A latent profile analysis of schizotypy, temperament and character in a nonclinical population: association with neurocognition

Association between personality profiles and symptomatology patterns based on TCI and MMPI-2-RF in a transdiagnostic psychiatric sample: A person-centered approach

BACKGROUND

The temperament and character dimensions of personality appear to be networking structures that interact nonlinearly. Previous studies have attempted to classify temperament and character subtypes using a person-centered approach but have been unable to explore the relationship between the combination of temperament and character and psychopathology patterns in a transdiagnostic sample. The purpose of this study was to examine how symptomatology patterns differ according to individuals' personality profiles, employing a psychobiological model in a transdiagnostic psychiatric sample.

METHODS

Participants were 1881 patients who visited the psychiatry department of a major medical hospital in Seoul, Korea, and completed both the Temperament Character Inventory (TCI) and the Minnesota Multiphasic Personality Inventory-2-Restructed Form (MMPI-2-RF) as part of their psychological evaluation. We performed two separate latent profile analyses using four temperament and four character indicators of the TCI to identify personality profiles and nine restructured clinical scales of the MMPI-2-RF to identify symptom patterns.

RESULTS

Five personality classes emerged: "vulnerable-maladaptive," "stable-adaptive," "average," "inhibited-neurotic," and "impulsive-irrational." Moreover, six symptom classes emerged: "non-distressed," "depressed," "emotionally-distressed," "average," "dysfunctional thoughts," and "confused." The personality profiles comprising a combination of rigid temperament and immature character were related to patterns of more severe subjective pain and symptoms. However, profiles with less rigid temperament and less immature character exhibited more diverse symptom patterns.

CONCLUSIONS

This study examined the relationship between personality profiles and symptomatology patterns, suggesting that understanding patients' personality profiles may be helpful in predicting symptom manifestation and establishing treatment plans.

Variations in Well-Being as a Function of Paranormal Belief and Psychopathological Symptoms: A Latent Profile Analysis

This study examined variations in well-being as a function of the interaction between paranormal belief and psychopathology-related constructs. A United Kingdom-based, general sample of 4,402 respondents completed self-report measures assessing paranormal belief, psychopathology (schizotypy, depression, manic experience, and depressive experience), and well-being (perceived stress, somatic complaints, and life satisfaction). Latent profile analysis identified four distinct sub-groups: Profile 1, high Paranormal Belief and Psychopathology (n = 688); Profile 2, high Paranormal Belief and Unusual Experiences; moderate Psychopathology (n = 800); Profile 3, moderate Paranormal Belief and Psychopathology (n = 846); and Profile 4, low Paranormal Belief and Psychopathology (n = 2070). Multivariate analysis of variance (MANOVA) found that sub-groups with higher psychopathology scores (Profiles 1 and 3) reported lower well-being. Higher Paranormal Belief, however, was not necessarily associated with lower psychological adjustment and reduced well-being (Profile 2). These outcomes indicated that belief in the paranormal is not necessarily non-adaptive, and that further research is required to identify the conditions under which belief in the paranormal is maladaptive.

Adaptive and maladaptive features of schizotypy clusters in a community sample

Schizotypal personality traits correlate with psychopathology and impaired functional outcome. Yet advantageous aspects of positive schizotypy may exist which could promote resilience and creativity, and several studies have identified a high positive but low negative schizotypy group with some signs of adaptation. The aim of our study was to clarify whether such individuals demonstrate only traits associated with well-being, or they also have traits that predict impairment. Participants (N = 643 students, 71.5% female) completed measures of schizotypy, resilience, self-esteem, self-concept clarity, and absorption. We identified four clusters: an overall low schizotypy, an overall high schizotypy, a disorganised-interpersonal schizotypy and a positive schizotypy cluster. The overall high schizotypy cluster seemed to be the most vulnerable as it was the least resilient and showed widespread maladaptation, whereas the high positive schizotypy cluster had intact self-esteem and high resilience and its elevated absorption may hold the promise for adaptive outcomes such as creativity and positive spirituality. However, the high positive schizotypy cluster lacked self-concept clarity. The results suggest that individuals showing high positive and low negative schizotypy demonstrate features promoting mental well-being to an extent that is higher than in all the other clusters, while their self-concept impairment is similar to that observed in the high and the disorganised-interpersonal schizotypy clusters. Better understanding of these factors could be informative for prevention and treatment of psychosis-spectrum disorders.

