Do different psychotic experiences differentially predict need for care in the general population?

Factors impacting intent to seek treatment within youth at clinical high risk for psychosis

Existing work indicates that there is unmet need for care in those at clinical high risk (CHR) for psychosis. However, research on the factors that drive treatment seeking behaviors in this population is limited. Further, it is unknown how help-seeking behavior in CHR individuals compares to those seen in mood disorders, who have a higher rate of treatment seeking behavior. Participants (n = 559) completed an assessment of their intent to seek mental health treatment, attenuated psychosis-risk symptoms, and psychiatric symptoms and diagnoses. Participants were divided into CHR (n = 91), Mood Disorders (MD) (n = 72), or Community Controls (CC) groups (n = 396), whose intent to seek treatment was compared. Associations between intent to seek treatment with past treatment, depression, anxiety, positive and negative symptoms, distress from symptoms, intelligence quotient (IQ) estimates, and insight were assessed in CHR individuals. Further, it was assessed how this differs for the MD group. The MD group reported higher intent to seek treatment than CHR individuals, which reported higher intent to seek treatment than the CC group. In those at CHR, previous treatment, greater depression and anxiety severity, and higher distress all independently predicted higher intent to seek treatment. Depression predicted intent to seek treatment in both MD and CHR individuals. Previous treatment predicted intent to seek treatment in those at CHR. Our findings suggest that depression and past treatment utilization are critical factors in increasing intent to seek treatment in those at CHR, potentially serving as important targets for engaging this population in treatment.

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.

Sexual Minority Status and Psychotic Experiences Among Young Adult College Students in the United States

2020-2021 Healthy Minds Study, and used multivariable logistic regression to examine the associations between sexual minority status and psychotic experiences, adjusting for age, gender, and race/ethnicity. We then tested whether psychosocial factors accounted for the association. Sexual minority status was associated with 1.87 times greater odds of having psychotic experiences over the past 12 months (aOR: 1.87; 95% CI: 1.77-1.99; N = 110,551). Several factors mediated the association between sexual orientation and psychotic experiences such as loneliness (26.93%), anxiety (30.90%), depression (33.18%), and marijuana use (13.95%); all factors together accounted for 59.01% of the association between sexual minority status and psychotic experiences. Food insecurity, recent abuse, and discrimination did not significantly mediate the association. Findings should raise clinical awareness that psychotic experiences are more common among sexual minorities than among heterosexuals, which is largely explained by mental health factors, calling for targeted outreach and intervention.

Evaluation of reliability and validity of the Persian version of Peters et al. delusions inventory (PDI-40) in iranian non-clinical and clinical samples

BACKGROUND

Some individuals may manifest psychotic symptoms that do not fulfill the requisite clinical criteria for a formal diagnosis of psychosis. The assessment of susceptibility to delusions, encompassing both clinical and non-clinical cohorts, frequently makes use of the Peters et al. Delusions Inventory (PDI-40). This study aimed to evaluate the reliability and validity of the Persian version of Peters et al. Delusions Inventory (PDI-40) in Iranian non-clinical and clinical samples.

METHODS

The present study employed a cross-sectional, correlational design in 2020. A total of 1402 Iranian participants were recruited for the study, which consisted of three distinct stages. The first stage involved an Exploratory Factor Analysis (EFA) conducted on a non-clinical sample of 512 participants. The second stage comprising different non-clinical sample 764 participants to perform a Confirmatory Factor Analysis (CFA). In the third stage, a clinical sample of 126 psychotic patients was compared to a non-clinical sample. All participants completed the PDI-40, the Community Assessment of Psychotic Experiences (CAPE-42), and the Depression, Anxiety, and Stress Scale (DASS-21). The internal structure of PDI-40 was examined through the analysis of its factor structure using LISREL 8.8.

RESULTS

The EFA analysis unveiled nine components within Persian version of PDI-40. The CFA analysis demonstrated an excellent fit of the nine-factor structure of Persian PDI-40 to the data. The total score exhibited high internal reliability, as indicated by Cronbach's alpha coefficient of 0.92. Moreover, Persian PDI-40 exhibited satisfactory evidence of convergent validity, as significant correlations were observed between dimensions of PDI-40 and subscales of CAPE-42 and DASS-21. Lastly, findings indicated that psychotic participants scored higher than non-clinical participants in all components of the PDI-40(p < 0.05).

CONCLUSION

Persian version of the PDI-40 demonstrates strong reliability and validity for assessing delusion proneness in both non-clinical and clinical samples in Iran. The observed distinctions between psychotic and non-clinical participants underscore its potential as a valuable tool for discerning delusion proneness in diverse contexts.

Psychotic-like experiences in non-clinical subgroups with and without specific beliefs

BACKGROUND

Assuming a transdiagnostic and extended psychosis phenotype, psychotic-like experiences (PLEs) and psychotic symptoms are on a phenomenological and temporal continuum between clinical and non-clinical populations. Recent research points towards differences in PLE proneness in different subgroups and clinical impact of different PLE subtypes. This study examines the prevalence of PLEs in three groups of individuals with and without specific sets of beliefs aiming to elucidate the question whether proneness to PLEs varies according to traditional versus less traditional supernatural beliefs.

METHODS

The anonymized 16-item version of the Prodromal Questionnaire (PQ-16) was used to assess PLEs in three groups including individuals with religious beliefs (RB), belief in esoterism and paranormal phenomena (EB), and those embedded in scientific evidence approach and scepticism towards para-scientific theories (non-believers, NB). Male and female participants between 18 and 90 years were eligible for participation.

RESULTS

The sample comprised 159 individuals including 41 RB individuals, 43 EB individuals, and 75 NB individuals. The mean PQ-16 score of the EB individuals (6.86 ± 4.13) was significantly higher compared to NB individuals (3.43 ± 2.99) and to RB individuals (3.38 ± 3.23) with almost twice the score (both p-values < 0.001). There was no significant difference between the PQ-16 scores of the NB group and the RB group (p = 0.935). No significant impact of age (p = 0.330) and gender (p = 0.061) was found on the PQ16-Score. Group affiliation to esoterism was associated with a higher PQ-16 score compared to group affiliation to religious beliefs (p < 0.001) and group affiliation to scepticism (p = 0.011), while the latter two did not differ significantly (p = 0.735). No significant difference was found between the three groups in the degree of distress related to the affirmatively answered PQ-16 items (p = 0.74).

CONCLUSION

Under the assumption of a transdiagnostic psychosis phenotype, our findings provide more insight which subgroups within non-clinical samples have a higher likelihood of reporting PLEs.

A Population-Based Cohort Study Examining the Incidence and Impact of Psychotic Experiences From Childhood to Adulthood, and Prediction of Psychotic Disorder

OBJECTIVE

The authors investigated the incidence, course, and outcome of psychotic experiences from childhood through early adulthood in the general population and examined prediction of psychotic disorder.

METHODS

This was a population-based cohort study using the semistructured Psychosis-Like Symptoms Interview at ages 12, 18, and 24 (N=7,900 with any data). Incidence rates were estimated using flexible parametric modeling, and positive predictive values (PPVs), sensitivity, specificity, and area under the curve were estimated for prediction.

