Deconstructing sub-clinical psychosis into latent-state and trait variables over a 30-year time span

Comparing the latent state-trait structure of the PANSS in cariprazine-medicated and placebo-controlled patients with acute schizophrenia

After over a hundred years of research, the question whether the symptoms of schizophrenia are rather trait-like (being a relatively stable quality of individuals) or state-like (being substance to change) is still unanswered. To assess the trait and the state component in patients with acute schizophrenia, one group receiving antipsychotic treatment, the other not. Data from four phase II/III, 6-week, randomized, double-blind, placebo-controlled trials of similar design that included patients with acute exacerbation of schizophrenia were pooled. In every trial, one treatment group received a third-generation antipsychotic, cariprazine, and the other group placebo. To assess symptoms of schizophrenia, the Positive and Negative Symptom Scale (PANSS) was applied. Further analyses were conducted using the five subscales as proposed by Wallwork and colleagues. A latent state-trait (LST) model was developed to estimate the trait and state components of the total variance of the observed scores. All symptom dimensions behaved more in a trait-like manner. The proportions of all sources of variability changed over the course of the observational period, with a bent around weeks 3 and 4. Visually inspected, no major differences were found between the two treatment groups regarding the LST structure of symptom dimensions. This high proportion of inter-individual stability may represent an inherent part of symptomatology that behaves independently from treatment status.

Latent state-trait structure of BPRS subscales in clinical high-risk state and first episode psychosis

To investigate the longitudinal latent state-trait structure of the different dimensions of psychosis symptoms in clinical high-risk state (CHRS) and first episode psychosis (FEP) individuals over a one year time-span. This paper examines if the symptom clusters Positive Symptoms, Negative Symptoms, Affectivity, Resistance, Activation, and Excitement according to the Brief Psychiatric Rating Scale (BPRS) differ in their trait and state characters in 196 CHRS and 131 FEP individuals. Statistical analysis was performed using latent state-trait analysis. On average, trait differences accounted for 72.2% of Positive Symptoms, 81.1% of Negative Symptoms, 57.0% of Affectivity, and 69.2% of Activation, whereas 15.0% of the variance of Resistance and 13.2% of the variance of Excitement were explained by trait differences. Explorative analyses showed a trait components' increase of 0.408 in Positive Symptoms from baseline up to the 9th month and an increase of 0.521 in Affectivity from baseline up to the 6th month. Negative Symptoms had the highest trait component levels of all subscales between baseline and 6 months. The finding that an increasing proportion of psychosis symptoms is persisting over time underlines the importance of early intervention programs in individuals with psychotic disorders.

Brain structural correlates of schizotypal signs and subclinical schizophrenia nuclear symptoms in healthy individuals

BACKGROUND

Subclinical psychotic-like experiences (PLE), resembling key symptoms of psychotic disorders, are common throughout the general population and possibly associated with psychosis risk. There is evidence that such symptoms are also associated with structural brain changes.

METHODS

In 672 healthy individuals, we assessed PLE and associated distress with the symptom-checklist-90R (SCL-90R) scales 'schizotypal signs' (STS) and 'schizophrenia nuclear symptoms' (SNS) and analysed associations with voxel- and surfaced-based brain structural parameters derived from structural magnetic resonance imaging at 3 T with CAT12.

RESULTS

For SNS, we found a positive correlation with the volume in the left superior parietal lobule and the precuneus, and a negative correlation with the volume in the right inferior temporal gyrus [p < 0.05 cluster-level Family Wise Error (FWE-corrected]. For STS, we found a negative correlation with the volume of the left and right precentral gyrus (p < 0.05 cluster-level FWE-corrected). Surface-based analyses did not detect any significant clusters with the chosen statistical threshold of p < 0.05. However, in exploratory analyses (p < 0.001, uncorrected), we found a positive correlation of SNS with gyrification in the left insula and rostral middle frontal gyrus and of STS with the left precuneus and insula, as well as a negative correlation of STS with gyrification in the left temporal pole.

CONCLUSIONS

Our results show that brain structures in areas implicated in schizophrenia are also related to PLE and its associated distress in healthy individuals. This pattern supports a dimensional model of the neural correlates of symptoms of the psychotic spectrum.