Schizotypal traits and neuropsychological performance: The role of processing speed

BACKGROUND

Cognitive deficits, particularly in processing speed, are widely recognized as a critical feature of schizophrenia, and are also present across schizophrenia spectrum disorders. A number of important confounders, however, such as hospitalization effects and antipsychotic medication, have been shown to affect processing speed, causing debate as to the core cognitive deficits of schizophrenia. The study of individuals who are not clinically psychotic but have schizotypal traits allows investigation of cognitive deficits associated with both positive and negative schizotypy dimensions while excluding potential confounds.

METHODS

A population-based community sample of 242 healthy adult volunteers assessed using the Structured Interview of Schizotypy - Revised (SIS-R) scale, and a neuropsychological testing battery that included measures of verbal ability, visual and verbal memory, verbal fluency, working memory, executive functions and processing speed. Participants were classified in High or Low Positive Schizotypy (H-PST or L-PST), High or Low Paranoia-like traits (H-PAR or L-PAR) and High or Low Negative Schizotypy (H-NST or L-NST) groups, respectively.

RESULTS

Individuals with H-PST performed significantly (p < 0.05) worse than L-PST on measures of processing speed and executive functions. Processing speed deficits were also observed in individuals with H-PAR compared to L-PAR (p < 0.05). There were no statistically significant differences in neuropsychological performance between H-NST and L-NST on any measure.

CONCLUSIONS

In a population-based community sample, individuals with high positive schizotypal traits or paranoia-like traits show impairments in processing speed. Consistent with a dimensional view of psychosis, this supports the hypothesis that processing speed represents a core deficit of schizophrenia-like mental states.

Identifying extended psychosis phenotypes at school: Associations with socio-emotional adjustment, academic, and neurocognitive outcomes

The main goal of the present study was to explore the latent structure of extended psychosis phenotypes in a representative sample of adolescents. Moreover, associations with socio-emotional adjustment, academic achievement, and neurocognition performance across the latent profiles were compared. Participants were 1506 students, 667 males (44.3%), derived from random cluster sampling. Various tools were used to measure psychosis risk, subjective well-being, academic performance, and neurocognition. Based on three psychometric indicators of psychosis risk (schizotypal traits, psychotic-like experiences, and bipolar-like experiences), four latent classes were found: non-risk, low-risk, high reality distortion experiences, and high psychosis liability. The high-risk latent groups scored significantly higher on mental health difficulties, and negative affect, and lower on positive affect and well-being, compared to the two non-risk groups. Moreover, these high-risk groups had a significantly higher number of failed academic subjects compared to the non-risk groups. In addition, no statistically significant differences in efficiency performance were found in the neurocognitive domains across the four latent profiles. This study allows us to improve the early identification of adolescents at risk of serious mental disorder in school settings in order to prevent the incidence and burden associated with these kinds of mental health problems.

Defining Subtypes in Children with Nail Biting: A Latent Profile Analysis of Personality

OBJECTIVE

This study aimed to examine personality profiles and behavioral problems of children with nail biting (NB) to gain insight into the developmental trajectory of pathological NB.

METHODS

681 elementary school students were divided into non NB (n=436), occasional NB (n=173) and frequent NB group (n=72) depending on the frequency of NB reported in Child Behavioral Checklist (CBCL). Children's personality was assessed using the Junior Temperament and Character Inventory (JTCI), and behavioral problems were assessed using the CBCL. Latent Profile Analysis (LPA) was performed using JTCI profiles to classify personalities of the children with NB (belonging to frequent and occasional NB group, n=245).

RESULTS

For subscale scores of CBCL, the total, internalizing, externalizing, anxious/depressed withdrawn/depressed, depression, thought, rule-breaking, and aggressive behavior problems, were most severe in the frequent NB group followed by occasional NB and non NB group. LPA of personality profile in children with NB revealed four classes ('adaptiveness,' 'high reward dependence,' 'low self-directedness,' and 'maldaptiveness'). The four personality classes demonstrated significant group differences in all of the CBCL subscales. Children who showed low self-directedness and cooperativeness and high novelty seeking and harm avoidance personality profiles demonstrated highest tendency for problematic behavior irrespective of the frequency of NB.