RESULTS

The incidence rate of psychotic experiences increased between ages 13 and 24, peaking during late adolescence. Of 3,866 participants interviewed at age 24, 313 (8.1%, 95% CI=7.2, 9.0) had a definite psychotic experience since age 12. A total of 109 individuals (2.8%) met criteria for a psychotic disorder up to age 24, of whom 70% had sought professional help. Prediction of current psychotic disorder at age 24 (N=47, 1.2%), by both self-report and interviewer-rated measures of psychotic experiences at age 18 (PPVs, 2.9% and 10.0%, respectively), was improved by incorporating information on frequency and distress (PPVs, 13.3% and 20.0%, respectively), although sensitivities were low. The PPV of an at-risk mental state at age 18 predicting incident disorder at ages 18-24 was 21.1% (95% CI=6.1, 45.6) (sensitivity, 14.3%, 95% CI=4.0, 32.7).

CONCLUSIONS

The study results show a peak in incidence of psychotic experiences during late adolescence as well as an unmet need for care in young people with psychotic disorders. Because of the low sensitivity, targeting individuals in non-help-seeking samples based only on more severe symptom cutoff thresholds will likely have little impact on population levels of first-episode psychosis.

Attentional focus moderates the relationship between attention to threat bias and delusion-like experiences in healthy adults

Background

The role of cognitive biases in delusion and delusion-like experiences has been widely investigated in recent years. However, little is known about individual differences, which may influence association between cognitive biases and formation of delusional beliefs. The aim of this study was to examine the moderating effect of self-reported attentional control on the relationship between attention to threat bias (ATB) and delusion-like experiences (DLEs) in healthy adults.

Methods

Participants (n = 138) completed the Davos Assessment of the Cognitive Biases Scale (DACOBS), the Attentional Control Scale (ACS) and the Peters et al. Delusions Inventory (PDI). The moderation analysis was performed to check the influence of different components of attentional control (i.e. general ability to allocate attention, focusing, shifting and divide attention) on the interplay between ATB and DLEs.

Results

The results supported the moderation model. Specifically, we found that a higher level of ability to focus attention is associated with a stronger effect of attention to threat bias on the overall frequency of DLEs. Our results indicate that ATB contributes to the number of DLEs only in individuals with high and moderate capacity to focus attention, whereas in those who scored low on the ACS focusing attention subscale, the presence of attentional bias does not influence the frequency of DLEs.

Conclusions

Our findings show that the individual difference variable, such as ability to voluntarily focus attention, may moderate the relationship between attention to threat bias and delusion-like experiences in healthy adults.

Adolescent psychosis risk symptoms predicting persistent psychiatric service use: A 7-year follow-up study

Background:

We investigated whether psychosis risk symptoms predicted psychiatric service use using seven-year register follow-up data.

Methods:

Our sample included 715 adolescents aged 15–18, referred to psychiatric care for the first time. Psychosis risk symptoms were assessed with the Prodromal Questionnaire (PQ) at the beginning of the treatment. We assessed the power of the overall PQ as well as its positive, negative, general, and disorganized psychosis risk symptom factors in predicting prolonged service use. Baseline psychiatric diagnoses (grouped into 7 categories) were controlled for. Based on both inpatient and outpatient psychiatric treatment after baseline, adolescents were divided into three groups of brief, intermittent, and persistent service use.

Results:

Stronger symptoms on any PQ factor as well as the presence of a mood disorder predicted prolonged service use. All of the PQ factors remained significant predictors when adjusted for baseline mood disorder and multimorbidity.

Conclusions:

In a prospective follow-up of a large sample using comprehensive mental health records, our findings indicate that assessing psychosis risk symptoms in clinical adolescent settings at the beginning of treatment could predict long-term need for care beyond diagnostic information. Our findings replicate the previous findings that positive psychosis risk symptoms are unspecific markers of severity of psychopathology. Also psychosis risk symptoms of the negative, disorganization, and general clusters are approximately as strongly associated with prolonged psychiatric service use in the upcoming years.

Lifetime and Momentary Psychotic Experiences in Adult Males and Females With an Autism Spectrum Disorder

BACKGROUND

Existing research shows that adults with an autism spectrum disorder (ASD) are more vulnerable to develop overt psychosis. However, studies investigating (subclinical) psychotic experiences (PE) in ASD are scarce, and it is unknown if PE are accompanied with more distress in adults with ASD compared to the general population. This study examined lifetime PE and accompanying distress, momentary PE levels, and the impact of daily life stress and negative affect (NA) on momentary PE in males and females with ASD compared to controls.

METHODS

In 50 adults with ASD (males N= 26, females N= 24) and 51 adults without ASD (males N= 26, females N= 25), the Community Assessment of Psychic Experiences (CAPE) was used to analyze group differences in frequency and distress of lifetime subclinical positive, negative, and depressive symptoms. The Experience Sampling Method (ESM) was used to measure momentary PE, NA, and stress (activity-related, event-related, and social stress) for 10 days. Multilevel analyses were conducted to test whether stress and NA were associated with momentary PE and whether these associations were modified by group or sex.

RESULTS

Adults with ASD reported more lifetime CAPE negative and depressive symptoms, but similar levels of PE, than controls. Higher levels of accompanying distress were found in participants with ASD for each subscale. With respect to ESM momentary PE, higher levels were reported by adults with ASD and a stronger association between event-related stress and momentary PE was found compared to controls. This was not the case for NA, activity-related, and social stress. Overall, no significant differences between male and female outcomes were found.

CONCLUSION

Adults with ASD are more prone to encounter lifetime subclinical negative and depressive symptoms and accompanying distress compared to adults without ASD. Similar levels of lifetime PE in both groups were still accompanied with more distress in the ASD group. Furthermore, higher levels of ESM momentary PE were found in participants with ASD. Additionally, event-related stress may act as a risk factor for PE in both females and males with ASD, with a stronger risk-increasing effect than in their control counterparts.

Prevalence and correlates of psychotic experiences in a nationally representative sample of Australian adolescents

OBJECTIVE

Despite growing literature on psychotic experiences, no nationally representative study has reported on the prevalence of both hallucinatory experiences and delusional experiences in Australian adolescents. Also, while many studies have examined the association between psychotic experiences and certain demographic and clinical correlates, there are more variables of interest to be investigated, including disordered eating behaviour and hours of sleep. The aims of this study were to examine (1) the prevalence of hallucinatory experiences and delusional experiences in Australian adolescents, and (2) the associations between different types of psychotic experiences with a broad range of demographic, clinical, and psychosocial variables.

METHODS

A random sample of Australian adolescents aged 14- to 17-year-olds were recruited in 2013-2014 as part of the Young Minds Matter Survey. Participants completed self-report questions regarding five different psychotic experience types (auditory and visual hallucinatory experiences, and thoughts read, special messages, spied upon) experienced in the past 12 months. Using logistic regression analyses, we investigated associations between psychotic experiences and demographic, clinical, and psychosocial factors.

