populations. Empathy is significantly and broadly impaired in schizophrenia, yet its relationship with subclinical paranoia is poorly understood. Furthermore, deficits in emotion recognition - a very early component of empathic processing - are present in both clinical and subclinical paranoia. Deficits in emotion recognition may therefore underlie relationships between paranoia and empathic processing. The current investigation aims to add to the literature on social cognition and paranoia by: (1) characterizing the relationship between paranoia and empathy, and (2) testing whether there is an indirect effect of emotion recognition on the relationship between empathy and paranoia.

Methods

Paranoia, empathy, and emotion recognition were assessed in a non-clinical sample of adults (n = 226) from the Nathan Kline Institute-Rockland (NKI-Rockland) dataset. Paranoia was measured using the Peters Delusions Inventory-21 (PDI-21). Empathy was measured using the Interpersonal Reactivity Index (IRI), a self-report instrument designed to assess empathy using four subscales: Personal Distress, Empathic Concern, Perspective Taking, and Fantasy. Emotion recognition was assessed using the Penn Emotion Recognition Test (ER-40). Structural equation modeling (SEM) was used to estimate relationships between paranoia, the four measures of empathy and emotion recognition.

Results

Paranoia was associated with the Fantasy subscale of the IRI, such that higher Fantasy was associated with more severe paranoia (p < 0.001). No other empathy subscales were associated with paranoia. Fantasy was also associated with the emotion recognition of fear, such that higher Fantasy was correlated with better recognition of fear (p = 0.008). Paranoia and emotion recognition were not significantly associated. The Empathic Concern subscale was negatively associated with emotion recognition, with higher empathic concern related to worse overall emotion recognition (p = 0.002). All indirect paths through emotion recognition were non-significant.

Discussion

These results suggest that imaginative perspective-taking contributes to paranoia in the general population. These data do not, however, point to robust global relationships between empathy and paranoia or to emotion recognition as an underlying mechanism. Deficits in empathy and emotion recognition observed in schizophrenia may be associated with the broader pathology of schizophrenia, and therefore not detectable with subclinical populations.

Psychotic-like experiences among 9,564 Kenyan adolescents and young adults

OBJECTIVE

To investigate the prevalence and characteristics of psychotic-like experiences (PLE) in a large cohort of Kenyan adolescents and young adults.

METHOD

The Washington Early Recognition Center Affectivity and Psychosis (WERCAP) Screen was used to the study the 12-month prevalence of PLE's among 9,564 Kenyan youths (aged 15-25 yrs), and the rates of psychosis high-risk (HR) and medium-risk (MR) cases, based on cut-off scores. Relationships with clinical, demographic and economic profiles were investigated.

RESULTS

Across all participants, 72% reported having had at least one PLE over the last year. 4.6% and 30.6% were HR and MR based on symptom scores. There were similar PLE rates in females and males. PLE severity correlated with mood (r=0.67), stress (r=0.46), and autistic traits (r=0.18). PLE severity was also related to poverty, lower education attainment, and underemployment. Compared to controls, HR and MR youths were more likely to report lifetime substance use and to have more significant use.

CONCLUSION

Psychosis screening can provide valuable information about individuals and may help identify those who may require clinical assessment and intervention to improve outcomes. This is particularly relevant in many parts of Africa where the resources are limited for treating more advanced illness.

Paranoia and Grandiosity in the General Population: Differential Associations With Putative Causal Factors

Worry, negative self-beliefs, and sleep disturbance have been identified as contributory factors to the onset, maintenance, and severity of paranoia. We tested the specificity of these contributory factors to paranoia compared to grandiosity, a different type of delusional ideation. Data were used from 814 adults from the Nathan Kline Institute-Rockland (NKI-Rockland) study, a general population dataset. Paranoid and grandiose delusional ideation was assessed using the Peters Delusions Inventory (PDI-21) and correlated with self-reported worry (n = 228), negative self-beliefs (n = 485), and sleep quality (n = 655). Correlations were compared using Fisher's r-to-z transform to examine whether the magnitude of relationships differed by delusion type. Paranoia was significantly associated with worry, negative self-belief, and sleep quality. Grandiosity demonstrated significantly weaker relationships with worry and negative self-beliefs. Relationships with sleep quality were similar. We replicate previous reports that worry, negative self-beliefs and sleep quality are associated with paranoid ideation in the general population. We extend these findings by demonstrating that these contributory factors, particularly worry and negative self-beliefs, are associated with paranoid ideation to a greater extent than grandiosity. This suggests a degree of specificity of contributory factors to different types of delusional thinking, supporting the pursuit of specific psychological models and treatments for each delusion type.

Clinical and demographic characteristics of people who smoke versus inject crystalline methamphetamine in Australia: Findings from a pharmacotherapy trial

INTRODUCTION AND AIMS

There has been a rapid increase in smoking crystalline methamphetamine in Australia. We compare the clinical and demographic characteristics of those who smoke versus inject the drug in a cohort of people who use methamphetamine.

DESIGN AND METHODS

Participants (N = 151) were dependent on methamphetamine, aged 18-60 years, enrolled in a pharmacotherapy trial for methamphetamine dependence, and reported either injecting (n = 54) or smoking (n = 97) methamphetamine. Measures included the Timeline Followback, Severity of Dependence Scale, Amphetamine Withdrawal Questionnaire, Craving Experience Questionnaire and the Brief Psychiatric Rating Scale (symptoms of depression, hostility, psychosis and suicidality). Simultaneous regression was used to identify independent demographic correlates of smoking methamphetamine and to compare the clinical characteristics of participants who smoked versus injected.