CONCLUSION

Children with NB reported significantly more problematic behaviors compared to children without NB. Children with specific personality profile demonstrated higher tendency for problematic behavior irrespective of the frequency of NB. Therefore, accompanying personality profiles should be considered when assessing behavioral problems in children with NB.

Latent profile analysis of psychosis liability in a community-derived sample of adolescents: Links with mental health difficulties, suicidal ideation, bipolar-like experiences and psychotic-like experiences

AIM

The main goal of the present study was to explore the latent structure of schizotypy as an indicator of psychosis liability, in a community-derived sample of adolescents. Links to mental health difficulties, prosocial behaviour, suicidal ideation, bipolar-like experiences and psychotic-like experiences (PLEs) (severity and distress) were compared across schizotypy latent profiles.

METHOD

The present research included 1588 adolescents selected by a stratified random cluster sampling. The Oviedo Schizotypy Assessment Questionnaire (ESQUIZO-Q), The Paykel Suicide Scale (PSS), The Strengths and Difficulties Questionnaire (SDQ), The Prodromal Questionnaire-Brief (PQ-B), The Mood Disorder Questionnaire (MDQ), The Penn Matrix Reasoning Test (PMRT), The Family Affluence Scale-II (FAS-II), and The Oviedo Infrequency Scale (INF-OV) were used.

RESULTS

Using latent profile analysis four latent classes (LC) were identified: "Positive schizotypy" (14.1%, n = 224), "Low schizotypy" (51.9%, n = 825), "Social Disorganization schizotypy" (27.2%, n = 432), and "High schizotypy" (6.7%, n = 107). The "High schizotypy" class scored higher on several psychometric indicators of psychopathology (ie, mental health difficulties, suicide ideation, bipolar-like experiences and PLEs) relative to the other three LC.

CONCLUSION

Four groups of adolescents with different patterns of schizotypal traits and different clinical-pathological meaning were found. Deficits found across schizotypy latent profiles, resembling those found in patients with psychosis and ultra-high risk samples. The identification of homogeneous subgroups of adolescents potentially at risk for psychosis may help us in the prevention of psychotic-spectrum disorders and mental health problems.

Differential emotional abnormalities among schizotypy clusters

Schizotypy, a multidimensional personality organization that reflects liability to develop schizophrenia-spectrum disorders, has been associated with a number of emotional abnormalities. Yet, the exact nature of any emotional abnormalities in schizotypy is relatively unclear. Using an ethnically diverse nonclinical sample (N = 2637), the present study identified homogenous clusters of individuals based on positive and negative schizotypy dimensions and explored three interrelated domains of emotion traits closely tied to functional outcomes and quality of life: affective experience, emotional awareness, and meta-level emotions. Consistent with prior research, four schizotypy clusters were obtained: low ("nonschizotypic"), high positive, high negative, and mixed (high positive and high negative). Regarding emotion correlates of schizotypy clusters, the mixed cluster was found to be the most deviant on almost all emotion traits (e.g., heightened trait negative affect, diminished emotional clarity), suggesting that the effects of positive and negative schizotypy are additive. In addition, positive and negative schizotypy clusters were associated with differential abnormalities, with the negative cluster presenting a wider range of, and more severe, impairments compared to the low cluster (e.g., reduced trait positive affect and reduced attention to positive emotion). The current study highlights the heterogeneity in emotional traits among schizotypy dimensions and the importance of studying the mixed schizotypy in terms of emotional dysfunction.

Integrated profiling of phenotype and blood transcriptome for stress vulnerability and depression