RESULTS

The 12-month prevalence ranged from 3.3% (95% confidence interval = [2.6, 4.3]) for special messages to 14.0% (95% confidence interval = [12.3, 15.8]) for auditory hallucinatory experiences. At the bivariate level, each psychotic experience subtype was associated with increased likelihood of major depression, being bullied, psychological distress, low self-esteem, mental health service use and insufficient sleep (<8 hours per night). Multivariate analyses revealed both auditory and visual hallucinatory experiences were associated with an increased likelihood of four of these variables (depression, being bullied, service use, insufficient sleep), whereas associations with delusional experiences were inconsistent.

CONCLUSION

Hallucinatory and delusional experiences are common in Australian adolescents. Hallucinatory experiences, rather than delusional experiences, may be more clinically relevant in this demographic. When psychotic experiences are endorsed by adolescents, further assessment is indicated so as to ascertain more detail on the phenomenology of the experiences to better understand their clinical relevance.

Distress, Impairment and the Extended Psychosis Phenotype: A Network Analysis of Psychotic Experiences in an US General Population Sample

It has been proposed that subclinical psychotic experiences (PEs) may causally impact on each other over time and engage with one another in patterns of mutual reinforcement and feedback. This subclinical network of experiences in turn may facilitate the onset of psychotic disorder. PEs, however, are not inherently distressing, nor do they inevitably lead to impairment. The question arises therefore, whether nondistressing PEs, distressing PEs, or both, meaningfully inform an extended psychosis phenotype. The current study first aimed to exploit valuable ordinal data that captured the absence, occurrence and associated impairment of PEs in the general population to construct a general population based severity network of PEs. The study then aimed to partition the available ordinal data into 2 sets of binary data to test whether an occurrence network comprised of PE data denoting absence (coded 0) and occurrence/impairment (coded 1) was comparable to an impairment network comprised of binary PE data denoting absence/occurrence (coded 0) and impairment (coded 1). Networks were constructed using state-of-the-art regularized pairwise Markov Random Fields (PMRF). The severity network revealed strong interconnectivity between PEs and nodes denoting paranoia were among the most central in the network. The binary PMRF impairment network structure was similar to the occurrence network, however, the impairment network was characterized by significantly stronger PE interconnectivity. The findings may help researchers and clinicians to consider and determine how, when, and why an individual might transition from experiences that are nondistressing to experiences that are more commonly characteristic of psychosis symptomology in clinical settings.

Screening for sub-threshold psychotic experiences and perceived need for psychological services

AIM

Sub-threshold psychotic experiences (PEs) are common in the general population and may increase risk for psychological distress and psychosis onset, generating a need for effective community screening instruments. This study aimed to explore the utility of a brief, self-report, psychosis risk screening tool in predicting perceived need for psychological treatment among a non-clinical sample, above and beyond that accounted for by accompanying forms of psychopathology or trait neuroticism.

METHODS

Construct validity, predictive validity and test-retest reliability of the brief, self-report questionnaire for screening putative prepsychotic states were determined among college students (N = 679). Multiple linear regression analyses were conducted to explore the relationship between PEs and perceived need for psychological services.

RESULTS

With the exception of auditory perceptual disturbances, PEs were not significantly associated with one's need for services, or the belief from others that services are needed, after controlling for neuroticism, anxiety and depressive symptoms. Auditory perceptual disturbances were significantly associated with the perceived need for psychological services, even after accounting for these additional symptoms.

CONCLUSIONS

These results confirm the usefulness of the psychosis risk screening tool in evaluating the presence of sub-threshold PEs, particularly auditory perceptual disturbances. The relationship between other PEs and a perceived need for psychological services, however, was largely explained by the existence of neurotic traits and anxiety and depressive symptoms. Screening for auditory perceptual disturbances may be useful in identifying unmet clinical need among young adults.

Depression and anxiety mediate the relationship between temperament and character and psychotic-like experiences in healthy subjects

In this study we examined the hypothesis that depression and anxiety may mediate the relationship between personality traits and both positive and negative psychotic-like experiences (PLEs) in healthy adults. The Community Assessment of Psychic Experiences (CAPE) scale, Temperament and Character Inventory (TCI), Beck Depression Inventory (BDI) and State and Trait Anxiety Inventory (STAI) were administered to 492 healthy individuals. Multiple stepwise regression and mediation analyses were performed to examine whether depressive and anxiety symptoms influence the relationship between the TCI dimensions and positive and negative PLEs. Self-transcendence, persistence, novelty-seeking and self-directedness significantly predicted positive PLEs; self-directedness and harm avoidance were predictable for negative PLEs. Self-transcendence, self-directedness, persistence and harm avoidance also predicted the distress caused by positive PLEs, whereas self-directedness and harm avoidance predicted distress raised by negative PLEs. Depressive symptoms and the state of anxiety partially mediated the linkage between self-directedness and positive PLEs, and between self-directedness, harm avoidance and negative PLEs. Our findings confirm that the personality pattern influences both positive and negative PLEs as well as distress caused by experiencing positive and negative PLEs, and they indicate that certain personality traits may influence the development of PLEs via the emotional pathway of heightened depression and anxiety.

An n=1 Clinical Network Analysis of Symptoms and Treatment in Psychosis

INTRODUCTION

Dynamic relationships between the symptoms of psychosis can be shown in individual networks of psychopathology. In a single patient, data collected with the Experience Sampling Method (ESM-a method to construct intensive time series of experience and context) can be used to study lagged associations between symptoms in relation to illness severity and pharmacological treatment.

METHOD

The patient completed, over the course of 1 year, for 4 days per week, 10 daily assessments scheduled randomly between 10 minutes and 3 hours apart. Five a priori selected symptoms were analysed: 'hearing voices', 'down', 'relaxed', 'paranoia' and 'loss of control'. Regression analysis was performed including current level of one symptom as the dependent variable and all symptoms at the previous assessment (lag) as the independent variables. Resulting regression coefficients were printed in graphs representing a network of symptoms. Network graphs were generated for different levels of severity: stable, impending relapse and full relapse.

RESULTS

ESM data showed that symptoms varied intensely from moment to moment. Network representations showed meaningful relations between symptoms, e.g. 'down' and 'paranoia' fuelling each other, and 'paranoia' negatively impacting 'relaxed'. During relapse, symptom levels as well as the level of clustering between symptoms markedly increased, indicating qualitative changes in the network. While 'hearing voices' was the most prominent symptom subjectively, the data suggested that a strategic focus on 'paranoia', as the most central symptom, had the potential to bring about changes affecting the whole network.

CONCLUSION

Construction of intensive ESM time series in a single patient is feasible and informative, particularly if represented as a network, showing both quantitative and qualitative changes as a function of relapse.