RESULTS

Compared to participants who injected methamphetamine, those who smoked methamphetamine were younger and less likely to be unemployed, have a prison history or live alone. Participants who smoked methamphetamine used methamphetamine on more days in the past 4 weeks than participants who injected methamphetamine (26 vs. 19 days, P = 0.001); they did not differ significantly in their severity of methamphetamine dependence, withdrawal, craving or psychiatric symptoms (P > 0.05). After adjustment for demographic differences, participants who smoked had lower craving [b (SE) = -1.1 (0.5), P = 0.021] and were less likely to report psychotic symptoms [b (SE) = -1.8 (0.7), P = 0.013] or antidepressant use [b (SE) = -1.1 (0.5), P = 0.022].

DISCUSSION AND CONCLUSIONS

Smoking crystalline methamphetamine is associated with a younger less marginalised demographic profile than injecting methamphetamine, but a similarly severe clinical profile.

Exploration of the paranoia hierarchy in the general population: evidence of an age effect mediated by maladaptive emotion regulation strategies

Introduction: Positive psychotic symptoms are suggested to be more prevalent in early adulthood. However, no previous study has examined a potential age effect especially for paranoia considering social reference and persecution as separated hierarchical dimension. Moreover, no previous study has examined the mechanisms involved in the decrease of paranoia with age. This study aims to explore (1) the age effect on paranoia and (2) whether the age effect is mediated by maladaptive emotion regulation strategies (MERS). Methods: A sample of 1644 participants from the general population completed the Green et al., Paranoid Thoughts Scale with measures of MERS and was split into three age groups (18-29; 30-54; 55-82). Results: Age groups comparisons revealed a significant decrease of social reference with age but not of persecution. Mediation analyses indicated that this age effect was partially mediated by MERS. Additional analyses suggested that social reference moderated the relation between age and persecution. Conclusions: The present study showed that social reference and persecution are not equally affected by age and that MERS are important factors to consider when trying to understand the nature of paranoia. Finally, a younger age and the use of MERS are suggested to be risk factors for developing paranoia.

Increased amygdala-visual cortex connectivity in youth with persecutory ideation

BACKGROUND

Subclinical delusional ideas, including persecutory beliefs, in otherwise healthy individuals are heritable symptoms associated with increased risk for psychotic illness, possibly representing an expression of one end of a continuum of psychosis severity. The identification of variation in brain function associated with these symptoms may provide insights about the neurobiology of delusions in clinical psychosis.

METHODS

A resting-state functional magnetic resonance imaging scan was collected from 131 young adults with a wide range of severity of subclinical delusional beliefs, including persecutory ideas. Because of evidence for a key role of the amygdala in fear and paranoia, resting-state functional connectivity of the amygdala was measured.

RESULTS

Connectivity between the amygdala and early visual cortical areas, including striate cortex (V1), was found to be significantly greater in participants with high (n = 43) v. low (n = 44) numbers of delusional beliefs, particularly in those who showed persistence of those beliefs. Similarly, across the full sample, the number of and distress associated with delusional beliefs were positively correlated with the strength of amygdala-visual cortex connectivity. Moreover, further analyses revealed that these effects were driven by those who endorsed persecutory beliefs.

CONCLUSIONS

These findings are consistent with the hypothesis that aberrant assignments of threat to sensory stimuli may lead to the downstream development of delusional ideas. Taken together with prior findings of disrupted sensory-limbic coupling in psychosis, these results suggest that altered amygdala-visual cortex connectivity could represent a marker of psychosis-related pathophysiology across a continuum of symptom severity.

Appearance-based trust processing in schizophrenia

OBJECTIVES

Schizophrenia is characterized by impaired social interactions and altered trust. In the general population, trust is often based on facial appearance, with limited validity but enormous social consequences. The aim was to examine trust processing in schizophrenia and specifically to examine how people with schizophrenia use facial appearance as well as actual partner fairness to guide trusting decisions.

DESIGN

An experimental economic game study.

METHODS

Here, we tested how patients with schizophrenia and control participants (each N = 24) use facial trustworthiness appearance and partner fairness behaviour to guide decisions in a multi-round Trust Game. In the Trust Game, participants lent money to 'partners' whose facial appearance was either untrustworthy or trustworthy, and who either played fairly or unfairly. Clinical symptoms were measured as well as explicit trustworthiness impressions.

RESULTS

Overall, the patients with schizophrenia showed unimpaired explicit facial trustworthiness impressions and unimpaired facial appearance biases in the Trust Game. Crucially, patients and controls significantly differed so that the patients with schizophrenia did not learn to discriminate in the Trust Game based on actual partner fairness, unlike control participants.

CONCLUSION

A failure to discriminate trust has important implications for everyday functioning in schizophrenia, as forming accurate trustworthiness beliefs is an essential social skill. Critically, without relying on more valid trust cues, people with schizophrenia may be especially susceptible to the misleading effect of appearance when making trusting decisions.

PRACTITIONER POINTS

Findings People with schizophrenia made very similar facial trustworthiness impressions to healthy controls and also used facial appearance to guide trust decisions similarly to controls. However, the patient group were less able to explicitly distinguish between fair and unfair partners based on their behaviour compared with the control group. Moreover, people with schizophrenia failed to use actual partner fairness to guide their financial decisions in the Trust Game, unlike controls, and this impairment was specific to a social task. People with schizophrenia may be particularly reliant on facial appearance when trusting others, as they may struggle to incorporate more valid trustworthiness information in their decision-making, such as actual partner fairness.