Etiology of depression and its vulnerability remains elusive. Using a latent profile analysis on dimensional personality traits, we previously identified 3 different phenotypes in the general population, namely stress-resilient, -vulnerable, and -resistant groups. Here we performed microarray-based blood gene expression profiling of these 3 groups (n = 20 for each group) in order to identify genes involved in stress vulnerability as it relates to the risk of depression. Identified differentially expressed genes among the groups were most markedly enriched in ribosome-related pathways. These ribosomal genes, which included ribosomal protein L17 (RPL17) and ribosomal protein L34 (RPL34), were upregulated in relation to the stress vulnerability. Protein-protein interaction and correlational co-expression analyses of the differentially expressed genes/non-coding RNAs consistently showed that functional networks involving ribosomes were affected. The significant upregulation of RPL17 and RPL34 was also observed in depressed patients compared to healthy controls, as confirmed in 2 independent case-control datasets by using pooled microarray data and qPCR experiments (total number of subjects was 122 and 166, respectively). Moreover, the upregulation of RPL17 and RPL34 was most marked in DSM-IV major depressive disorder, followed by in bipolar disorder, and then in schizophrenia, suggesting some diagnostic specificity of these markers as well as their general roles in stress vulnerability. These results suggest that ribosomal genes, particularly RPL17 and RPL34, can play integral roles in stress vulnerability and depression across nonclinical and clinical conditions. This study presents an opportunity to understand how multiple psychological traits and underlying molecular mechanisms interact to render individuals vulnerable to depression.

Individual differences in first- and second-order temporal judgment

The ability of subjects to identify and reproduce brief temporal intervals is influenced by many factors whether they be stimulus-based, task-based or subject-based. The current study examines the role individual differences play in subsecond and suprasecond timing judgments, using the schizoptypy personality scale as a test-case approach for quantifying a broad range of individual differences. In two experiments, 129 (Experiment 1) and 141 (Experiment 2) subjects completed the O-LIFE personality questionnaire prior to performing a modified temporal-bisection task. In the bisection task, subjects responded to two identical instantiations of a luminance grating presented in a 4deg window, 4deg above fixation for 1.5 s (Experiment 1) or 3 s (Experiment 2). Subjects initiated presentation with a button-press, and released the button when they considered the stimulus to be half-way through (750/1500 ms). Subjects were then asked to indicate their 'most accurate estimate' of the two intervals. In this way we measure both performance on the task (a first-order measure) and the subjects' knowledge of their performance (a second-order measure). In Experiment 1 the effect of grating-drift and feedback on performance was also examined. Experiment 2 focused on the static/no-feedback condition. For the group data, Experiment 1 showed a significant effect of presentation order in the baseline condition (no feedback), which disappeared when feedback was provided. Moving the stimulus had no effect on perceived duration. Experiment 2 showed no effect of stimulus presentation order. This elimination of the subsecond order-effect was at the expense of accuracy, as the mid-point of the suprasecond interval was generally underestimated. Response precision increased as a proportion of total duration, reducing the variance below that predicted by Weber's law. This result is consistent with a breakdown of the scalar properties of time perception in the early suprasecond range. All subjects showed good insight into their own performance, though that insight did not necessarily correlate with the veridical bisection point. In terms of personality, we found evidence of significant differences in performance along the Unusual Experiences subscale, of most theoretical interest here, in the subsecond condition only. There was also significant correlation with Impulsive Nonconformity and Cognitive Disorganisation in the sub- and suprasecond conditions, respectively. Overall, these data support a partial dissociation of timing mechanisms at very short and slightly longer intervals. Further, these results suggest that perception is not the only critical mitigator of confidence in temporal experience, since individuals can effectively compensate for differences in perception at the level of metacognition in early suprasecond time. Though there are individual differences in performance, these are perhaps less than expected from previous reports and indicate an effective timing mechanism dealing with brief durations independent of the influence of significant personality trait differences.

Latent Profile Analysis of Schizotypy and Paranormal Belief: Associations with Probabilistic Reasoning Performance

This study assessed the extent to which within-individual variation in schizotypy and paranormal belief influenced performance on probabilistic reasoning tasks. A convenience sample of 725 non-clinical adults completed measures assessing schizotypy (Oxford-Liverpool Inventory of Feelings and Experiences; O-Life brief), belief in the paranormal (Revised Paranormal Belief Scale; RPBS) and probabilistic reasoning (perception of randomness, conjunction fallacy, paranormal perception of randomness, and paranormal conjunction fallacy). Latent profile analysis (LPA) identified four distinct groups: class 1, low schizotypy and low paranormal belief (43.9% of sample); class 2, moderate schizotypy and moderate paranormal belief (18.2%); class 3, moderate schizotypy (high cognitive disorganization) and low paranormal belief (29%); and class 4, moderate schizotypy and high paranormal belief (8.9%). Identification of homogeneous classes provided a nuanced understanding of the relative contribution of schizotypy and paranormal belief to differences in probabilistic reasoning performance. Multivariate analysis of covariance revealed that groups with lower levels of paranormal belief (classes 1 and 3) performed significantly better on perception of randomness, but not conjunction problems. Schizotypy had only a negligible effect on performance. Further analysis indicated that framing perception of randomness and conjunction problems in a paranormal context facilitated performance for all groups but class 4.