The association between childhood autistic traits and adolescent psychotic experiences is explained by general neuropsychiatric problems

Studies suggest associations between childhood autistic traits and adolescent psychotic experiences. However, recent research suggests that a general neuropsychiatric problems factor predicts adverse outcomes better than specific diagnostic entities. To examine if the alleged association between autistic traits and psychotic experiences could rather be explained by a general neuropsychiatric problems factor comprising symptoms of ADHD, tic disorder, developmental coordination disorder, and learning disorder, we conducted a prospective cohort study based on the Child and Adolescent Twin Study in Sweden. In addition, we examined the genetic and environmental influences on the associations. A total of 9,282 twins with data on childhood autistic traits and other neuropsychiatric problems, and follow-up data on psychotic experiences at ages 15 and/or 18 years were included. First, psychotic experiences were regressed on autistic traits and second, the general neuropsychiatric problems factor was added to the model. Auditory hallucinations were analyzed separately from the other psychotic experiences. Finally, twin analyses were employed to disentangle genetic from environmental influences in the observed associations. Replicating prior research, significant associations were found between autistic traits in childhood and auditory hallucinations at ages 15 and 18. However, after controlling for the general neuropsychiatric problems factor, the associations between autistic traits and auditory hallucinations disappeared, whereas the association between the general neuropsychiatric problems factor and auditory hallucinations persisted after controlling for autistic traits. Twin analyses revealed that the association between the general neuropsychiatric problems factor and auditory hallucinations was driven by shared genetic influences. © 2015 Wiley Periodicals, Inc.

Social and clinical correlates of the persistence of psychotic experiences in the general population

Recent epidemiological evidence suggests that sub-threshold psychotic experiences commonly occur in the general population. When these experiences persist over time, they may increase risk for psychotic disorder or lead to other clinical or functional impairments. The aims of this study were to distinguish the relative importance of sociodemographic factors and clinical factors, including characteristics of the psychotic experiences themselves, in determining the course of psychotic symptoms over time. Participants were drawn from the Collaborative Psychiatric Epidemiology Surveys. We tested for retrospectively-reported predictors of current psychotic experiences among individuals who reported lifetime psychotic experiences, with onset prior to the past year (n=921), using logistic regression. Persistence was primarily related to demographic variables, with lower odds associated with being married and having at least a college education. Individuals reporting prior to the past year auditory hallucinations were more likely to have persistent psychotic experiences than those reporting other types of psychotic experiences. Interventions aiming at strengthening family support and social skills may reduce the likelihood of persistence among individuals with psychotic experiences, thereby reducing risk for psychotic disorders and other related outcomes. Future studies should continue to identify predictors of persistence versus remission and further explore clinical services for those with persistent psychotic experiences.

Psychotic Experiences, Working Memory, and the Developing Brain: A Multimodal Neuroimaging Study

Psychotic experiences (PEs) occur in the general population, especially in children and adolescents, and are associated with poor psychosocial outcomes, impaired cognition, and increased risk of transition to psychosis. It is unknown how the presence and persistence of PEs during early adulthood affects cognition and brain function. The current study assessed working memory as well as brain function and structure in 149 individuals, with and without PEs, drawn from a population cohort. Observer-rated PEs were classified as persistent or transient on the basis of longitudinal assessments. Working memory was assessed using the n-back task during fMRI. Dynamic causal modeling (DCM) was used to characterize frontoparietal network configuration and voxel-based morphometry was utilized to examine gray matter. Those with persistent, but not transient, PEs performed worse on the n-back task, compared with controls, yet showed no significant differences in regional brain activation or brain structure. DCM analyses revealed greater emphasis on frontal connectivity within a frontoparietal network in those with PEs compared with controls. We propose that these findings portray an altered configuration of working memory function in the brain, potentially indicative of an adaptive response to atypical development associated with the manifestation of PEs.

Screening for psychotic experiences: social desirability biases in a non-clinical sample

AIM

Subthreshold psychotic experiences are common in the population and may be clinically significant. Reporting of psychotic experiences through self-report screens may be subject to threats to validity, including social desirability biases. This study examines the influence of social desirability on the reporting of psychotic experiences.

METHODS

College students (n = 686) completed a psychosis screen and the Marlowe-Crowne social desirability scale as part of a self-report survey battery. Associations between psychosis and social desirability were tested using logistic regression models.

RESULTS

With the exception of auditory hallucinations, all other measures of psychotic experiences were subject to social desirability biases. Respondents who gave more socially desirable answers were less likely to report psychotic experiences.

CONCLUSIONS

Respondent's tendency to underreport psychotic experiences should be accounted for when screening for these symptoms clinically. Findings also suggest that population figures based on self-report may underestimate the prevalence of subthreshold delusions but not hallucinations.

Internal structure of the Community Assessment of Psychic Experiences-Positive (CAPE-P15) scale: Evidence for a general factor

BACKGROUND

Psychotic-like experiences (PLEs) are prevalent in the general population and are associated with poor mental health and a higher risk of psychiatric disorders. The Community Assessment of Psychic Experiences-Positive (CAPE-P15) scale is a self-screening questionnaire to address subclinical positive psychotic symptoms (PPEs) in community contexts. Although its psychometric properties seem to be adequate to screen PLEs, further research is needed to evaluate certain validity aspects, particularly its internal structure and its functioning in different populations.

AIM

To uncover the optimal factor structure of the CAPE-P15 scale in adolescents aged 13 to 18 years using factorial analysis methods suitable to manage categorical variables.

METHOD

A sample of 727 students from six secondary public schools and 245 university students completed the CAPE-P15. The dimensionality of the CAPE-P15 was tested through exploratory structural equation models (ESEMs). Based on the ESEM results, we conducted a confirmatory factor analysis (CFA) to contrast two factorial structures that potentially underlie the symptoms described by the scale: a) three correlated factors and b) a hierarchical model composed of a general PLE factor plus three specific factors (persecutory ideation, bizarre experiences, and perceptual abnormalities).

RESULTS

The underlying structure of PLEs assessed by the CAPE-P15 is consistent with both multidimensional and hierarchical solutions. However, the latter show the best fit. Our findings reveal the existence of a strong general factor underlying scale scores. Compared with the specific factors, the general factor explains most of the common variance observed in subjects' responses.

CONCLUSIONS

The findings suggest that the factor structure of subthreshold psychotic experiences addressed by the CAPE-P15 can be adequately represented by a general factor and three separable specific traits, supporting the hypothesis according to which there might be a common source underlying PLEs.

Relationships of perceived public stigma of mental illness and psychosis-like experiences in a non-clinical population sample

PURPOSE

Studies on the association between psychopathology, perceived public stigma, and labeling in mental illness have focused primarily on severe but rare mental disorders, especially schizophrenia, or other clinically defined psychotic disorders. Although evidence is mounting that psychosis-like experiences show high prevalence in the general population and lead to an increased risk of psychotic disorders, little is known about how psychosis-like experiences independently affect perceived public stigma in the non-clinical population. The aim of the present study was to examine the relationship between psychosis-like experiences and perceived public stigma in a non-clinical sample.

METHODS

For this cross-sectional study, we recruited 524 individuals (239 male, 285 female) who had no lifetime history of psychiatric disorder. Participants completed questionnaires that asked for sociodemographic and clinical information, a measure of perceived public stigma (Perceived Psychiatric Stigma Scale [PPSS]), and two measures of psychosis-like experiences (Peters et al. Delusions Inventory [PDI]; Cardiff Anomalous Perceptions Scale [CAPS]).