Predictors of persisting psychotic like experiences in children and adolescents: A scoping review

BACKGROUND

Subclinical psychotic experiences (PLEs) are among the frequently reported mental health problems in children/adolescents. PLEs identified in cross sectional studies of children/adolescents are associated with current and future mental health problems. These associations are stronger for PLEs that persist over time. Hence, it could be useful to examine which children/adolescents with PLEs at a first assessment (baseline) are more likely to have PLEs at subsequent assessments.

METHODS

We conducted a scoping review of studies that examined whether characteristics of children/adolescents (≤18 years) with PLEs at baseline predict whether PLEs are likely to be persistent or remittent at subsequent assessments. We included studies published between January 2002 and December 2017, conducted on general child/adolescent populations of ≥300 individuals, that provided data on PLEs for at least 2 time points, had available follow-up data for ≥50% of those assessed for PLEs at baseline and targeted for follow-up examination, and reported the differences between individuals with PLEs that persisted or remitted during the study period.

RESULTS

Six studies met our criteria. Each of them investigated a wide range of baseline characteristics but no predictor of persistence was replicated.

CONCLUSIONS

Our knowledge about which children/adolescents with PLEs at an initial assessment are likely to have persistent PLEs at subsequent assessments is sparse. A handful of predictors of persistent PLEs have been investigated so far, and none replicated. A better understanding of these predictors would be an important complement to investigations examining the evolution of PLEs and of mental health problems in children/adolescents.

A Cross-National Investigation of Hallucination-Like Experiences in 10 Countries: The E-CLECTIC Study

Hallucination-like experiences (HLEs) are typically defined as sensory perceptions in the absence of external stimuli. Multidimensional tools, able to assess different facets of HLEs, are helpful for a better characterization of hallucination proneness and to investigate the cross-national variation in the frequencies of HLEs. The current study set out to establish the validity, factor structure, and measurement invariance of the Launay-Slade Hallucinations Scale-Extended (LSHS-E), a tool to assess HLEs. A total of 4419 respondents from 10 countries were enrolled. Network analyses between the LSHS-E and the 3 dimensions of the Community Assessment of Psychic Experiences (CAPE) were performed to assess convergent and divergent validity of the LSHS-E. Confirmatory factor analysis was used to test its measurement invariance. The best fit was a 4-factor model, which proved invariant by country and clinical status, indicating cross-national stability of the hallucination-proneness construct. Among the different components of hallucination-proneness, auditory-visual HLEs had the strongest association with the positive dimension of the CAPE, compared with the depression and negative dimensions. Participants who reported a diagnosis of a mental disorder scored higher on the 4 LSHS-E factors. Small effect size differences by country were found in the scores of the 4 LSHS-E factors even after taking into account the role of socio-demographic and clinical variables. Due to its good psychometric properties, the LSHS-E is a strong candidate tool for large investigations of HLEs.

Rethinking schizophrenia through the lens of evolution: shedding light on the enigma

Schizophrenia refers to a complex psychiatric illness characterized by the heterogenic presence of positive, negative and cognitive symptoms occurring in all human societies. The fact that the disorder lacks a unifying neuropathology, presents a decreased fecundity of the affected individuals and has a cross-culturally stable incidence rate, makes it necessary for an evolutionary explanation that fully accounts for the preservation of “schizophrenic genes” in the global human genepool, explaining the potential sex differences and the heterogeneous cognitive symptomatology of the disorder and is consistent with the neuropsychological, developmental and evolutionary findings regarding the human brain. Here we proposed a new evolutionary framework for schizophrenia that is consistent with findings presented in different dimensions, considering the disorder as a form of brain functioning that allows us to adapt to the environment and, ultimately, maintain the survival of the species. We focus on the epigenetic regulation of thalamic interneurons as a major player involved in the development of the clinical picture characteristic of schizophrenia.

Auditory hallucinations across the lifespan: a systematic review and meta-analysis

BACKGROUND

Auditory Hallucinations (AH) are nowadays regarded as symptoms following a continuum; from a (transient) phenomenon in healthy individuals on one end to a symptom of (psychiatric) illnesses at the other. An accumulating number of epidemiological studies focused on the prevalence of AH in the general population, but results vary widely. The current meta-analysis aims to synthesize existing evidence on lifetime prevalence of AH across the lifespan.

METHODS

We conducted a quantitative review and meta-analysis according to PRISMA guidelines. Studies were combined to calculate a mean lifetime general population AH prevalence rate. Moreover, prevalences were calculated for four age groups: children (5-12 years), adolescents (13-17 years), adults (18-60 years) and elderly (⩾60 years).

RESULTS

We retrieved 25 study samples including 84 711 participants. Mean lifetime prevalence rate of AH was 9.6% (95% CI 6.7-13.6%). The mean lifetime prevalence was similar in children (12.7%) and adolescents (12.4%), but these two groups differed significantly from the adults (5.8%) and the elderly (4.5%). Significant heterogeneity indicated that there is still dispersion in true prevalence rates between studies, even within the different age categories.

CONCLUSIONS

Current meta-analysis shows that AH are quite common (up to one in ten individuals) in the general population during lifetime, with children and adolescents reporting these experiences significantly more often compared with adults and elderly. Large follow-up studies on the longitudinal course of AH are needed to reveal associated risk and resilience factors.

Correlation Between Levels of Delusional Beliefs and Perfusion of the Hippocampus and an Associated Network in a Non-Help-Seeking Population

BACKGROUND

Delusions are a defining and common symptom of psychotic disorders. Recent evidence suggests that subclinical and clinical delusions may represent distinct stages on a phenomenological and biological continuum. However, few studies have tested whether subclinical psychotic experiences are associated with neural changes that are similar to those observed in clinical psychosis. For example, it is unclear if overactivity of the hippocampus, a replicated finding of neuroimaging studies of schizophrenia, is also present in individuals with subclinical psychotic symptoms.