A personality-based latent class typology of outpatients with major depressive disorder: association with symptomatology, prescription pattern and social function

BACKGROUND

While major depressive disorder (MDD) is considered to be a heterogeneous disorder, the nature of the heterogeneity remains unclear. Studies have attempted to classify patients with MDD using latent variable techniques, yet the empirical approaches to symptom-based subtyping of MDD have not provided conclusive evidence. Here we aimed to identify homogeneous classes of MDD based on personality traits, using a latent profile analysis.

METHODS

We studied 238 outpatients with DSM-IV MDD recruited from our specialized depression outpatient clinic and assessed their dimensional personality traits with the Temperament and Character Inventory. Latent profile analysis was conducted with 7 dimensions of the Temperament and Character Inventory as indicators. Relationships of the identified classes with symptomatology, prescription pattern, and social function were then examined.

RESULTS

The latent profile analysis indicated that a 3-class solution best fit the data. Of the sample, 46.2% was classified into a "neurotic" group characterized by high harm avoidance and low self-directedness; 30.3% into an "adaptive" group characterized by high self-directedness and cooperativeness; and 23.5% into a "socially-detached" group characterized by low reward dependence and cooperativeness and high self-transcendence. The 2 maladaptive groups, namely neurotic and socially-detached groups, demonstrated unique patterns of symptom expression, different classes of psychotropic medication use, and lower social functioning.

LIMITATIONS

Generalizability of the findings was limited since our patients were recruited from the specialized depression outpatient clinic.

CONCLUSIONS

Our personality-based latent profile analysis identified clinically meaningful 3 MDD groups that were markedly different in their personality profiles associated with distinct symptomatology and functioning.

A latent profile analysis of schizotypal dimensions: Associations with psychopathology and personality

The main goal of the present study was to explore the latent structure of schizotypal traits in non-clinical young adults, and compare the latent profiles in clinical and personality characteristics: mental distress, psychosis-proneness, hypomanic experiences, and anticipatory and consummatory pleasure. A large sample of college students (N =1002; mean age =21.11 years; SD =3.92) were administered the Schizotypal Personality Questionnaire-Brief Revised, the Mood Disorder Questionnaire, the short version of the Oxford-Liverpool Inventory of Feelings and Experiences, the General Health Questionnaire-12, and the Temporal Experience of Pleasure Scale. Using latent profile analysis, four latent classes (LC) were identified: "low schizotypy" (62.4%), "average schizotypy" (17.6%), "interpersonal schizotypy" (17.1%), and "high schizotypy" (2.9%). The "high schizotypy" class scored higher on most psychometric indicators of psychopathology and personality (i.e., mental distress, schizotypy, hypomanic experiences, and anticipatory and consummatory pleasure) relative to other three latent classes. The other three schizotypal latent profiles also varied in terms of these psychopathology and personality factors. The identification of homogeneous subgroups of individuals potentially at-risk for psychosis based on schizotypal latent profiles may improve early identification and prevention efforts aimed at reducing the burden associated with psychotic-spectrum disorders and mental health problems.

Neuropsychological correlates of schizotypy: a systematic review and meta-analysis of cross-sectional studies

INTRODUCTION

Cognitive deficits can precede the onset of psychotic episodes and predict the onset of the illness in individuals with schizotypy traits. In some studies, high levels of schizotypy were associated with impairments in memory, attention, executive functions, and verbal fluency. This review provides a more comprehensive understanding of cognitive impairments related to schizoytpy.

METHODS

 A systematic review of "schizotypy and neuropsychological measures" was conducted, and it retrieved 67 studies. All papers with case-control design showing means and standard deviations from neuropsychological measures were included in a meta-analysis (n = 40). A comparison between our finding and another metaanalysis with patients with schizophrenia-spectrum disorders [Fatouros-Bergman, H., Cervenka, S., Flyckt, L., Edman, G., & Farde, L. (2014). Meta-analysis of cognitive performance in drugnaive patients with schizophrenia. Schizophrenia Research. doi: 10.1016/j.schres.2014.06.034 ] was performed to study the similarities on the MATRICS domains between the two disorders.

