Schizotypy, Lifestyle Behaviors, and Health Indicators in a Young Adult Sample

Reduced MMN-indexed auditory change detection in a non-clinical high schizotypy sample

Schizotypal traits include abnormalities in cognition, behavior, and interpersonal relationships that are similar, yet less severe than psychotic symptomology. It is estimated that approximately 5% of the general population displays psychotic symptoms and experiences that can be considered schizotypal in nature, but there is little research examining the neurological correlates of these traits. The mismatch negativity (MMN) event-related potential is an objective measure of auditory change detection derived from electroencephalography. The current study contributes to the limited body of evidence examining the neurobiological underpinnings of schizotypy in a non-clinical sample using the MMN. Participants were recruited from the general population and divided into high and low-schizotypy groups for comparison. Individuals with high schizotypal traits displayed reduced MMN amplitudes in response to frequency and location deviants, and longer MMN latencies in response to location deviants. Specific sub-traits of schizotypy were uniquely related to frequency and location amplitudes, suggesting the previously reported inconsistencies in the literature may be due to diverse samples and differing deviant tone types. Finally, impulsivity and sensation-seeking likely contributed to the slower processing seen in location deviance detection. Ultimately, the current results provide evidence that the neurobiological abnormalities seen in clinical populations of schizotypal personality disorder and psychosis also extend to non-clinical populations.

Positive and negative schizotypy personality traits are lower in individuals on ketogenic diet in a non-clinical sample

Schizotypal personality comprises traits such as odd beliefs, perceptual abnormalities, and social difficulties; these traits are distributed throughout the general population. While not meeting the clinical threshold for schizophrenia or schizotypal personality disorder, schizotypal personality traits still provide insights for understanding early clinical risk factors. Ketogenic diet reportedly reduces psychotic symptoms in preclinical and clinical studies. Therefore, we investigated whether ketogenic diet is associated with lower schizotypal traits in the general population. Participants following a ketogenic or other diet were recruited using opportunity sampling. Individuals completed a survey investigating general demographic, socioeconomic, health, diet and lifestyle questions, followed by the Schizotypal Personality Questionnaire - Brief Revised version (SPQ-BR). We found that individuals following a ketogenic diet (n = 118) had lower ideas of reference, magical thinking, suspiciousness, unusual perceptions, constricted affect, social anxiety scores, cognitive (positive) perceptual scores, interpersonal (negative) scores and total SPQ-BR compared to individuals on the other diets (n = 139). Magical thinking, constricted affect, social anxiety, cognitive perceptual, interpersonal scores and total SPQ-BR scores remained significant when we controlled for body mass index (BMI) and age. Disorganised features were not influenced by ketogenic diet. The longer individuals adhered to a ketogenic diet the lower their positive and negative schizotypy traits. These findings highlight that ketogenic diet is associated with lower non-clinical schizotypal personality traits. Our results suggest that ketogenic diet might have potential prophylactic properties for individuals at-risk for psychosis.

Schizotypal traits in a large sample of high-school and university students from Tunisia: correlates and measurement invariance of the arabic schizotypal personality questionnaire across age and sex

BACKGROUND

The main goal of the present study was to examine the characteristics of schizotypal traits and their correlations with genetic (i.e., family history of mental illness), demographic (i.e., age, sex), environmental (e.g., income, urbanicity, tobacco/alcohol/cannabis use), and psychological (i.e., personal history of mental illness other than psychosis) factors in Tunisian high-school and university students. Our secondary goal was to contribute the literature by examining the factor structure and factorial invariance of the Arabic Schizotypal Personality Questionnaire (SPQ) across sex and age (adolescents [12-18 years] vs. young adults [18-35 years]) groups.

METHOD

This was a cross-sectional study involving 3166 students: 1160 (36.6%) high-school students (53.0% females, aged 14.9 ± 1.8); and 2006 (63.4%) university students (63.9% females, aged 21.8 ± 2.3). All students were asked to complete a paper-and-pencil self-administered questionnaire containing sociodemographic characteristics as well as the Arabic version of the SPQ.