METHODS

To investigate this question, structural and pulsed arterial spin labeling scans were collected in 77 adult participants with no psychiatric history. An anatomical region of interest approach was used to extract resting perfusion of the hippocampus, and 15 other regions, from each individual. A self-report measure of delusional ideation was collected on the day of scanning.

RESULTS

The level of delusional thinking (number of beliefs [r = .27, p = .02]), as well as the associated level of distress (r = .29, p = .02), was significantly correlated with hippocampal perfusion (averaged over right and left hemispheres). The correlations remained significant after controlling for age, hippocampal volume, symptoms of depression and anxiety, and image signal-to-noise ratio, and they were confirmed in a voxelwise regression analysis. The same association was observed in the thalamus and parahippocampal, lateral temporal, and cingulate cortices.

CONCLUSIONS

Similar to patients with schizophrenia, non-help-seeking individuals show elevated perfusion of a network of limbic regions in association with delusional beliefs.

Psychosis as an Evolutionary Adaptive Mechanism to Changing Environments

Background: From an evolutionary perspective it is remarkable that psychotic disorders, mostly occurring during fertile age and decreasing fecundity, maintain in the human population. Aim: To argue the hypothesis that psychotic symptoms may not be viewed as an illness but as an adaptation phenomenon, which can become out of control due to different underlying brain vulnerabilities and external stressors, leading to social exclusion. Methods: A literature study and analysis. Results: Until now, biomedical research has not unravelld the definitive etiology of psychotic disorders. Findings are inconsistent and show non-specific brain anomalies and genetic variation with small effect sizes. However, compelling evidence was found for a relation between psychosis and stressful environmental factors, particularly those influencing social interaction. Psychotic symptoms may be explained as a natural defense mechanism or protective response to stressful environments. This is in line with the fact that psychotic symptoms most often develop during adolescence. In this phase of life, leaving the familiar, and safe home environment and building new social networks is one of the main tasks. This could cause symptoms of "hyperconsciousness" and calls on the capacity for social adaptation. Conclusions: Psychotic symptoms may be considered as an evolutionary maintained phenomenon.Research investigating psychotic disorders may benefit from a focus on underlying general brain vulnerabilities or prevention of social exclusion, instead of psychotic symptoms.

The Italian version of the 92-item Prodromal Questionnaire: Concurrent validity with the SIPS and factor analysis in a sample of 258 outpatients aged 11-36years

BACKGROUND

Current early screeners for psychosis-risk states have still to prove ability in identifying at-risk individuals. Among screeners, the 92-item Prodromal Questionnaire (PQ-92) is often used. We aimed to assess the validity of its Italian translation in a large Italian adolescent and young adult help-seeking sample.

METHODS

We included all individuals aged 12-36years seeking help at psychiatric mental health services in a large semirural Roman area (534,600 population) who accepted to participate. Participants completed the Italian version of the PQ-92 and were subsequently assessed with the Structured Interview of Prodromal/Psychosis-Risk Syndromes (SIPS). We examined diagnostic accuracy (sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios) and content, concurrent, and convergent validity between PQ-92 and SIPS using Cronbach's alpha, Cohen's kappa, and Spearman's rho, respectively. We tested the validity of adopted cut-offs through Receiver Operating Characteristic (ROC) curves plotted against SIPS diagnoses and the instrument's factor-structure through Principal Component Analysis.

RESULTS

PQ-92 showed high internal consistency, acceptable diagnostic accuracy and concurrent validity, and excellent convergent validity. ROC analyses pointed to scores of 18 on the Positive subscale and 36 on the total PQ-92 as best cut-offs. The Scree-test identified a four-factor solution as fitting best.

CONCLUSIONS

Psychometric properties of Italian PQ-92 were satisfactory. Optimal cut-offs were confirmed at ≥18 on the positive subscale, but at ≥36 on the total scale was able to identify more SIPS-positive cases.

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

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

Examination of humiliation and past maladaptive family context in persecutory ideation: An exploratory study

INTRODUCTION

Previous studies have demonstrated that early interpersonal trauma is involved in the development of persecutory ideation. However, the specific influence of past and current social and familial variables has never been previously explored. Thus, the aim of the present study was to examine the potential role of current and past interpersonal humiliation events (e.g. to be cruelly criticized, submitted, bullied, insulted, scorned) and a negative family context on the development of persecutory ideation.

METHODS

Current and past interpersonal humiliation events (Humiliation Inventory), a negative family context (Risky Family Questionnaire) and degree of persecutory ideation (Peters et al. Delusions Inventory) were assessed in a sample of 175 non-clinical participants (range=18-62years, 81% women and 19% men) with the help of an online survey.

RESULTS

A pattern of significant correlations emerged, in particular, between persecutory ideation, the past and present interpersonal humiliation, and negative primary family context. Moreover, hierarchical multiple regression analysis revealed that, among the various variables, past interpersonal humiliation events and a negative family context significantly predicted higher levels of persecutory ideation.

CONCLUSIONS

For the first time in the literature, this study provides preliminary evidence that past interpersonal humiliation events and a negative family context are related to the development of persecutory ideation. In addition, we showed that past interpersonal humiliation events, but not the fear of current events, have an impact on the development of persecutory ideation. These results suggest that the amelioration of early familial and social contexts may help to prevent the development of persecutory ideation.

