The Latent Structure of Negative Symptoms in the General Population in Adolescence and Emerging Adulthood

The Role of Negative Symptoms on the Continuum of Psychosis Risk as a Mediator of the Relationship Between Personality and Functioning in Individuals With Psychotic-Like Experiences

AIM

Psychotic-like experiences (PLEs) may increase the risk of psychosis. Most of the research on PLEs focuses on their positive dimension-for example, hallucinatory-like experiences or delusion-like thoughts. Relatively little is known about the role of PLEs on the continuum of negative symptoms. The aim of this study was to examine whether negative symptoms, both in the experiential and expressive dimensions, could mediate the effects of temperament and character on the level of functioning of individuals with PLEs.

METHODS

The study was conducted on 107 healthy young adults with the highest severity of PLEs, selected from a larger sample of 6722 people recruited for another study. Participants were examined using the Cloninger Temperament and Character Inventory, the Brief Negative Symptom Rating Scale, and the Social and Occupational Functioning Assessment Scale.

RESULTS

Both functioning and certain personality traits, such as harm avoidance, persistence, self-directedness, and cooperativeness, were more strongly associated with the occurrence of experiential rather than expressive negative symptoms. We have developed four models, in which we have shown that the experiential negative symptoms mediated the impact of the temperament and character traits on socio-occupational functioning. In each model, negative symptoms weakened the direct effect of the personality trait on functioning.

CONCLUSIONS

These findings suggest that, like at the other stages of psychosis risk, a constellation of specific temperament and character traits is a risk factor for functional decline, which may be partly explained by the effect of experiential negative symptoms. The study also confirms the different impact of the two domains of negative symptoms on functional outcomes, suggesting the need for developing targeted interventions.

The Negative Symptom Inventory-Psychosis Risk (NSI-PR): Psychometric Validation of the Final 11-Item Version

BACKGROUND AND HYPOTHESES

The lack of psychometrically validated assessment tools designed specifically to assess negative symptoms in individuals at clinical high risk (CHR) for psychosis represents a significant barrier to the early identification and prevention of psychosis. To address this need, the Negative Symptom Inventory-Psychosis Risk (NSI-PR) was developed based on the iterative, data-driven approach recommended by the National Institute of Mental Health consensus conference on negative symptoms.

STUDY DESIGN

This manuscript reports the results of the second study phase that psychometrically validates the final 11-item version of the scale in data collected across 3 sites. A total of 222 participants (144 CHR and 78 clinical help-seeking controls) completed the NSI-PR, 1 week of ecological momentary assessment (EMA), and additional convergent and discriminant validity measures.

STUDY RESULTS

Structural analyses replicated the previously reported strong fit for the 5-factor (anhedonia, avolition, asociality, alogia, and blunted affect) and hierarchical structures (2 super-ordinate dimensions and 5 lower-level domains). The 5 domains and 2 dimensions generally demonstrated good internal consistency, temporal stability, and interrater reliability. Convergent validity was demonstrated in relation to the 16-item beta version of the NSI-PR, Structured Interview for Psychosis-risk Syndromes negative subscale, Global Functioning Scale social and role, and EMA measures. Discriminant validity was supported by low correlations with positive, disorganized, and general psychiatric symptoms.

CONCLUSIONS

Findings indicate the final 11-item version of the NSI-PR has sound psychometric properties. The scale, which is designed specifically for CHR individuals, is brief and appropriate for use in research and clinical contexts. Accompanying training materials have been developed to support its use in multisite trials.

Longitudinal Trajectories of Plasma Polyunsaturated Fatty Acids and Associations With Psychosis Spectrum Outcomes in Early Adulthood

BACKGROUND

Evidence supports associations between polyunsaturated fatty acids such as docosahexaenoic acid (DHA) and psychosis. However, polyunsaturated fatty acid trajectories in the general population have not been characterized, and associations with psychosis spectrum outcomes in early adulthood are unknown.

