The relationship between temperament and character and subclinical psychotic-like experiences in healthy adults

Aberrant Salience among Young Healthy Postgraduate University Students: The Role of Cannabis Use, Psychotic-Like Experiences, and Personality

Aberrant salience (AS) is an anomalous world experience which plays a major role in psychotic proneness. In the general population, a deployment of this construct - encompassing personality traits, psychotic-like symptoms, and cannabis use - could prove useful to outline the relative importance of these factors. For this purpose, 106 postgraduate university students filled the AS Inventory (ASI), the Community Assessment of Psychic Experiences (CAPE), the Temperament and Character Inventory (TCI), and the Symptom Checklist 90-Revised (SCL-90-R). Lifetime cannabis users (n = 56) and individuals who did not use cannabis (n = 50) were compared. The role of cannabis use and psychometric indexes on ASI total scores was tested in different subgroups (overall sample, cannabis users, and nonusers). The present study confirmed that cannabis users presented higher ASI scores. The deployment of AS proved to involve positive symptom frequency (assessed through CAPE), character dimensions of self-directedness and self-transcendence (TCI subscales), and cannabis use. Among nonusers, the role of personality traits (assessed through the TCI) was preeminent, whereas positive psychotic-like experiences (measured by means of CAPE) had a major weight among cannabis users. The present study suggests that pre-reflexive anomalous world experiences such as AS are intertwined with reflexive self-consciousness, personality traits, current subclinical psychotic symptoms, and cannabis use. In the present study, subthreshold psychotic experiences proved to play a major role among cannabis users, whereas personality appeared to be more relevant among nonusers.

Magical thinking in individuals with high polygenic risk for schizophrenia but no non-affective psychoses-a general population study

A strong genetic background for psychoses is well-established. Most individuals with a high genetic risk for schizophrenia, however, do not develop the disorder. We investigated whether individuals, who have a high genetic risk for schizophrenia but no non-affective psychotic disorders, are predisposed to develop milder forms of deviant thinking in terms of magical thinking. Participants came from the population-based Young Finns Study (n = 1292). The polygenic risk score for schizophrenia (PRS) was calculated on the basis of the most recent genome-wide association study (GWAS). Psychiatric diagnoses over the lifespan were collected up to 2017 from the registry of hospital care. Magical thinking was evaluated with the Spiritual Acceptance Scale (e.g., beliefs in telepathy, miracles, mystical events, or sixth sense) of the Temperament and Character Inventory in 1997, 2001, and 2012 (participants were 20-50-year-olds). We found that, among those who did not develop non-affective psychotic disorders, high PRS predicted higher magical thinking in adulthood (p = 0.001). Further, PRS predicted different developmental courses: a low PRS predicted a steady decrease in magical thinking from age 20 to 50 years, while in individuals with high PRS the decrease in magical thinking ceased in middle age so that their level of magical thinking remained higher than expected for that age. These findings remained when controlling for sex, childhood family environment, and adulthood socioeconomic factors. In conclusion, if high PRS does not lead to a non-affective psychotic disorder, it predicts milder forms of deviant thinking such as elevated magical thinking in adulthood, especially in middle age. The finding enhances our understanding of different outcomes of high genetic psychosis risk.

Integrating trauma, self-disturbances, cognitive biases, and personality into a model for the risk of psychosis: a longitudinal study in a non-clinical sample

The hypothesis of the psychosis continuum enables to study the mechanisms of psychosis risk not only in clinical samples but in non-clinical as well. The aim of this longitudinal study was to investigate self-disturbances (SD), a risk factor that has attracted substantial interest over the last two decades, in combination with trauma, cognitive biases and personality, and to test whether SD are associated with subclinical positive symptoms (PS) over a 12-month follow-up period. Our study was conducted in a non-clinical sample of 139 Polish young adults (81 females, age M = 25.32, SD = 4.51) who were selected for frequent experience of subclinical PS. Participants completed self-report questionnaires for the evaluation of SD (IPASE), trauma (CECA.Q), cognitive biases (DACOBS) and personality (TCI), and were interviewed for subclinical PS (CAARMS). SD and subclinical PS were re-assessed 12 months after baseline measurement. The hypothesized model for psychosis risk was tested using path analysis. The change in SD and subclinical PS over the 12-month period was investigated with non-parametric equivalent of dependent sample t-tests. The models with self-transcendence (ST) and harm avoidance (HA) as personality variables were found to be well-fitted and explained 34% of the variance in subclinical PS at follow-up. Moreover, we found a significant reduction of SD and subclinical PS after 12 months. Our study suggests that combining trauma, cognitive biases, SD and personality traits such as ST and HA into one model can enhance our understanding of appearance as well as maintenance of subclinical PS.