RESULTS

Of the sociodemographic characteristics analyzed in this study-gender, age, education level, marital status, and religion-only age simultaneously influenced PPSS, PDI, and CAPS scores. As hypothesized, perceived public stigma was positively correlated with measures of psychosis-like experiences, even after controlling for age. Furthermore, the perceived stigma was more strongly associated with delusion proneness than with anomalous perceptual experiences.

CONCLUSION

The association between psychopathology and perceived public stigma appears to extend beyond clinically defined psychosis to more common psychosis-like experiences in a sample drawn from the general Han Chinese population.

Treatment seeking and unmet need for care among persons reporting psychosis-like experiences

OBJECTIVE

Psychosis-like experiences may be clinically significant given their demonstrated associations with concurrent psychological distress and the later development of diagnosable psychotic disorders. Prior studies of treatment for psychosis-like experiences have yielded conflicting results. The aims of this study were to investigate help seeking and need for care among individuals with psychosis-like experiences in a large general population sample.

METHODS

Data from the Collaborative Psychiatric Epidemiology Surveys (N=10,541) were used to examine help-seeking behaviors among survey respondents who reported psychosis-like symptoms over a 12-month period. Adjusted odds ratios were calculated for a variety of help-seeking variables, with control for demographic factors and co-occurring psychiatric conditions.

RESULTS

Among the 10,541 respondents, 3.4% reported a psychosis-like experience in the past 12 months. Respondents who reported psychosis-like experiences were more than twice as likely as those who did not to seek treatment. Those who reported such experiences but who did not seek treatment were more likely to have felt the need for or to have been encouraged by others to seek treatment and less likely to have felt that they had no psychiatric problem. Associations with unmet need for care were largely attributable to co-occurring psychiatric disorders.

CONCLUSIONS

Respondents with psychosis-like experiences had elevated rates of help seeking, as well as significant unmet clinical need among those not in treatment.

Predictors of distress associated with psychotic-like anomalous experiences in clinical and non-clinical populations

OBJECTIVES

Psychotic-like anomalous experiences are not inherently distressing, nor do they inevitably lead to clinical conditions. However, distress is an important predictor of onset and relapse in psychosis, and a primary indicator of problematic mental health. This study aimed to identify factors that predict distress across three groups with anomalous experiences.

DESIGN AND METHODS

This study used a cross-sectional design. Participants in 'Diagnosed' (n = 35), 'At Risk' (n = 20), and 'Undiagnosed' (n = 36) groups completed the Appraisals of Anomalous Experiences Interview (AANEX; Brett et al., 2007, Br. J. Psychiatry, 191, s23), which taps anomalies experienced, appraisals, and other psychological and contextual variables. A series of ordinal logistic regression analyses was conducted to investigate which variables predicted anomaly-related distress.

RESULTS

Predictors of higher distress were anomalous states characterized by changes in awareness and cognitive functioning (rather than more typical positive symptoms), appraisals of experiences as caused by 'other people', and greater attempted control over experiences. Predictors of lower distress were 'spiritual' appraisals, greater perceived social support/understanding, greater perceived controllability, and reacting with a 'neutral response'.

CONCLUSIONS

While psychotic-like experiences themselves are not necessarily distressing, appraisals and responses to anomalies do predict distress, as do factors relating to the social context. This adds support to the cognitive-behavioural models, and continuum models, of positive psychotic symptoms.

An updated and conservative systematic review and meta-analysis of epidemiological evidence on psychotic experiences in children and adults: on the pathway from proneness to persistence to dimensional expression across mental disorders

BACKGROUND

The psychosis-proneness-persistence-impairment model of psychotic disorder incorporates notions of both phenomenological and temporal continuity (persistence) of psychotic experiences (PE), but not structural continuity. Specific testable propositions of phenomenological continuity and persistence are identified. Method Propositions are tested by systematic reviews of the epidemiology of PE, persistence of PE and disorder outcomes, and meta-analyses (including Monte Carlo permutation sampling, MCPS) of reported rates and odds ratios (ORs).

RESULTS

Estimates of the incidence and prevalence of PE obtained from 61 cohorts revealed a median annual incidence of 2.5% and a prevalence of 7.2%. Meta-analysis of risk factors identified age, minority or migrant status, income, education, employment, marital status, alcohol use, cannabis use, stress, urbanicity and family history of mental illness as important predictors of PE. The mode of assessment accounted for significant variance in the observed rates. Across cohorts, the probability of persistence was very strongly related to the rate of PE at baseline. Of those who report PE, ∼20% go on to experience persistent PE whereas for ∼80%, PE remit over time. Of those with baseline PE, 7.4% develop a psychotic disorder outcome.

CONCLUSIONS

Compelling support is found for the phenomenological and temporal continuity between PE and psychotic disorder and for the fundamental proposition that this relationship is probabilistic. However, imprecision in epidemiological research design, measurement limitations and the epiphenomenological nature of PE invite further robust scrutiny of the continuity theory.

Assessing anomalous perceptual experiences in nonpsychiatric individuals and outpatients with psychosis in Taiwan: an investigation using the cardiff anomalous perceptions scale (CAPS)

The Cardiff anomalous perceptions scale (CAPS) has been recently designed for the assessment of anomalous perceptual experiences in the general population, and includes dimensions that measure distress, intrusiveness, and frequency. The purpose of this study was to assess the psychometric properties of a Taiwanese version of the CAPS. The English version of the CAPS was translated into Taiwanese (CAPS-T) and the latter was applied to this study. We administered the questionnaire to a consecutive sample of 192 participants with (n = 106; clinical group including schizophrenia and affective psychosis) or without psychotic disorders (n = 86; non-clinical group). In addition to the CAPS-T, the Taiwanese version of the brief psychiatric symptom rating scale (BSRS) measured the severity of the psychopathology. We also tested the psychometric properties of the CAPS-T including construct validity, internal consistency, test-retest reliability, and convergent and discriminative validity. Overall, the CAPS-T showed good construct validity, internal consistency, and stability over time and correlated significantly with the psychoticism subscale of the BSRS. As predicted, the mean differences in CAPS-T scores between participants with or without a psychotic disorder were significant. Convergent and discriminative validity were satisfactory. A score of 5 was found to the best threshold in discriminating between clinical and non-clinical samples. Our findings indicate that the Taiwanese version of the CAPS is a reliable and valid instrument to measure the multidimensionality of perceptual anomalies in general and appears to complement the clinical measures of psychosis proneness in Taiwan.

Preoccupation and distress are relevant dimensions in delusional beliefs

BACKGROUND AND PURPOSE

A large number of subjective experiences and beliefs with some degree of affinity with psychotic symptoms can be found in the general population. However, the appraisal of these psychotic-like experiences in terms of associated distress, raised preoccupation, and the conviction with which the experience is held can be more discriminative in distinguishing people in need for care from those who simply hold unusual or uncommon beliefs because of cultural reasons.

METHOD

In this study, 81 patients with a Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, diagnosis of schizophrenia or an affective disorder with psychotic features were compared on the Peters et al Delusions Inventory (PDI) to 210 people from the same local area, who had never received a formal diagnosis of a mental disorder.