METHODS

Plasma omega-6 to omega-3 ratio and DHA (expressed as percentage of total fatty acids) were measured by nuclear magnetic spectroscopy at 7, 15, 17, and 24 years of age in participants of ALSPAC (Avon Longitudinal Study of Parents and Children). Curvilinear growth mixture modeling evaluated body mass index-adjusted trajectories of both measures. Outcomes were assessed at 24 years. Psychotic experiences (PEs), at-risk mental state status, psychotic disorder, and number of PEs were assessed using the Psychosis-Like Symptoms interview (n = 3635; 2247 [61.8%] female). Negative symptoms score was measured using the Community Assessment of Psychic Experiences (n = 3484; 2161 [62.0%] female). Associations were adjusted for sex, ethnicity, parental social class, and cumulative smoking and alcohol use.

RESULTS

Relative to stable average, the persistently high omega-6 to omega-3 ratio trajectory was associated with increased odds of PEs and psychotic disorder, but attenuated on adjustment for covariates (PEs adjusted odds ratio [aOR] = 1.63, 95% CI = 0.92-2.89; psychotic disorder aOR = 1.69, 95% CI = 0.71-4.07). This was also the case for persistently low DHA (PEs aOR = 1.42, 95% CI = 0.84-2.37; psychotic disorder aOR = 1.14, 95% CI = 0.49-2.67). Following adjustment, persistently high omega-6 to omega-3 ratio was associated with increased number of PEs (β = 0.41, 95% CI = 0.05-0.78) and negative symptoms score (β = 0.43, 95% CI = 0.14-0.72), as was persistently low DHA (number of PEs β = 0.45, 95% CI = 0.14-0.76; negative symptoms β = 0.35, 95% CI = 0.12-0.58).

CONCLUSIONS

Optimization of polyunsaturated fatty acid status during development warrants further investigation in relation to psychotic symptoms in early adulthood.

Interview Versus Performance Assessment of Cognition as Predictors of Real-World Outcomes in a Large-Scale Cross-Sectional Study in Schizophrenia

The Cognitive Assessment Interview (CAI) is an interview-based scale measuring cognitive impairment and its impact on functioning in subjects with schizophrenia (SCZ). It is approved as a coprimary measure of performance-based instruments, such as the Measurement and Treatment Research to Improve Cognition in Schizophrenia Consensus Cognitive Battery (MCCB). Recent research highlights negative symptoms, social cognition, and functional capacity as mediators of cognitive impairment's impact on functioning. This study compared mediation analysis outcomes using CAI or MCCB scores, providing insights into the utility of interview-based tools in research and clinical practice. The study included 618 individuals diagnosed with schizophrenia, recruited from 24 Italian psychiatric clinics. Neurocognitive assessments utilized both CAI and MCCB. Mediation analyses explored negative symptoms, social cognition, and functional capacity as mediators of the impact of neurocognition on real-life functioning domains. The study's results extend the validation of the CAI as a coprimary measure that provides valid information on the impact of cognitive impairment on real-life functioning and its possible mediators, complementing the information obtained using the MCCB. Interview-based cognitive assessment might be essential for understanding schizophrenia complexity and its impact on various cognitive and functional domains for clinicians, patients, and caregivers.

Development and Validation of the Negative Symptom Inventory-Psychosis Risk

BACKGROUND AND HYPOTHESES

Early identification and prevention of psychosis is limited by the availability of tools designed to assess negative symptoms in those at clinical high-risk for psychosis (CHR). To address this critical need, a multi-site study was established to develop and validate a clinical rating scale designed specifically for individuals at CHR: The Negative Symptom Inventory-Psychosis Risk (NSI-PR).

STUDY DESIGN

The measure was developed according to guidelines recommended by the NIMH Consensus Conference on Negative Symptoms using a transparent, iterative, and data-driven process. A 16-item version of the NSI-PR was designed to have an overly inclusive set of items and lengthier interview to support the ultimate intention of creating a new briefer measure. Psychometric properties of the 16-item NSI-PR were evaluated in a sample of 218 CHR participants.