Temperament-Character Traits and Attitudes Toward Premature Ejaculation in 4 Types of Premature Ejaculation

BACKGROUND

Although temperament-character traits and attitudes toward premature ejaculation (PE) are known to be associated with PE, it is of great significance to study them in PE. Moreover, few studies have evaluated these traits and attitudes in the new classification of 4 subtypes of PE.

AIM

We investigated the temperament-character traits and attitudes toward PE in 4 types of PE and their associations with PE.

METHODS

Between December 2018 and December 2019, we conducted a survey in our hospital, and enrolled 350 men who complained of PE and 252 men without any complaint of PE. Temperament-character traits and attitudes toward PE were independently assessed by the Temperament and Character Inventory-Revised and several targeted questions, respectively. The Index of Premature Ejaculation (IPE) was used to evaluate ejaculation control, sexual life satisfaction, and distress caused by PE.

OUTCOMES

The outcomes included differences of temperament-character traits and attitudes toward PE among 2 groups and their associations with PE.

RESULTS

Of the 2 groups, men with PE complaints had lower novelty seeking/self-transcendence (NS/ST) scores and higher harm avoidance (HA) scores vs men without any complaints of PE. Among the 4 types of PE, men with variable PE had the highest score of HA and lowest score of NS; the lowest score of ST was recorded in men with lifelong PE. Additionally, the total and subdomain scores of IPE in men with subjective PE were higher than the other subtypes of PE. After adjusting for age, positive correlations were observed in HA score and total and subdomain scores of IPE, whereas the inverse was true corresponding to NS and ST.

CLINICAL IMPLICATIONS

The current study has provided a new perspective for understanding the impact of psychological factors on PE.

STRENGTHS & LIMITATIONS

This is the first study to systematically assess the effects of personality traits and attitudes on PE, especially among the 4 types of PE. The main drawback is that the generalizability of this study may be limited by the fact that it was conducted in a single cultural/societal background.

CONCLUSION

Men who complained of PE tended to react with indifference or rejection to novelty, tended to feel unsatisfied, cannot effectively adapt to changes in the surrounding environment, and tended to avoid situations involving risk. These characteristics could lead to their becoming disheartened when faced with PE. Furthermore, the attitude of men with PE reflects the needs of the patient during treatment from one aspect. Gao P, Gao J Wang Y, et al. Temperament-Character Traits and Attitudes Toward Premature Ejaculation in 4 Types of Premature Ejaculation. J Sex Med 2021;18:72-82.

Personality Traits as Markers of Psychosis Risk in Kenya: Assessment of Temperament and Character

Specific personality traits have been proposed as a schizophrenia-related endophenotype and confirmed in siblings at risk for psychosis. The relationship of temperament and character with psychosis has not been previously investigated in Africa. The study was conducted in Kenya, and involved participants at clinical high-risk (CHR) for psychosis (n = 268) and controls (n = 251), aged 15–25 years. CHR status was estimated using the Structured Interview of Psychosis-Risk Syndromes (SIPS) and the Washington Early Psychosis Center Affectivity and Psychosis (WERCAP) Screen. Student’s t-tests were used to assess group differences on the Temperament and Character Inventory (TCI). Neurocognitive functioning, stress severity, and substance use were correlated with the TCI, correcting for psychosis severity. CHR participants were more impulsive (ie, higher novelty seeking [NS]) and asocial (ie, lower reward dependence) than controls. They were also more schizotypal (ie, high self-transcendence [ST] and lower self-directedness [SD] and cooperativeness [CO] than controls). CO was related to logical reasoning, abstraction, and verbal memory. Stress severity correlated with high HA and schizotypal character traits. Lifetime tobacco use was related to NS, and lifetime marijuana use to high NS, low SD and high ST. Temperament and character of Kenyan CHR youth is similar to that observed in schizophrenia. Psychosis risk in Kenya is associated with impulsive, asocial, and schizotypal traits. CHR adolescents and young adults with schizophrenia-specific personality traits may be most at risk for developing a psychotic disorder and to require early intervention to improve outcomes.