RESULTS

The total sample yielded total SPQ scores of 24.1 ± 16.6 out of 74. The SPQ yielded good composite reliability as attested by McDonald's omega values ranging from .68 to .80 for all nine subscales. Confirmatory Factor Analysis indicated that fit of the 9-factor model of SPQ scores was acceptable. This model is invariant (at the configural, metric and structural levels) across sex and age. Except for "Odd or eccentric behavior", all schizotypy features were significantly higher among female students compared to males. Multivariable analyses showed that female sex, being a university student, lowest family incomes, tobacco use, and having a personal history of psychiatric illness were significantly associated with higher positive, negative and disorganized schizotypy subscales scores.

CONCLUSION

Future research still needs to confirm our findings and investigate the contribution of the identified factors in the development of clinical psychosis. We can also conclude that the Arabic SPQ is appropriate for measuring and comparing schizotypy across age and sex in clinical and research settings. These findings are highly relevant and essential for ensuring the clinical utility and applicability of the SPQ in cross-cultural research.

Examining the impact of schizotypal personality traits on event-related potential (ERP) indexes of sensory gating in a healthy population

The aim of this study was to better understand the relation of schizotypy traits with sensory gating ability in a sample of community-dwelling individuals with high and low schizotypy traits. Sensory gating was assessed through the paired click paradigm and mid-latency evoked responses (i.e., P50, N100, P200), while schizotypy traits were assessed through the SPQ-BR which was used to classify participants into "high" and "low" schizotypy groups. Based on prior work, we hypothesized that those with the highest schizotypy scores would have reduced sensory gating ability. While this study does not show differences between relatively low and high schizotypy groups on sensory gating ability, it does suggest that our participants may have been experiencing deficits in attention allocation, a downstream cognitive processing measure. Scores on the SPQ-BR suggest that our sample was not close to the high end of the schizotypy traits which may help explain why no differences were found. This research shows the importance of including all levels of schizotypy ratings in clinical research as we can gain a clearer view of the impact of schizotypy on the brain and cognitive functioning in those with "high" levels of schizotypy. Additionally, this work highlights the importance of including measures of important factors such as impulsivity and sensation-seeking to better understand what aspects of schizotypy may be driving these sensory gating alterations reported in the literature.

Nutrition, Sleep, and Exercise as Healthy Behaviors in Schizotypy: A Scoping Review

This scoping review identifies the role of nutrition, sleep, and exercise as healthy behaviors in non-clinical individuals with schizotypy throughout the lifespan.

METHODS

We systematically reviewed the existing literature on these topics through databases including: PsycINFO, Scopus, APA PsycNet, ScienceDirect, Wiley Online Library, and SpringerLink.

RESULTS

Of the 59 studies found, a total of 29 studies met the inclusion criteria on the review topic. Included studies reflect varying study designs (cross-sectional, multiple time-point, intervention, randomized-placebo controlled trials), assessment of schizotypy and associated healthy behaviors, focus on various samples and lifespan (e.g., undergraduates, adolescents, at-risk individuals), and stem from different countries.

CONCLUSION

While a moderate number of studies address the role of nutrition, sleep, and physical exercise in relation to schizotypy, studies intersecting these topics are limited. Of the limited studies that do exist, the majority are correlational with the beginnings of causal support from intervention studies. As such, more research is needed on the topics of nutrition, sleep, and exercise in relation to schizotypy. Specifically, future research should focus on providing a more holistic understanding of schizotypal traits and its subtypes, and which specific or combination of behaviors may reduce levels of schizotypy.

Domains of Vulnerability, Resilience, Health Habits, and Mental and Physical Health for Health Disparities Research

Health disparities associated with severe mental illness (SMI) have become a major public health concern. The disparities are not directly due to the SMI. They involve the same leading causes of premature death as in the general population. The causes of the disparities are therefore suspected to reflect differences in health-related behavior and resilience. As with other problems associated with SMI, studying non-clinical populations at risk for future onset provides important clues about pathways, from vulnerability to unhealthy behavior and compromised resilience, to poor health and reduced quality of life. The purpose of this study was to identify possible pathways in a sample of public university students. Four domains of biosystemic functioning with a priori relevance to SMI-related vulnerability and health disparities were identified. Measures reflecting various well-studied constructs within each domain were factor-analyzed to identify common sources of variance within the domains. Relationships between factors in adjacent domains were identified with linear multiple regression. The results reveal strong relationships between common factors across domains that are consistent with pathways from vulnerability to health disparities, to reduced quality of life. Although the results do not provide dispositive evidence of causal pathways, they serve as a guide for further, larger-scale, longitudinal studies to identify causal processes and the pathways they follow to health consequences.