Invariance of factor structure of the 21-item Peters et al. Delusions Inventory (PDI-21) over time and across samples

The present study aimed to explore the latent structure of the 21-item Peters et al. Delusions Inventory (PDI-21) and to test the invariance of its factor structure over time and across samples. The PDI-21 was administered in two samples; one consisting of 1655 undergraduate students investigated in three waves, each separated by six months; and another consisting of 196 outpatients with schizophrenia. Exploratory factor analysis was performed to explore the internal structure of the PDI-21 based on number of beliefs and the grand total scores separately. The number of factors was determined by optimal implementation of parallel analysis. Confirmatory factor analysis, cross-time and cross-sample invariance analyses were carried out with Mplus. Both exploratory factor analysis and the optimal implementation of parallel analysis (based on the number of beliefs and the total score of the PDI-21) suggested a one-factor solution. However, the confirmatory factor analysis revealed a single-dimension structure based on number of beliefs only, which exhibited goodness of fit and stability across time and samples. Our study demonstrated a single-dimension structure of the PDI-21, which can be widely used in screening the number of delusional ideations both in clinical and non-clinical populations.

Maladaptive emotion regulation strategies and stress sensitivity mediate the relation between adverse life events and attenuated positive psychotic symptoms

INTRODUCTION

There is now solid evidence for a relation between adverse life events (ALE) and psychotic symptoms in patients with psychosis and in the general population. A recent study has shown that this relation may be partially mediated by stress sensitivity, suggesting the influence of other factors. The aim of this study was to assess the mediation effect of emotion regulation strategies and stress sensitivity in the relation between ALE and attenuated positive psychotic symptoms (APPS) in the general population.

METHODS

Hundred and twelve healthy volunteers were evaluated with measures of APPS, emotion regulation strategies, ALE and stress sensitivity.

RESULTS

Results demonstrated that the relation between ALE, hallucination and delusion proneness was completely mediated by maladaptive emotion regulation strategies, but not by stress sensitivity. However, in addition to maladaptive emotion regulation strategies, stress sensitivity demonstrated a mediation effect between ALE and attenuated positive psychotic positive symptoms when positive psychotic symptoms were grouped together.

CONCLUSIONS

There are probably several possible trajectories leading to the formation of positive psychotic symptoms and the results of the present study reveal that one such trajectory may involve the maladaptive regulation of negative emotions alongside a certain general vulnerability after experiencing ALE.

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

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

Developmental course of subclinical positive and negative psychotic symptoms and their associations with genetic risk status and impairment

The proneness-persistence-impairment (PPI) model states that psychotic experiences are more likely to lead to impairment if their expression becomes persistent. Higher genetic risk for psychosis is known to affect proneness and persistence of subclinical positive symptoms. Less is known about potential effects of genetic risk on the course of subclinical negative symptoms, impairment, and their subsequent associations. The current study examined these issues in a large sample (n=1131), consisting of individuals with higher genetic risk (siblings of patients with psychotic disorders, n=703) and lower genetic risk (controls without a family member with lifetime psychosis, n=428). Psychotic experiences were assessed with the CAPE questionnaire, at two time points three years apart. Participants were allocated to one of four groups representing developmental course: stable low, decreasing, increasing or persisting subclinical positive/negative symptoms. Lifetime clinical psychosis was an exclusion criterion at baseline. Higher genetic risk status was found to be associated with a persisting course of both subclinical positive and negative symptoms, symptom-related distress and functional impairment. There is no evidence for an effect of genetic risk status on the association between developmental course and impairment. The results of the current study underline the importance of assessing psychotic experiences in the context of genetic risk, multidimensional and over time. Additionally, the current findings both underscore and contribute to the PPI model: psychotic experiences are more likely to lead to impairment if their expression becomes persistent, both in individuals with higher and lower genetic risk for psychosis.

Correlates of transient versus persistent psychotic symptoms among dependent methamphetamine users

This study examined correlates of transient versus persistent psychotic symptoms among people dependent on methamphetamine. A longitudinal prospective cohort study of dependent methamphetamine users who did not meet DSM-IV criteria for lifetime schizophrenia or mania. Four non-contiguous one-month observation periods were used to identify participants who had a) no psychotic symptoms, (n=110); (b) psychotic symptoms only when using methamphetamine (transient psychotic symptoms, n=85); and, (c) psychotic symptoms both when using methamphetamine and when abstaining from methamphetamine (persistent psychotic symptoms, n=37). Psychotic symptoms were defined as a score of 4 or greater on any of the Brief Psychiatric Rating Scale items of suspiciousness, hallucinations or unusual thought content. Relative no psychotic symptoms, both transient and persistent psychotic symptoms were associated with childhood conduct disorder and comorbid anxiety disorders. Earlier onset methamphetamine use and being male were more specifically related to transient psychotic symptoms, while a family history of a primary psychotic disorder and comorbid major depression were specifically related to persistent psychotic symptoms. We conclude that there are overlapping but also distinct clinical correlates of transient versus persistent psychotic symptoms, suggesting potentially heterogeneous etiological pathways underpinning the psychotic phenomena seen amongst people who use methamphetamine.

A preliminary investigation into theory of mind and attributional style in adults with grandiose delusions

INTRODUCTION

A preliminary cognitive model of grandiose delusions has been put forward suggesting that persecutory and grandiose delusions shared distinct, yet overlapping psychological processes. This study aims to test this model and hypothesises that participants experiencing grandiose delusions may demonstrate a theory of mind (ToM) impairment and differences in attributional style compared to a control group.

METHODS

A cross-sectional design compared the performance of 18 individuals with grandiose delusions to a control group of 14 participants with depression. ToM was measured using a non-verbal joke appreciation task and a verbal stories task. Attributional style was measured using the internal, personal and situational attributions questionnaire.