RESULTS

Patients scored higher than controls on the PDI total score and on its distress, preoccupation, and conviction subscales. A stepwise logistic regression model showed PDI-preoccupation (odds ratio, 2.46; 95% confidence interval, 1.52-3.98) and, marginally, PDI-distress (odds ratio = 1.58; 95% confidence interval, 0.93-2.58) adding discriminative power to PDI total score in distinguishing patients from controls.

CONCLUSIONS

The evaluation of the severity of delusion-like experiences and beliefs is important in discriminating patients diagnosed with psychosis from people who are not in need of care.

The psychometric properties of the Peters et al. delusions inventory (PDI) in Taiwan: reliability, validity, and utility

PURPOSE

The Peters et al. Delusions Inventory (PDI) is a commonly used instrument to measure delusion proneness in the general population and includes dimensions that measure distress, preoccupation, and conviction of unusual beliefs. This self-report scale has already been translated into several languages. However, there has not been a validated Taiwanese version previously reported. The aims of the present study were to translate and test the cross-cultural reliability and validity of the PDI in Taiwanese as well as to establish its sensitivity, specificity, and discriminative validity.

METHODS

We administered the questionnaire to a consecutive sample of 253 participants with (n = 154; clinical group including schizophrenia and affective psychosis) or without psychotic disorders (n = 99; non-clinical group). In addition to the Taiwanese version of the PDI (PDI-T), the Taiwanese version of the Brief Psychiatric Symptom Rating Scale (BSRS) was used to measure the severity of psychopathology. We tested the psychometric properties of the PDI-T, including its construct validity, internal consistency, test-retest reliability, concurrent, and discriminative validity.

RESULTS

Overall, the PDI-T showed good construct validity, internal consistency, and stability over time, and it was significantly correlated with the BSRS subscales of psychotic symptoms. The convergent and discriminative validity was satisfactory. The area under the receiver operating characteristic curve of the PDI-T was 0.752. This research found that the most appropriate PDI-T yes/no cut-off scores for determining the absence and presence of delusion proneness were 5 and 13.

CONCLUSIONS

The PDI is a reliable and valid instrument for measuring the dimensionality of delusion proneness and appears to complement subclinical psychosis assessment scales for both epidemiological and clinical research in Taiwan.

Evidence for a persistent, environment-dependent and deteriorating subtype of subclinical psychotic experiences: a 6-year longitudinal general population study

BACKGROUND

Research suggests that subclinical psychotic experiences during adolescence represent the behavioral expression of liability for psychosis. Little is known, however, about the longitudinal trajectory of liability in general population samples.

METHOD

Growth mixture modeling was used to examine longitudinal trajectories of self-reported positive psychotic experiences in the Youth Self Report (YSR), completed three times over a period of 6 years by a general population cohort of adolescents aged 10-11 years at baseline (n=2230).

RESULTS

Four groups with distinct developmental trajectories of low, decreasing, increasing and persistent levels of mild positive psychotic experiences were revealed. The persistent trajectory was associated strongly with cannabis use, childhood trauma, developmental problems and ethnic minority status, and consistently displayed strong associations with factors known to predict transition from subclinical psychotic experience to clinical psychotic disorder (severity of and secondary distress due to psychotic experiences, social and attentional problems and affective dysregulation) and also with high levels of parental-reported psychotic experiences and use of mental health care at the end of the follow-up period. Progressively weaker associations were found for the increasing, decreasing and low trajectories respectively.

CONCLUSIONS

The results suggest that the outcome of early developmental deviation associated with later expression of psychotic experiences is contingent on the degree of later interaction with environmental risks inducing, first, persistence of psychotic experiences and, second, progression to onset of need for care and service use. Insight into the longitudinal dynamics of risk states in representative samples may contribute to the development of targeted early intervention in psychosis.

Lack of association between psychosis-like experiences and seeking help from professionals: a case-controlled study

BACKGROUNDS

It still remains unclear whether individuals who experience attenuated psychotic symptoms are likely to seek help, whereas depressive symptoms are more likely to be associated with help-seeking behavior than these symptoms themselves. The aims of our study were to compare the profile of these symptoms between clinical and community samples and to investigate to what extent help-seeking behavior depends on the severity of psychosis-like symptoms and/or depressive symptoms.

METHODS

The clinical sample consisted of help-seeking outpatients aged 16-30 years who had approached a community mental health clinic (N=750, mean age: 23.3±4.2 years, 62.4% females). The community sample was comprised of students from two universities and two high schools (N=781, mean age: 18.1±1.7 years, 59.2% females). Psychosis-like experiences were assessed using the PRIME Screen-Revised (PS-R), a self-reported screening instrument for assessing the risk of psychosis. Depressive symptoms were assessed using the Zung Self-rating Depression Scale (ZSDS), a 20-item self-reported questionnaire.

RESULTS

Among the clinical and community samples, 27% and 10% had positive PS-R results respectively. No significant difference in the PS-R total score or the frequency of PS-R-positive items was observed between the clinical and community samples. A logistic regression analysis revealed that none of the psychosis-like experiences were significantly associated with help-seeking behavior, after controlling for the effect of depressive symptoms.

CONCLUSIONS

Our findings showed that attenuated psychotic symptoms do not contribute significantly to help-seeking behavior, suggesting that the relationships among PLEs, depressive symptoms, and help-seeking behavior should be reconsidered.

WITHDRAWN: The psychometric properties of the Taiwanese version of the Cardiff Anomalous Perceptions Scale

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The structure of the extended psychosis phenotype in early adolescence--a cross-sample replication

The extended psychosis phenotype, or the expression of nonclinical positive psychotic experiences, is already prevalent in adolescence and has a dose-response risk relationship with later psychotic disorder. In 2 large adolescent general population samples (n = 5422 and n = 2230), prevalence and structure of the extended psychosis phenotype was investigated. Positive psychotic experiences, broadly defined, were reported by the majority of adolescents. Exploratory analysis with Structural Equation Modelling (Exploratory Factor Analysis followed by Confirmatory Factor Analysis [CFA]) in sample 1 suggested that psychotic experiences were best represented by 5 underlying dimensions; CFA in sample 2 provided a replication of this model. Dimensions were labeled Hallucinations, Delusions, Paranoia, Grandiosity, and Paranormal beliefs. Prevalences differed strongly, Hallucinations having the lowest and Paranoia having the highest rates. Girls reported more experiences on all dimensions, except Grandiosity, and from age 12 to 16 years rates increased. Hallucinations, Delusions, and Paranoia, but not Grandiosity and Paranormal beliefs, were associated with distress and general measures of psychopathology. Thus, only some of the dimensions of the extended psychosis phenotype in young people may represent a continuum with more severe psychopathology and predict later psychiatric disorder.