The role of personality in posttraumatic stress disorder, trait resilience, and quality of life in people exposed to the Kiss nightclub fire

Objective

To evaluate the relationship among personality (according to Cloninger’s psychobiological model), posttraumatic stress disorder (PTSD) symptoms, trait resilience and quality of life (QoL) in people who were exposed to the Kiss nightclub fire.

Methods

188 participants were assessed with the Posttraumatic Checklist–civilian version (PCL-C), the Resilience Scale (RS), the Temperament and Character Inventory (TCI), the World Health Organization Quality of Life–Bref (WHOQOL-Bref), and the WHOQOL-100 Spirituality, religiousness, and personal beliefs (WHOQOL-100-SRPB). Data were analyzed in a dimensional approach, with correlation analysis, multiple linear regression and Structural Equation Modeling (SEM), with PCL-C, RS, and WHOQOL-Bref dimensions as dependent variables.

Results

Multiple linear regression showed that PTSD symptoms were predicted by harm avoidance (β = .34, p < .001), self-directedness (β = -.28, p < .01), and self-transcendence (β = .24, p < .01). Trait resilience was predicted by harm avoidance (β = -.38, p < .01), self-directedness (β = .20, p < .05), and self-transcendence (β = .18, p < .05). Also, PTSD symptoms had considerable negative effect on all dimensions of QoL. Self-transcendence was a positive predictor of subjective and spiritual QoL. SEM showed that QoL was predicted by PTSD symptoms (β = -.52, p < .001), trait resilience (β = .30, p < .001), cooperativeness (β = .135, p = 0.40), and self-directedness (β = .27, p < .01). The effect of self-directedness on QoL was mediated by PTSD symptoms and trait resilience. PTSD symptoms also mediated the relationship between trait resilience and QoL, and RS mediated the relationship of personality and PTSD symptoms.

Conclusion

The study gives insights on prediction of PTSD severity, trait resilience and QoL from temperament and character traits, in a sample of people exposed to the Kiss nightclub fire. Harm avoidance was the most influent trait on PTSD symptoms and trait resilience. Self-directedness was the most import trait related to QoL, still that it was more related to PTSD severity than personality traits. Self-transcendence had positive effects on both PTSD symptoms and trait resilience, indicating a coping style that may coexist with psychopathology.

Relationship of self-transcendence traits with in vivo dopamine D2/3 receptor availability and functional connectivity: An [18 F]fallypride PET and fMRI study

Genetic research has implicated dopamine neurotransmission in the expression of the self-transcendence trait in humans. However, molecular imaging of dopaminergic markers is undocumented in relation to this personality trait. In this multimodal imaging study, we first investigated the relationship between the self-transcendence trait and in vivo dopamine D_2/3 receptor availability using [¹⁸ F]fallypride positron emission tomography (PET). We next conducted seed-based functional connectivity analyses using resting-state functional magnetic resonance imaging (rs-fMRI) data with regions derived from the PET analysis as seeds to explore the functional significance of D_2/3 receptor availability foci associated with the self-transcendence trait. Twenty-one healthy subjects underwent high-resolution PET with [¹⁸ F]fallypride and a subset of 18 subjects also completed 3-Tesla rs-fMRI. The Temperament and Character Inventory was used to measure the self-transcendence trait. A voxel-based whole brain analysis revealed that the [¹⁸ F]fallypride binding potential (BP_ND ) within the cluster of the left insula was significantly positively correlated with self-transcendence trait scores. A region-of-interest analysis also showed a significant positive correlation between self-transcendence and [¹⁸ F]fallypride BP_ND in the left insula. The exploratory [¹⁸ F]fallypride BP_ND seed-based rs-fMRI analysis showed that the functional connectivity from the left insula seed to the prefrontal cortices (including the inferior frontal region) was negatively associated with self-transcendence trait scores. The results of the present study suggest that D_2/3 receptor-mediated neurotransmission in the left insula may constitute a significant neurobiological factor in the self-transcendence trait. The negative associations between BP_ND seed-based functional connectivity and self-transcendence trait scores may suggest reduced prefrontal control in this personality trait.