RESULTS

We found evidence of worse functioning of verbal and visual-spatial working memory, and of language in people with schizotypy or with schizotypal traits. Working memory deficit is present in both schizotypy and schizophrenia with larger effect sizes compared to other domains.

CONCLUSIONS

 Working memory deficit might be a cognitive marker of the risk of psychosis. Interventions targeting cognitive deficits early may be crucial to the prevention of psychosis.

How to tell a happy from an unhappy schizotype: personality factors and mental health outcomes in individuals with psychotic experiences

Objective:

It is unclear why some individuals reporting psychotic experiences have balanced lives while others go on to develop mental health problems. The objective of this study was to test if the personality traits of harm avoidance, self-directedness, and self-transcendence can be used as criteria to differentiate healthy from unhealthy schizotypal individuals.

Methods:

We interviewed 115 participants who reported a high frequency of psychotic experiences. The instruments used were the Temperament and Character Inventory (140), Structured Clinical Interview for DSM-IV, and the Oxford-Liverpool Inventory of Feelings and Experiences.

Results:

Harm avoidance predicted cognitive disorganization (β = 0.319; t = 2.94), while novelty seeking predicted bipolar disorder (β = 0.136, Exp [β]. = 1.146) and impulsive non-conformity (β = 0.322; t = 3.55). Self-directedness predicted an overall decrease in schizotypy, most of all in cognitive disorganization (β = -0.356; t = -2.95) and in impulsive non-conformity (β = -0.313; t = -2.83). Finally, self-transcendence predicted unusual experiences (β = 0.256; t = 2.32).

Conclusion:

Personality features are important criteria to distinguish between pathology and mental health in individuals presenting high levels of anomalous experiences (AEs). While self-directedness is a protective factor, both harm avoidance and novelty seeking were predictors of negative mental health outcomes. We suggest that the impact of AEs on mental health is moderated by personality factors.

White matter correlates of psychosis-linked traits support continuity between personality and psychopathology

The link between diagnoses of psychotic disorders and attenuated white matter connectivity is well established, but little is known about the degree to which similar white matter differences predict traits linked to psychosis-proneness in the general population. Moreover, intelligence is too rarely considered as a covariate in neural endophenotype studies, despite its known protective role against psychopathology in general and its associations with broad aspects of neural structure and function. To determine whether psychosis-linked personality traits are linearly associated with white matter microstructure, we examined white matter correlates of Psychoticism, Absorption, and Openness to Experience in a large community sample, covarying for sex, age, and IQ. Findings support our hypothesis that the white matter correlates of the shared variance of these traits overlap substantially with the frontal lobe white matter connectivity patterns characteristic of psychotic spectrum disorders. These findings provide biological support for the notion that liability to psychosis is distributed throughout the population, is evident in brain structure, and manifests as normal personality variation at subclinical levels. (PsycINFO Database Record

Classifying risk status of non-clinical adolescents using psychometric indicators for psychosis spectrum disorders

This study is an attempt to evaluate extant psychometric indicators using latent profile analysis for classifying community-derived individuals based on a set of clinical, behavioural, and personality traits considered risk markers for psychosis spectrum disorders. The present investigation included four hundred and forty-nine high-school students between the ages of 12 and 19. We used the following to assess risk: the Prodromal Questionnaire-Brief (PQ-B), Oviedo Schizotypy Assessment Questionnaire (ESQUIZO-Q), Anticipatory and Consummatory Interpersonal Pleasure Scale-Adolescent version (ACIPS-A), and General Health Questionnaire 12 (GHQ-12). Using Latent profile analysis six latent classes (LC) were identified: participants in class 1 (LC1) displayed little or no symptoms and accounted for 38.53% of the sample; class 2 (LC2), who accounted for 28.06%, also produced low mean scores across most measures though they expressed somewhat higher levels of subjective distress; LC3, a positive schizotypy group (10.24%); LC4 (13.36%), a psychosis high-risk group; LC5, a high positive and negative schizotypy group (4.45%); and LC6, a very high distress, severe clinical high-risk group, comprised 5.34% of the sample. The current research indicates that different latent classes of early individuals at risk can be empirically defined in adolescent community samples using psychometric indicators for psychosis spectrum disorders. These findings may have implications for early detection and prevention strategies in psychosis spectrum disorders.