STUDY RESULTS

Item-level analyses indicated that men had higher scores than women. Reliability analyses supported internal consistency, inter-rater agreement, and temporal stability. Associations with measures of negative symptoms and functioning supported convergent validity. Small correlations with positive, disorganized, and general symptoms supported discriminant validity. Structural analyses indicated a 5-factor structure (anhedonia, avolition, asociality, alogia, and blunted affect). Item response theory identified items for removal and indicated that the anchor range could be reduced. Factor loadings, item-level correlations, item-total correlations, and skew further supported removal of certain items.

CONCLUSIONS

These findings support the psychometric properties of the NSI-PR and guided the creation of a new 11-item NSI-PR that will be validated in the next phase of this multi-site scale development project.

Gut microbial signatures and differences in bipolar disorder and schizophrenia of emerging adulthood

INTRODUCTION

Gut microbial disturbance has been established as potential pathogenesis of mental disorders. However, the signatures and differences regarding patients with schizophrenia (SCH) or bipolar disorder (BD) in emerging adulthood as well as their subtypes have been poorly addressed.

METHODS

In the present study, stool samples obtained from 63 emerging adult patients with schizophrenia (SCH), 50 with bipolar disorder (BD), and 40 healthy controls (HC) were analyzed by 16 S rRNA gene sequencing; psychiatric symptoms and psychological, social, and professional functioning were also assessed.

RESULTS

We found that gut microbiota composition was remarkably changed in the patients with SCH and BD. Moreover, the distinct gut microbiome signatures and their potential function in bipolar depression (BP-D) and SCH with predominantly negative symptoms (SCH-N) as well as bipolar mania (BP-M) and SCH with predominantly positive symptoms (SCH-P) were also observed. Furthermore, we identified diagnostic potential biomarkers that can distinguish BD from HC (38 genera, AUC = 0.961), SCH from HC (32 genera, AUC = 0.962), and BD from Scheme (13 genera, AUC = 0.823). Potential diagnostic biomarkers that can distinguish BD-D from SCH-N (16 genera, AUC = 0.969) and BD-M from SCH-P (31 genera, AUC = 0.938) were also identified.

CONCLUSION

This study provides further understanding of abnormal gut microbiome in emerging adulthood patients with SCH and BD and lay the potential foundation for the development of microbe-based clinical diagnosis for BD and SCH.

Longitudinal invariance of psychotic experiences in children and adolescents: What do the data tell us?

BACKGROUND

Psychotic experiences are common in adults, adolescents, and children. While usually self-limited, they can indicate psychosis proneness when persistent. The Community Assessment of Psychic Experiences (CAPE) measures lifetime psychotic experiences in three dimensions. The 20-item subscale addressing positive symptoms (CAPE-positive) is the most widely used. No study investigated its measurement invariance across timepoints during childhood and adolescence. This step is required to conduct reliable comparisons in longitudinal studies with different age groups.

METHODS

We used data from the Brazilian High-Risk Cohort, which enrolled 2511 individuals aged 6-12 years from public schools for the baseline evaluation. A 3-year follow-up assessment evaluated 1880 participants. Subjects were rated with the CAPE-positive and we performed, at each wave, a Multigroup Confirmatory Factor Analysis testing Exploratory and Confirmatory Factor Analysis models identified in a previous systematic review, to assess longitudinal invariance.

RESULTS

A three-factor solution was the best fitting model, comprising Persecutory Ideation, Bizarre Experiences and Perceptual Abnormalities. The longitudinal invariance analysis of the best-fit model was unsatisfactory, achieving only the metric level of invariance.

CONCLUSIONS

Our findings suggest that the CAPE-positive scale has good model fit indices for each evaluated time point individually (children and adolescents), but it is not invariant over time. Identifying which factors affect CAPE latent structure at different time points can improve our understanding of psychosis proneness and how to measure it.