Serotonin 5-HT1A receptor binding and self-transcendence in healthy control subjects-a replication study using Bayesian hypothesis testing

Objective

A putative relationship between markers for the serotonin system and the personality scale self-transcendence (ST) and its subscale spiritual acceptance (SA) has been demonstrated in a previous PET study of 5-HT_1A receptor binding in healthy control subjects. The results could however not be replicated in a subsequent PET study at an independent centre. In this study, we performed a replication of our original study in a larger sample using Bayesian hypothesis testing to evaluate relative evidence both for and against this hypothesis.

Methods

Regional 5-HT_1A receptor binding potential (BP_ND) was examined in 50 healthy male subjects using PET with the radioligand [¹¹C]WAY100635. 5-HT_1Aavailability was calculated using the simplified reference tissue model (SRTM) yielding regional BP_ND. ST and SA were measured using the Temperament and Character Inventory (TCI) questionnaire. Correlations between ST/SA scores and 5-HT_1ABP_ND in frontal cortex, hippocampus and raphe nuclei were examined by calculation of default correlation Bayes factors (BFs) and replication BFs.

Results

There were no significant correlations between 5-HT_1A receptor binding and ST/SA scores. Rather, five of six replication BFs provided moderate to strong evidence for no association between 5-HT_1A availability and ST/SA, while the remaining BF provided only weak evidence.

Conclusion

We could not replicate our previous findings of an association between 5-HT_1A availability and the personality trait ST/SA. Rather, the Bayesian analysis provided evidence for a lack of correlation. Further research should focus on whether other components of the serotonin system may be related to ST or SA. This study also illustrates how Bayesian hypothesis testing allows for greater flexibility and more informative conclusions than traditional p-values, suggesting that this approach may be advantageous for analysis of molecular imaging data.

Relationship between executive function, attachment style, and psychotic like experiences in typically developing youth

Psychotic like experiences (PLE's) are common in the general population, particularly during adolescence, which has generated interest in how PLE's emerge, and the extent to which they reflect either risk for, or resilience to, psychosis. The "attachment-developmental-cognitive" (ADC) model is one effort to model the effect of risk factors on PLEs. The ADC model proposes attachment insecurity as an early environmental insult that can contribute to altered neurodevelopment, increasing the likelihood of PLE's and psychosis. In particular, early-life attachment disruptions may negatively impact numerous aspects of executive function (EF), including behavioral inhibition and emotion regulation. Yet despite the relationship of disrupted attachment to EF impairments, no studies have examined how these factors may combine to contribute to PLE's in adolescents. Here, we examined the relative contributions of daily-life EF and attachment difficulties (avoidance and anxiety) to PLEs in typically developing youth (N=52; ages 10-21). We found that EF deficits and high attachment insecurity both accounted for a significant proportion of the variance in PLE's, and interacted to predict PLE manifestation. Specifically, positive PLEs were predicted by greater trouble monitoring behavioral impact, less difficulty completing tasks, greater difficulty regulating emotional reactions, greater difficulty controlling impulses and higher attachment anxiety. Negative PLEs were predicted by greater difficulty in alternating attention, transitioning across situations, and regulating emotional reactions as well as higher attachment anxiety. These results are consistent with the ADC model, providing evidence that early-life attachment disruptions may impact behavioral regulation and emotional control, which together may contribute to PLEs.