RESULTS

Participants experiencing grandiose delusions performed significantly worse on both ToM tasks compared to controls. Furthermore, these participants provided significantly more atypical answers when explaining the joke behind the ToM cartoons. No differences for subjective funniness ratings or attributional style were found.

CONCLUSIONS

This preliminary study indicated participants experiencing grandiose delusions have ToM impairments which may contribute to the maintenance of this symptom.

Examining the Psychosis Continuum

The notion that psychosis may exist on a continuum with normal experience has been proposed in multiple forms throughout the history of psychiatry. However, in recent years there has been an exponential increase in efforts aimed at elucidating what has been termed the 'psychosis continuum'. The present review seeks to summarize some of the more basic characteristics of this continuum and to present some of the recent findings that provide support for its validity. While there is still considerable work to be done, the emerging data holds considerable promise for advancing our understanding of both risk and resilience to psychiatric disorders characterized by psychosis.

Childhood trauma and schizotypy: a systematic literature review

BACKGROUND

Schizotypy is a complex concept, commonly defined as a genetic vulnerability to schizophrenia that falls on a continuum between healthy variation and severe mental illness. There is a growing body of evidence supporting an association between childhood trauma and increased psychotic experiences and disorders. However, the evidence as to whether there is a similar association with schizotypy has yet to be systematically synthesized and assessed.

METHOD

We conducted a systematic search of published articles on the association between childhood trauma and schizotypy in four major databases. The search covered articles from 1806 to 1 March 2013 and resulted in 17,003 articles in total. Twenty-five original research studies met the eligibility criteria and were included in this review.

RESULTS

All 25 studies supported the association between at least one type of trauma and schizotypy, with odds ratios (ORs) ranging between 2.01 and 4.15. There was evidence supporting the association for all types of trauma, with no differential effects. However, there was some variability in the quality of the studies, with most using cross-sectional designs. Individuals who reported adverse experiences in childhood scored significantly higher on positive and negative/disorganized schizotypy compared to those who did not report such experiences.

CONCLUSIONS

All forms of childhood trauma and other stressful events (e.g. bullying) were found to be associated with schizotypy, with especially strong associations with positive schizotypy. However, because of the methodological limitations of several studies and a lack of further exploration of different possible mechanistic pathways underlying this association, more research is required.

Self-reported psychotic-like experiences in individuals with obsessive-compulsive disorder versus schizophrenia patients: characteristics and moderation role of trait anxiety

Psychotic-like experiences (PLEs) have been found to manifest themselves on a continuum spanning both the general and clinical populations. Despite robust evidence that anxiety disorders are associated with increased risk of PLEs, little is known about their characteristics in obsessive compulsive disorder (OCD). Therefore, this study aimed to explore the phenomenological similarities and differences of PLEs in OCD versus schizophrenia patients and healthy controls, and to test the impact of distress symptomatology on PLEs in OCD patients. The survey included the Peter et al. Delusion Inventory, the Launay-Slade Hallucinations Scale, the Beck Depression Inventory II, the Spielberger State-Trait Anxiety Inventory, and measures of severity of OCD and schizophrenia symptoms. Considering the clinical groups as a whole, few differences were found for both delusions and hallucination-like experiences. Nevertheless, after controlling for emotional distress differences between OCD and schizophrenia patients in some PLEs became significant. Moreover, obsessive symptoms moderated by anxiety trait predicted levels of delusion-like experiences in OCD patients. This study highlights PLEs are also present in OCD patients, in particularly in presence of higher emotional distress and that anxiety trait plays a relevant role in the development and maintenance of delusion-like experiences in OCD patients.

Schizotypal Traits are Associated with Poorer Executive Functioning in Healthy Adults

Previous research has shown mild forms of the neurocognitive impairments seen in schizophrenia among healthy individuals exhibiting high schizotypal traits. This study aimed to explore associations between schizotypy and cognitive performance in an adult community sample. Ninety-five females and 79 males completed the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE), which measures four separable aspects of schizotypy: cognitive disorganization, unusual experiences, introvertive anhedonia, and impulsive non-conformity. Subsequently, participants were administered a neurocognitive battery incorporating measures of executive skills including inhibition, cognitive flexibility, reasoning, and problem solving along with measures of attention and processing speed and both verbal and spatial working memory. In line with predictions, the current study found that higher scores on the subscales of unusual experiences, cognitive disorganization, and impulsive non-conformity related to worse performance on a measure of inhibition. Additionally, as introvertive anhedonia increased, both attention and processing speed and reasoning and problem-solving performance became more impaired. In conclusion, this study extends schizotypy literature by examining the subscales of the O-LIFE, and enables inferences to be drawn in relation to cognitive impairment in schizophrenia.

The relation between childhood maltreatment and psychosis in patients with schizophrenia and non-psychiatric controls

Several lines of evidence suggest that childhood maltreatment is associated with an increased risk for both psychotic disorders and subclinical psychotic-like experiences in the general population. Few studies, however, have sought to examine whether the strength of this relationship is comparable across patient and non-patient groups. The present study sought to compare the strength of the association between childhood maltreatment and self-reported psychotic symptoms in 447 healthy adult volunteers and 184 stable outpatients with schizophrenia or schizoaffective disorder. Strong positive correlations between childhood maltreatment and self-reported symptoms were observed in both groups. Although patients scored significantly higher than controls on both history of childhood maltreatment and self-reported symptoms, the strength of the relationship did not differ between groups. These data provide strong support for etiological continuity between subclinical psychotic symptoms and psychotic disorders.

Experiences of possession and paranormal phenomena among women in the general population: are they related to traumatic stress and dissociation?