A twin study of genetic and environmental determinants of abnormal persistence of psychotic experiences in young adulthood

Evidence suggests that subclinical psychotic experiences are more likely to cause transition to psychotic disorder if their expression becomes persistent. The study of longitudinal patterns of subclinical psychotic experiences may help to distinguish subgroups with transient and persistent psychotic symptoms, who may differ in risk of later psychosis. The current study investigated patterns of developmental course of subclinical psychotic experiences in a general population sample of 566 female twins, aged 18-45 years. The positive symptoms subscale of the Community Assessment of Psychic Experiences (CAPE), completed three times in 2 years, was analyzed with growth modeling. Using Latent Class Analysis, two developmental courses were distinguished: a Persistent and a Low (expression of subclinical psychotic experiences) group. The Persistent group reported significantly higher levels of depressive and negative symptoms and worse functioning in daily life. Childhood trauma (OR: 3.26, P < 0.0001) and stressful life events over the study period (OR: 3.15, P = 0.031) predicted membership of the Persistent group. Of the monozygotic (MZ) twins with their co-twin in the Persistent group, 49% also were in the Persistent group themselves (OR: 9.32, P < 0.0001), compared to only 14% in the dizygotic (DZ) co-twins (OR: 1.56, P = 0.42) (χ(2)(2) = 22.97; P < 0.001). The findings suggest that persistence of subclinical psychosis is influenced by both genetic and environmental factors, providing the possibility to study the (possibly modifiable) etiology underlying the longitudinal process of persistence of the early expression of psychosis liability.

The Self-screen-Prodrome as a short screening tool for pre-psychotic states

BACKGROUND

Early detection of psychosis is an important issue in current research. Early intervention helps to improve the outcome of the disorder. Therefore, a comprehensive examination in large populations, necessary as it might be, is economically almost not feasible. A screening via self-report is more practicable as it helps focus on individuals with high symptom loads.

AIM

To examine aspects of validity of the Self-screen-Prodrome (SPro) as a new screening tool for prodromal states of psychosis in a military sample.

METHOD

938 Swiss conscripts were assessed with the SPro, the Eppendorf Schizophrenia-Inventory (ESI) and the Symptom-Checklist-90-Revised (SCL-90-R). Conscripts with potential psychosis-like pathology (T-transformed Severity Index of the SCL-90-R-subscales Psychoticism [PSYC] and Paranoid Ideation [PARA]≥63) were compared with those not meeting the criteria of this condition (non-cases).

RESULTS

Both groups (cases and non-cases) showed significant differences in their mean scores on SPro and ESI, although only the SPro had satisfactory effect sizes. In hierarchic logistic regression models the SPro turned out to be highly predictive for caseness while ESI-scales were not significant. A cut-off score of ≥2 on the SPro subscale for psychotic risk (SPro-Psy-Risk) was found to identify caseness best with a sensitivity of 74% and a specificity of 61%.

CONCLUSION

The SPro has proven to be a valid and very economic screening tool for general and prodromal pathology in large populations.

Hearing voices in a non-psychiatric population

BACKGROUND

Many people hear voices but do not access psychiatric services and their experiences are largely unknown, not least because of the difficulty in contacting such people. This study investigates the beliefs held about voices, distress experienced, and provides a topographical account of the experience of hearing voices in a sample of individuals who hear voices in a non-psychiatric population.

METHOD

A quantitative questionnaire internet-based study with a within-subjects and between-subjects design was used. The internet was used to make contact with people who hear voices. One hundred and eighty-four participants in the general population who heard voices completed measures online assessing anxiety, depression, and beliefs about their dominant voice.

RESULTS

Participants reported a broad range of experiences associated with hearing voices, some in keeping with the previous research on clinical populations.

CONCLUSION

The use of the internet to recruit and research non-clinical samples of people who hear voices is supported. This study provides details regarding demographic information and the experience of voice hearing from a fairly large sample of people who hear voices in a non-psychiatric population. It lends support to the idea that voice hearing occurs on a continuum, with evidence that many people hear voices in the general population and are not distressed by the experience.

Hallucinations in nonpsychotic disorders: toward a differential diagnosis of "hearing voices"

While auditory hallucinations (AH) are prototypic psychotic symptoms whose clinical presence is often equated with a psychotic disorder, they are commonly found among those without mental illness as well as those with nonpsychotic disorders not typically associated with hallucinations in DSM-IV. This incongruity presents a significant challenge for clinical work and efforts to revise the next iteration of the DSM. Auditory hallucinations found among "normal" people suggest that either AH are not as pathologic as they are typically taken to be, or that less-than-hallucinatory experiences are routinely mischaracterized as AH. Such hallucinations in the context of conversion disorder, trauma, sensory deprivation, and certain cultural settings strengthen an association between AH and psychopathology but suggest limited diagnostic specificity and relevance. It may be useful to think of AH like coughs-common experiences that are often, but not always, symptoms of pathology associated with a larger illness. Although these issues have been known for many years, they are rarely discussed in American psychiatry and need to be addressed in future research and clinical work.

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

A systematic review of all reported incidence and prevalence studies of population rates of subclinical psychotic experiences reveals a median prevalence rate of around 5% and a median incidence rate of around 3%. A meta-analysis of risk factors reveals associations with developmental stage, child and adult social adversity, psychoactive drug use, and also male sex and migrant status. The small difference between prevalence and incidence rates, together with data from follow-up studies, indicates that approximately 75-90% of developmental psychotic experiences are transitory and disappear over time. There is evidence, however, that transitory developmental expression of psychosis (psychosis proneness) may become abnormally persistent (persistence) and subsequently clinically relevant (impairment), depending on the degree of environmental risk the person is additionally exposed to. The psychosis proneness-persistence-impairment model considers genetic background factors impacting on a broadly distributed and transitory population expression of psychosis during development, poor prognosis of which, in terms of persistence and clinical need, is predicted by environmental exposure interacting with genetic risk.

Psychotic-like experiences in a community sample of adolescents: implications for the continuum model of psychosis and prediction of schizophrenia

OBJECTIVE

Studies conducted in community samples suggest that psychotic-like experiences are common in the general population, leading to suggestions that they are either variations of normal personality or are different expressions of underlying vulnerability to psychotic disorder. Different types of psychotic symptoms may exist, some being normal variants and some having implications for mental health and functioning. The aim of the present study was to determine if different subtypes of psychotic-like experiences could be identified in a community sample of adolescents and to investigate if particular subtypes were more likely to be associated with psychosocial difficulties, that is, distress, depression and poor functioning, than other subtypes.

METHOD

Eight hundred and seventy-five Year 10 students from 34 schools participated in a cross-sectional survey that measured psychotic-like experiences using the Community Assessment of Psychic Experiences; depression using the Centre for Epidemiologic Studies Depression Scale; and psychosocial functioning using the Revised Multidimensional Assessment of Functioning Scale. Factor analysis was conducted to identify any subtypes of psychotic experiences.

RESULTS

Four subtypes of psychotic-like experiences were identified: Bizarre Experiences, Perceptual Abnormalities, Persecutory Ideas, and Magical Thinking. Intermittent, infrequent psychotic experiences were common, but frequent experiences were not. Bizarre Experiences, Perceptual Abnormalities and Persecutory Ideas were strongly associated with distress, depression and poor functioning. Magical Thinking was only weakly associated with these variables. Overall these findings may suggest that infrequent psychotic-like experiences are unlikely to be a specific risk factor for onset of a psychotic disorder in community samples.