Protective Factors for Psychotic Symptoms Among Poly-victimized Children

BACKGROUND

Experiencing victimization in early life has been repeatedly shown to be associated with the emergence of psychotic symptoms in childhood. However, most victimized children do not develop psychotic symptoms and why this occurs is not fully understood. This study investigated which individual, family-level, and wider community characteristics were associated with an absence of psychotic symptoms among children at risk for psychosis by virtue of their exposure to multiple victimization experiences (poly-victimization).

METHODS

Participants were from the Environmental Risk Longitudinal Twin Study, a nationally representative cohort of 2232 UK-born twins. Exposure to maltreatment, bullying and domestic violence prior to age 12 was determined from interviews with mothers, children, and observations by research workers at ages 5, 7, 10, and 12. Children were interviewed about psychotic symptoms at age 12. Protective factors were measured at ages 5, 7, 10, and 12.

RESULTS

Childhood poly-victimization was associated with age-12 psychotic symptoms (OR = 4.61, 95% CI 2.82-7.52), but the majority of poly-victimized children did not report symptoms (80.7%). Having a relatively high IQ, more positive atmosphere at home, and higher levels of neighborhood social cohesion were found to be protective against childhood psychotic symptoms among poly-victimized children and also in the whole sample. However, "protected" poly-victimized children displayed elevated levels of other mental health problems compared to nonvictimized children.

CONCLUSIONS

Children's characteristics, family context, and the wider community were all found to protect children from developing early psychotic symptoms, even when they were victimized multiple times. These findings indicate targets for multilevel preventive interventions.

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.

Investigating the Impact of a Genome-Wide Supported Bipolar Risk Variant of MAD1L1 on the Human Reward System

Recent genome-wide association studies have identified MAD1L1 (mitotic arrest deficient-like 1) as a susceptibility gene for bipolar disorder and schizophrenia. The minor allele of the single-nucleotide polymorphism (SNP) rs11764590 in MAD1L1 was associated with bipolar disorder. Both diseases, bipolar disorder and schizophrenia, are linked to functional alterations in the reward system. We aimed at investigating possible effects of the MAD1L1 rs11764590 risk allele on reward systems functioning in healthy adults. A large homogenous sample of 224 young (aged 18-31 years) participants was genotyped and underwent functional magnetic resonance imaging (fMRI). All participants performed the 'Desire-Reason Dilemma' paradigm investigating the neural correlates that underlie reward processing and active reward dismissal in favor of a long-term goal. We found significant hypoactivations of the ventral tegmental area (VTA), the bilateral striatum and bilateral frontal and parietal cortices in response to conditioned reward stimuli in the risk allele carriers compared with major allele carriers. In the dilemma situation, functional connectivity between prefrontal brain regions and the ventral striatum was significantly diminished in the risk allele carriers. Healthy risk allele carriers showed a significant deficit of their bottom-up response to conditioned reward stimuli in the bilateral VTA and striatum. Furthermore, functional connectivity between the ventral striatum and prefrontal areas exerting top-down control on the mesolimbic reward system was reduced in this group. Similar alterations in reward processing and disturbances of prefrontal control mechanisms on mesolimbic brain circuits have also been reported in bipolar disorder and schizophrenia. Together, these findings suggest the existence of an intermediate phenotype associated with MAD1L1.

Disintegration as an Additional Trait in the Psychobiological Model of Personality

Abstract. This meta-analytic study investigates the relations between Disintegration-like phenomena (i.e., various aspects of symptomatology with the prefix “schizo-,” both at the clinical and the subclinical level) and the traits of the Psychobiological Model of Personality (PBMP). The empirically based benchmark for assuming the distinctness of the trait Disintegration was .30. The sample included 26 manuscripts with 30 studies and 424 effect sizes. By computing inverse sampling variance weighted mean correlation coefficients under a random-effects assumption, the following associations were found between Disintegration and Harm Avoidance, Novelty Seeking, Reward Dependence, Persistence, Self-Directedness, Cooperativeness, and Self-Transcendence: .23, .04, −.15, −.02, −.23, −.16, and .17, respectively. Two variables were found to moderate the Disintegration-Self-Transcendence correlation. Despite the theoretical expectation and some empirical evidence that Self-Transcendence (and other character traits) should capture variations in Disintegration-like phenomena, our results suggest that schizo-type phenomena are not adequately covered by the PBMP.