This study sought to determine the prevalence of experiences of possession and paranormal phenomena (PNP) in the general population and their possible relations to each other and to traumatic stress and dissociation. The study was conducted on a representative female sample recruited from a town in central eastern Turkey. The Dissociative Disorders Interview Schedule, the posttraumatic stress disorder (PTSD) and borderline personality disorder sections of the Structured Clinical Interviews for DSM-IV Axis-I and Personality Disorders, and the Childhood Abuse and Neglect Questionnaire were administered to 628 women. Of these, 127 (20.2%) women reported at least 1 type of PNP and 13 (2.1%) women reported possession. Women with a dissociative disorder reported all types of possession and PNP (except telepathy) more frequently than those without. Whereas women with a trauma history in childhood and adulthood or PTSD reported possession more frequently than those without, PNP were associated with childhood trauma only. Factor analysis yielded 4 dimensions: possession by and/or contact with nonhuman entities, extrasensory communications, possession by a human entity, and precognition. These factors correlated with number of secondary features of dissociative identity disorder and Schneiderian symptoms. Latent class analysis identified 3 groups. The most traumatized group, with predominantly dissociative and trauma-related disorders, had the highest scores on all factors. Notwithstanding their presence in healthy individuals, possession and PNP were associated with trauma and dissociation in a subgroup of affected participants. Both types of experience seem to be normal human capacities of experiencing that may be involved in response to traumatic stress. Given the small numbers, this study should be considered preliminary.

Sexual minority status and psychotic symptoms: findings from the Netherlands Mental Health Survey and Incidence Studies (NEMESIS)

BACKGROUND

Ethnic minority position is associated with increased risk for psychotic outcomes, which may be mediated by experiences of social exclusion, defeat and discrimination. Sexual minorities are subject to similar stressors. The aim of this study is to examine whether sexual minorities are at increased risk for psychotic symptoms and to explore mediating pathways.

METHOD

A cross-sectional survey was performed assessing cumulative incidence of psychotic symptoms with the Composite International Diagnostic Interview in two separate random general population samples (NEMESIS-1 and NEMESIS-2). Participants were sexually active and aged 18-64 years (n = 5927, n = 5308). Being lesbian, gay or bisexual (LGB) was defined as having sexual relations with at least one same-sex partner during the past year. Lifetime experience of any psychotic symptom was analysed using logistic regression, adjusted for gender, educational level, urbanicity, foreign-born parents, living without a partner, cannabis use and other drug use.

RESULTS

The rate of any psychotic symptom was elevated in the LGB population as compared with the heterosexual population both in NEMESIS-1 [odds ratio (OR) 2.56, 95% confidence interval (CI) 1.71-3.84] and NEMESIS-2 (OR 2.30, 95% CI 1.42-3.71). Childhood trauma, bullying and experience of discrimination partly mediated the association.

CONCLUSIONS

The finding that LGB orientation is associated with psychotic symptoms adds to the growing body of literature linking minority status with psychosis and other mental health problems, and suggests that exposure to minority stress represents an important mechanism.

Diagnostic criteria as dysfunction indicators: bridging the chasm between the definition of mental disorder and diagnostic criteria for specific disorders

According to the introduction to the Diagnostic and Statistical Manual of Mental Disorders (DSM), Fifth Edition, each disorder must satisfy the definition of mental disorder, which requires the presence of both harm and dysfunction. Constructing criteria sets to require harm is relatively straightforward. However, establishing the presence of dysfunction is necessarily inferential because of the lack of knowledge of internal psychological and biological processes and their functions and dysfunctions. Given that virtually every psychiatric symptom characteristic of a DSM disorder can occur under some circumstances in a normally functioning person, diagnostic criteria based on symptoms must be constructed so that the symptoms indicate an internal dysfunction, and are thus inherently pathosuggestive. In this paper, we review strategies used in DSM criteria sets for increasing the pathosuggestiveness of symptoms to ensure that the disorder meets the requirements of the definition of mental disorder. Strategies include the following: requiring a minimum duration and persistence; requiring that the frequency or intensity of a symptom exceed that seen in normal people; requiring disproportionality of symptoms, given the context; requiring pervasiveness of symptom expression across contexts; adding specific exclusions for contextual scenarios in which symptoms are best understood as normal reactions; combining symptoms to increase cumulative pathosuggestiveness; and requiring enough symptoms from an overall syndrome to meet a minimum threshold of pathosuggestiveness. We propose that future revisions of the DSM consider systematic implementation of these strategies in the construction and revision of criteria sets, with the goal of maximizing the pathosuggestiveness of diagnostic criteria to reduce the potential for diagnostic false positives.

Psychometric properties of Peters et al. delusions inventory-21 in adolescence

We explored the psychometric properties of the Korean version of the Peters et al. delusions inventory-21 (PDI-21) and evaluated the item characteristics of the PDI-21 compared with the Magical Ideation Scale (MIS) in Korean community adolescents. Survey participants comprised 310 Year 10 students who were assessed with the following instruments: the PDI-21, the MIS, the Schizotypal Personality Scale (STA) and the symptom checklist-90-R (SCL-90-R). The item characteristics of the PDI-21 and MIS were also explored using item response theory (IRT). The PDI-21 exhibited good internal consistency and demonstrated significant correlations with the MIS, STA and all subscale scores of the SCL-90-R, indicating psychological distress in adolescents with high PDI-21 scores. We also found through IRT analysis that the PDI-21 provides more information at the lower range and the MIS at the higher range of delusion proneness. Our findings suggest that the PDI-21 is an effective and reliable self-report measure for assessment of delusion proneness and that the PDI-21 and the MIS may be used complementarily to assess a broad range of delusion proneness among community adolescents.