CONCLUSIONS

Given that the different subtypes had varying associations with current difficulties it is suggested that not all subtypes confer the same risk for onset of psychotic disorder and poor outcome. Bizarre Experiences, Perceptual Abnormalities and Persecutory Ideas may represent expressions of underlying vulnerability to psychotic disorder, but Magical Thinking may be a normal personality variant.

Measuring psychosis proneness in a nonclinical Korean population: is the Peters et al Delusions Inventory useful for assessing high-risk individuals?

OBJECTIVES

We examined the psychometric properties of the Korean version of the Peters et al Delusions Inventory (PDI) 40 and investigated the distribution of delusional ideation in a nonclinical population. We also used the item response theory to evaluate the usefulness of the PDI in measuring the risk for psychosis.

METHODS

A total of 310 nonclinical individuals completed the Korean PDI-40, the Magical Ideation Scale (MIS), and the Schizotypal Personality Scale (STA). In addition, 60 psychotic inpatients with delusions completed the PDI-40. Among 310 individuals, 124 participated in a follow-up study 6 months after completing their original questionnaire.

RESULTS

The PDI-40 revealed a slightly skewed distribution, but the score range was similar to that of the British population. Scores were negatively correlated with age, but no sex differences were found. The Korean PDI-40 exhibited good internal consistency and test-retest reliability. The PDI was significantly correlated with the MIS and the STA. Ten components were extracted through a principal component analysis with varimax rotation. The test results using item response theory revealed 39 items as the items which individuals with very high level of psychosis proneness will answer as "yes." Moreover, all items yielded "above moderate" discrimination in terms of psychosis proneness.

CONCLUSIONS

We confirmed the reliability and validity of the Korean PDI-40. The usefulness of the PDI-40 in a nonclinical population was replicated in the Korean sample. The PDI-40 can be used as an informative device when investigating "psychosis proneness" in a group at high risk for psychosis.

Dissociating the components of inhibitory control involved in predisposition to hallucinations

INTRODUCTION

We have previously linked hallucinations in schizophrenia and hallucination predisposition to poor intentional inhibition. However, these previous studies have not systematically investigated the separable dimensions of inhibitory control involved, namely, intentional versus unintentional, and inhibition versus resistance to interference. The aim of this study was to clarify the critical component(s) of inhibitory control specifically related to hallucination predisposition.

METHODS

The Launay-Slade Hallucination Scale-Revised (LSHS-R) was completed by 589 undergraduate students, from which high- (n=28) and low- (n=25) hallucination predisposition groups were drawn. Participants were administered tasks measuring unintentional inhibition (Brown-Peterson variant task) and intentional resistance to interference (directed ignoring [DI] task).

RESULTS

The high LSHS-R group showed significant difficulties relative to the low LSHS-R group on the DI task only; although these differences did not remain significant when controlling for anxiety or delusional thinking. Regression analyses showed that anxiety, but not delusional thinking, independently contributed to variance in DI task performance above that accounted for by hallucination predisposition.

CONCLUSIONS

Intentional rather than unintentional control of intrusive cognitions appears to play an important role in hallucination predisposition. The results indicate that difficulties with the intentional resistance to interference from concurrent external distractors may be a common mechanism underlying positive schizophrenia symptoms and anxiety. However, given previous findings reported by Paulik, Badcock, and Maybery (2007), we propose that hallucination predisposition is also characterised by a difficulty with the active suppression of intrusive cognitions - that is, intentional inhibition - which is not shared with anxiety or delusional symptoms.

Significance of cognitive intervention for voice hearers

PURPOSE

Studies show that focused intervention attenuates depreciatory hallucinations.

DESIGN AND METHODS

A repeated measures design was used in this randomized controlled trial to determine the significance of any sustained abatement in the hallucinations of 65 persons suffering from schizophrenia.

FINDINGS

Participants exposed to usual care supplemented with cognitive nursing intervention reported less severe hallucinations 1 year following treatment than did participants exposed to usual care only. They were 13.7 times more likely to maintain a 3-point drop in their hallucination scores.

PRACTICE IMPLICATIONS

It appears that the hallucinations of 1 in every 2.7 persons with schizophrenia will abate significantly with cognitive intervention.

Accuracy of nurses' perceptions of voice hearing and psychiatric symptoms

AIM

This article reports a study of nurses' assessments of a voice hearer's voices and psychiatric symptoms, and associations of these perceptions with nurses' education, career experience and primary care role.

BACKGROUND

Traditional views in nursing suggest that to engage voice hearers in a discussion of their voices is to support the psychopathology of the voice hearers. Research into how voice hearers conceptualize voice hearing has generated a range of perspectives, raising concerns about whether nurses capture sufficient, accurate and specific assessment data about the experiences of voice hearers.

METHOD

One hundred and fifteen psychiatric nurses rated items on an Inventory of Voice Experiences and the Brief Psychiatric Rating Scale while viewing a videotaped assessment of a voice hearer with serious and persistent mental illness. The voice hearer in the videotape used the same instruments to rate his own voices and symptoms. This self-assessment was undertaken 30 days before and immediately before production of the video-recorded assessment. The data were collected between 2000 and 2002.

RESULTS

The voice hearer's ratings of his voice hearing experiences and psychiatric symptoms were consistent over a 30-day period. Most nurse ratings of the voice hearer's voices and psychiatric symptoms did not match those of the voice hearer. However, the voice hearer and nurses demonstrated a moderately positive association between the voice hearer's voices and symptoms. Ratings of graduate-educated case managers and clinical nurse specialists (n=30) in clinical practice settings were more consistent with one another and corresponded more closely with the ratings of the voice hearer, particularly for the association between the voice hearer's voices and symptoms.

CONCLUSION

Accurate and specific assessment of voice hearing may facilitate engagement with voice hearers and improve the selection of strategies to help them manage the voices that upset them.

Association between psychotic experiences and depression in a clinical sample over 6 months

Psychotic-like experiences (PLEs) are used to identify individuals considered to be at Ultra High Risk (UHR) of, or prodromal for, psychotic disorder. They are also common in the general population and in clinical samples of non-psychotic individuals. Depression has been found to be an important factor in mediating outcome in those with PLEs in both community and UHR populations. It is associated with increased risk of transition to psychotic disorder in the UHR group, and with need for care in relation to PLEs in community samples. In this study we aimed to examine the 6-month outcome of PLEs in a sample of help-seeking young people aged 15 to 24 years in relation to their level of depression. Subjects (n=140) were assessed at baseline and 6 months for PLEs and depression. PLEs were measured by the Community Assessment of Psychic Experiences (CAPE). Depression was assessed as a continuous measure using the Mood and Anxiety Symptom Questionnaire (MASQ) and categorically according to DSM-IV diagnosis of mood disorder. PLEs reduced in conjunction with an improvement in depression level and with remission of diagnosis of mood disorder. It is important to assess depression in those with PLEs and consider the need for treatment of the comorbid depressive syndrome. This may reduce the risk of worsening of PLEs and transition to psychotic disorder.