Cognitive biases mediate the relationship between temperament and character and psychotic-like experiences in healthy adults

Psychotic-like experiences (PLEs) are frequently reported in the general population. Healthy individuals reporting PLEs have a similar personality profile to people with psychosis; however, the mechanisms by which personality influences PLEs are unclear. This study tests the hypothesis that cognitive biases mediate the relationship between two dimensions of personality (i.e. temperament and character) and positive and negative PLEs. Two hundred and ninety-six healthy participants were assessed using the Community Assessment of Psychic Experiences scale, the Temperament and Character Inventory and the Davos Scale for Cognitive Biases. We performed multiple stepwise regression analysis and mediation analysis according to Baron and Kenny׳s method. Harm-avoidance and self-directedness personality dimensions significantly predicted PLEs frequency. High self-transcendence and lower cooperativeness predicted positive PLEs. Cognitive biases were significant mediators in relationships between temperament, character and both positive and negative PLEs. In particular, attention to threat and external attribution biases fully mediate the relationship between cooperativeness and positive PLEs. Other cognitive biases partially mediate the relationships between self-transcendence and positive PLEs and self-directedness, harm-avoidance and negative PLEs. Our study tentatively suggests that personality may influence PLEs via the cognitive bias pathway.

Cognitive effects of the ANK3 risk variants in patients with bipolar disorder and healthy individuals

BACKGROUND

Genetic variants within the ankyrin 3 gene (ANK3) have been identified as a risk factor for bipolar disorder. ANK3 influences action potential generation by clustering sodium gated channels and plays an integral role in neurotransmission. Thus, this gene may influence cognition, a process compromised in bipolar disorder. We investigated whether genetic variants of ANK3 would be associated with an array of cognitive functions in patients with bipolar disorder and healthy individuals.

METHODS

In a sample of 49 patients with bipolar disorder and 633 healthy subjects, we examined possible effects of 2 risk variants within ANK3, rs10994336 and rs10761482, on 7 neurocognitive domains.

RESULTS

Compared to healthy subjects, patients with bipolar disorder demonstrated significantly poorer performance on most of the cognitive domains examined. The risk C-allele of rs10761482 was significantly associated with worse performance on verbal comprehension, logical memory and processing speed in patients. This allele was significantly associated with worse performance on executive function and visual memory in healthy individuals. No significant association was observed between rs10994336 and cognition either in patients or healthy individuals.

LIMITATIONS

The sample size of patients with bipolar disorder was small, and most of the patients were on psychotropic medication.

CONCLUSIONS

These results indicate that a risk variant within ANK3 may have an impact on neurocognitive function, suggesting a mechanism by which ANK3 confers risk for bipolar disorder.

Genetic and environmental bases of the interplay between magical ideation and personality

Sub-threshold psychotic symptoms are quite commonly present in general population. Among these, Magical Ideation (MI) has been proved to be a valid predictor of psychosis. However, the genetic and environmental influences on the interplay between MI and personality have not fully been explored. A total of 534 adult twins from the population-based Italian Twin Register were assessed for MI using the MI Scale (MIS) and for personality with the temperament and character inventory (TCI). A Multivariate Cholesky model was applied with Mx statistical program. The best-fitting model showed that additive genetic and unshared environmental factors explain approximately the same proportion of variance in MI, whereas a less strong genetic influence on personality traits emerged. Relevant correlations between MI and specific personality traits (novelty seeking, cooperativeness, self-directedness, self-transcendence) were found, suggesting shared influences for MI and these traits. Both genetic and environmental factors explained these correlations, with genetic factors playing a predominant role. Moderate-to-substantial genetic effects on MI and personality were found. Shared genetic and environmental effects underlie the phenotypic correlation between MI (psychosis-proneness) and personality traits, i.e. self-directedness (negative association) and self-transcendence (positive association), potentially representing predictive markers of psychosis liability related to schizotypy and personality.