Adolescent bullying, cannabis use and emerging psychotic experiences: a longitudinal general population study

BACKGROUND

Using longitudinal and prospective measures of psychotic experiences during adolescence, we assessed the risk of developing psychosis in three groups showing low, increasing and elevated psychotic experiences associated with bullying by peers and cannabis use in a UK sample of adolescents. Method Data were collected by self-report from 1098 adolescents (mean age 13.6 years; 60.9% boys) at five separate time points, equally separated by 6 months, across a 24-month period. General growth mixture modelling identified three distinct trajectories of adolescents reporting psychotic experiences: elevated, increasing and low.

RESULTS

Controlling for cannabis use, bullying by peers significantly predicted change in psychotic experiences between Time 2 and Time 5 in adolescents belonging to the increasing group. No effect was found for the elevated or low groups. Controlling for bullying, an earlier age of cannabis use and cannabis use more than twice significantly predicted change in psychotic experiences in adolescents belonging to the increasing group. Cannabis use at any age was significantly associated with subsequent change in psychotic experiences in the low group. Reverse causal associations were examined and there was no evidence for psychotic experiences at Time 1 predicting a subsequent change in cannabis use between Times 2 and 5 in any trajectory group.

CONCLUSIONS

Bullying by peers and cannabis use are associated with adolescents' reports of increasing psychotic experiences over time. Further research into the longitudinal development of psychosis in adolescence and the associated risk factors would allow for early intervention programmes to be targeted more precisely.

How psychotic-like are paranormal beliefs?

BACKGROUND AND OBJECTIVES

Paranormal beliefs and Psychotic-like Experiences (PLE) are phenotypically similar and can occur in individuals with psychosis but also in the general population; however the relationship of these experiences for psychosis risk is largely unclear. This study investigates the association of PLE and paranormal beliefs with psychological distress.

METHODS

Five hundred and three young adults completed measures of paranormal beliefs (Beliefs in the Paranormal Scale), psychological distress (General Health Questionnaire), delusion (Peters et al. Delusions Inventory), and hallucination (Launay-Slade Hallucination Scale) proneness.

RESULTS

The frequency and intensity of PLE was higher in believers in the paranormal compared to non-believers, however psychological distress levels were comparable. Regression findings confirmed that paranormal beliefs were predicted by delusion and hallucination-proneness but not psychological distress.

LIMITATIONS

The use of a cross-sectional design in a specific young adult population makes the findings exploratory and in need of replication with longitudinal studies.

CONCLUSIONS

The predictive value of paranormal beliefs and experiences for psychosis may be limited; appraisal or the belief emotional salience rather than the belief per se may be more relevant risk factors to predict psychotic risk.

Psychometric properties of the Peters et al Delusions Inventory 21 in college students

Delusions show high prevalence in the general population and can be considered a risk marker for psychotic disorders. Although the assessment of these experiences has made considerable progress in recent years, there is still room for improvement in the measurement quality of the self-reports available for such assessment. The goal of the present work was to analyze the measurement quality of the Peters et al Delusions Inventory 21 (PDI-21) in Spanish college students. The final sample was made up of 660 participants (29.5% men) with a mean age of 20.3 years (SD, 2.6 years). The results revealed that a high percentage of the sample reported some symptom of paranoia. Analysis of the internal structure of the PDI-21 by means of exploratory factor analysis based on the tetrachoric correlation matrix yielded an essentially unidimensional solution. Cronbach α for the total score was .91. Scores on the PDI-21 correlated in a statistically significant fashion with trait and state anxiety and negative affect. These results provide new evidence of the validity of the PDI-21 and endorse its use as a measurement instrument for assessing the extended psychosis phenotype in nonclinical population.

Self-reported psychotic symptoms in the general population: correlates in an Iranian urban area

BACKGROUND

Psychosis exists in the community as a continuum of severity. Here, we examine the correlates of self-reported psychotic symptoms in an urban catchment area of Iran.

SAMPLING AND METHODS

Two thousand one hundred and fifty-eight participants (age 18-65 years) residing in southern Tehran (the capital city of Iran) were interviewed using the psychoticism and paranoia dimensions of the Symptom Checklist-90-Revised (SCL-90-R) to assess the severity of psychotic symptoms. Other dimensions of the SCL-90-R assessing nonpsychotic symptoms and a sociodemographic questionnaire were also used. Paykel's Interview for Recent Life Events was used to assess stressful life events.

RESULTS

Independent associations were observed between younger age, female gender, stressful life events and dimensions of depression, anxiety, hostility, obsessive-compulsive symptoms and interpersonal sensitivity and psychoticism. Independent associations were also observed for marital problems, unemployment, stressful life events and dimensions of depression, anxiety, hostility, interpersonal sensitivity and phobic anxiety with paranoid ideation. There was also a trend toward an association between higher educational levels and the severity of psychotic symptoms, particularly paranoid ideation.

CONCLUSIONS

Most of the previously accepted correlations for psychotic symptoms in the community were replicated. An unexpected association between paranoia and female gender, and a trend toward higher rates of psychotic symptoms in more educated participants, were in contrast with the studies in developed settings. The insufficient coverage of psychosis-relevant questions from the SCL-90-R for the entire psychotic diagnostic spectrum should be considered a limitation.

Replication of the five-dimensional structure of positive psychotic experiences in young adulthood

Previous work has examined the structure of subclinical positive psychotic experiences. The current study, using confirmatory factor analysis in a general population sample of young adult females, replicated a five-dimensional model, which showed excellent model fit. The results suggest stability of the five-dimensional model across adolescent and young adult life.