Heritability and Familiality of Temperament and Character Dimensions in Korean Families with Schizophrenic Linkage Disequilibrium

Objective

Categorical syndromes such as schizophrenia may represent complexes of many continuous psychological structural phenotypes along several dimensions of personality development/degeneration. The present study investigated the heritability and familiality of personality dimensions in Korean families with schizophrenic linkage disequilibrium (LD).

Methods

We recruited 179 probands (with schizophrenia) as well as, whenever possible, their parents and siblings. We used the Temperament and Character Inventory (TCI) to measure personality and symptomatic dimensions. The heritability of personality dimensions in a total of 472 family members was estimated using Sequential Oligogenic Linkage Analysis Routines (SOLAR). To measure familiality, we compared the personality dimensions of family members with those of 336 healthy unrelated controls using analysis of variance (ANOVA) analysis.

Results

Three of the seven TCI variables were significantly heritable and were included in subsequent analyses. The three groups (control, unaffected first-degree relative, case) were found to significantly differ from one another, with the expected order of average group scores, for all heritable dimensions.

Conclusion

Despite several study limitations with respect to family recruitment and phenotyping, our results show that aberrations in several personality dimensions related to genetic-environment coactions or interactions may underlie the complexity of the schizophrenic syndrome.

Psychometric properties of the Greek TCI-R and its clinical correlates: schizotypy and the self-regulation of affective and cognitive functioning

Background. The revised Temperament and Character Inventory (TCI-R) measures Cloninger’s psychobiological model of personality. The average effects of individual temperament and character traits have been associated with schizotypy and with impaired regulation of affect and cognition. We extended prior research by testing predictions about the association of specific multidimensional configurations of temperament and character traits on schizotypy, affect balance, and self-perceived cognitive functioning.

Method. A well-educated sample of native Greeks (N = 483), completed a new Greek translation of the TCI-R, as well as the Schizotypal Personality Questionnaire (SPQ), the Positive/Negative Affect Schedule (PANAS) and the Cognitive Failures Questionnaire (CFQ). The factor structure of the TCI-R was examined with exploratory and confirmatory tests. Associations between reported measures were examined with correlational and regression analyses.

Results. The TCI-R had good psychometric properties as expected from studies in other countries. As predicted, specific configurations of temperament and character were associated with schizotypy, negative affect balance, and cognitive lapses. The “Borderline/Explosive temperament” (high Novelty Seeking, high Harm Avoidance, low Reward Dependence), “Schizotypal/Disorganized character” (low Self-directedness, low Cooperativeness, high Self-transcendence), and “Low Ego Strength/Fragile” profile (high Harm Avoidance, low Persistence, low Self-Directedness) were each strongly associated with higher stereotypy, negative affect balance (low positive affect and high negative affect), and subjective cognitive lapses compared to their contrast groups.

Discussion. Multidimensional TCI profiles are strongly related to individual differences in schizotypy and self-reported regulation of affect and cognition. The Greek translation of the TCI-R is psychometrically sound and useful for clinical assessment and research.

The relationship between temperament and character and psychotic-like experiences in healthy children and adolescents

BACKGROUND

Prior work by our group identified personality profiles associated with psychotic-like experiences (PLE's) in healthy adults that were strikingly similar to those found in schizophrenia patients, with the exception of two key differences. Specifically, higher levels of PLE's were linked to higher persistence and cooperativeness, suggesting that these characteristics might represent personality-based resilience factors. Notably, age and personality were significantly correlated in these data, raising questions about whether healthy children and adolescents would show similar results. To date, no study has examined personality profiles associated with both positive and negative PLE's in healthy children and adolescents using Cloninger's Temperament and Character Inventory (TCI). Thus, this study examined the relationship between TCI dimensions and PLE's in healthy children and adolescents.

METHOD

The TCI and the Community Assessment of Psychic Experiences (CAPE) were administered to 123 healthy children and adolescents aged 8-18. Multiple regression models were used to examine personality dimensions associated with overall severity of PLE's as well as severity of positive and negative PLE's separately.

RESULTS

Positive, negative, and overall PLE severity were all associated with a personality pattern of higher harm avoidance and lower self-directedness. Negative PLE severity was also associated with lower persistence.

CONCLUSIONS

Personality correlates of PLE's in healthy children and adolescents were largely consistent with our past work on PLE's in healthy adults. However, our previously identified resilience factors were notably absent in this sample. These findings may suggest that these personality characteristics have not yet crystallized or emerged to aid in coping with PLE's.

Dysfunctional meta-cognitive beliefs mediate the relation between temperament traits and hallucination-proneness in non-clinical population

We investigated whether dysfunctional metacognitive beliefs (negative beliefs about uncontrollability and danger of thoughts) mediate the relationship between temperamental characteristics of behavior and hallucinatory-like experiences in healthy subjects (n=137). Our analyses showed that four temperamental traits (emotional reactivity, perseveration, endurance and briskness) were mediated by negative beliefs about uncontrollability and danger of thoughts in relation to hallucination proneness. Our research tentatively suggests that temperament affects hallucination proneness via metacognition.

Examining the Psychosis Continuum

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

Grey matter, an endophenotype for schizophrenia? A voxel-based morphometry study in siblings of patients with schizophrenia

BACKGROUND

Grey matter, both volume and concentration, has been proposed as an endophenotype for schizophrenia given a number of reports of grey matter abnormalities in relatives of patients with schizophrenia. However, previous studies on grey matter abnormalities in relatives have produced inconsistent results. The aim of the present study was to examine grey matter differences between controls and siblings of patients with schizophrenia and to examine whether the age, genetic loading or subclinical psychotic symptoms of selected individuals could explain the previously reported inconsistencies.

METHODS

We compared the grey matter volume and grey matter concentration of healthy siblings of patients with schizophrenia and healthy controls matched for age, sex and education using voxel-based morphometry (VBM). Furthermore, we selected subsamples based on age (< 30 yr), genetic loading and subclinical psychotic symptoms to examine whether this would lead to different results.

RESULTS

We included 89 siblings and 69 controls in our study. The results showed that siblings and controls did not differ significantly on grey matter volume or concentration. Furthermore, specifically selecting participants based on age, genetic loading or subclinical psychotic symptoms did not alter these findings.

LIMITATIONS

The main limitation was that subdividing the sample resulted in smaller samples for the subanalyses. Furthermore, we used MRI data from 2 different scanner sites.

CONCLUSION

These results indicate that grey matter measured through VBM might not be a suitable endophenotype for schizophrenia.

Temperament and character dimensions assessed in general population, in individuals with psychoactive substance dependence and in young male conscripts

BACKGROUND

In this work we consider Cloninger's psychobiological model, which measures two dimensions of personality: character and temperament. Temperament refers to the biological basis of personality and its characteristics, while character refers to an individual's attitudes towards own self, towards humanity and as part of the universe.

METHODS

The Temperament and Character Inventory-Revised-140 (TCI-R-140) was administered to 3 divergent samples: a general population sample, a sample of male conscripts and a sample of individuals attending a substance abuse rehabilitation programme. Score differences among the three samples were assessed controlling for age and gender and reliability coefficients are reported. The latent structure was studied in all samples, using exploratory and confirmatory factor analysis methods (EFA and CFA respectively).

RESULTS

The proposed structure was partially replicated via EFA. CFA however indicated less than satisfactory fit, as in previously reported results. To improve the fit, the path diagram was augmented to account for multiple factor complexity, as suggested by the EFA results in all samples. While retaining the original seven-factor structure, the augmented model provided adequate fit. The consistency of the inventory was satisfactory in all samples. Evidence for the construct validity was found in relation to aggression.

CONCLUSIONS

This is the first study to conclude in adequate fit, after allowing for the indicators to load on more than one factor within each dimension. While cross-national differences apply, our results were similar (when comparable) with previously reported ones in the literature.

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.