Nonclinical psychotic-like experiences and schizotypy dimensions: Associations with hippocampal subfield and amygdala volumes

Schizotypy and psychotic-like experiences (PLE) form part of the wider psychosis continuum and may have brain structural correlates in nonclinical cohorts. This study aimed to compare the effects of differential schizotypy dimensions, PLE, and their interaction on hippocampal subfields and amygdala volumes in the absence of clinical psychopathology. In a cohort of 367 psychiatrically healthy individuals, we assessed schizotypal traits using the Oxford-Liverpool Inventory of Life Experiences (O-LIFE) and PLE using the short form of the Prodromal Questionnaire (PQ-16). Based on high-resolution structural MRI scans, we used automated segmentation to estimate volumes of limbic structures. Sex and total intracranial volume (Step 1), PLE and schizotypy dimensions (Step 2), and their interaction terms (Step 3) were entered as regressors for bilateral amygdala and hippocampal subfield volumes in hierarchical multiple linear regression models. Positive schizotypy, but not PLE, was negatively associated with left amygdala and subiculum volumes. O-LIFE Impulsive Nonconformity, as well as the two-way interaction between positive schizotypy and PLE, were associated with larger left subiculum volumes. None of the estimators for right hemispheric hippocampal subfield volumes survived correction for multiple comparisons. Our findings support differential associations of hippocampus subfield volumes with trait dimensions rather than PLE, and support overlap and interactions between psychometric positive schizotypy and PLE. In a healthy cohort without current psychosis risk syndromes, the positive association between PLE and hippocampal subfield volume occurred at a high expression of positive schizotypy. Further studies combining stable, transient, and genetic parameters are required.

The Interplay Between Postsynaptic Striatal D2/3 Receptor Availability, Adversity Exposure and Odd Beliefs: A [11C]-Raclopride PET Study

BACKGROUND

Between unaffected mental health and diagnosable psychiatric disorders, there is a vast continuum of functioning. The hypothesized link between striatal dopamine signaling and psychosis has guided a prolific body of research. However, it has been understudied in the context of multiple interacting factors, subclinical phenotypes, and pre-postsynaptic dynamics.

METHOD

This work investigated psychotic-like experiences and D2/3 dopamine postsynaptic receptor availability in the dorsal striatum, quantified by in vivo [11C]-raclopride positron emission tomography, in a sample of 24 healthy male individuals. Additional mediation and moderation effects with childhood trauma and key dopamine-regulating genes were examined.

RESULTS

An inverse relationship between nondisplaceable binding potential and subclinical symptoms was identified. D2/3 receptor availability in the left putamen fully mediated the association between traumatic childhood experiences and odd beliefs, that is, inclinations to see meaning in randomness and unfounded interpretations. Moreover, the effect of early adversity was moderated by a DRD2 functional variant (rs1076560). The results link environmental and neurobiological influences in the striatum to the origination of psychosis spectrum symptomology, consistent with the social defeat and diathesis-stress models.

CONCLUSIONS

Adversity exposure may affect the dopamine system as in association with biases in probabilistic reasoning, attributional style, and salience processing. The inverse relationship between D2/3 availability and symptomology may be explained by endogenous dopamine occupying the receptor, postsynaptic compensatory mechanisms, and/or altered receptor sensitivity. This may also reflect a cognitively stabilizing mechanism in non-help-seeking individuals. Future research should comprehensively characterize molecular parameters of dopamine neurotransmission along the psychosis spectrum and according to subtype profiling.

Cortical Gyrification, Psychotic-Like Experiences, and Cognitive Performance in Nonclinical Subjects

BACKGROUND

Psychotic-like experiences (PLE) are present in nonclinical populations, yet their association with brain structural variation, especially markers of early neurodevelopment, is poorly understood. We tested the hypothesis that cortical surface gyrification, a putative marker of early brain development, is associated with PLE in healthy subjects.

METHODS

We analyzed gyrification from 3 Tesla MRI scans (using CAT12 software) and PLE (positive, negative, and depressive symptom dimensions derived from the Community Assessment of Psychic Experiences, CAPE) in 103 healthy participants (49 females, mean age 29.13 ± 9.37 years). A subsample of 63 individuals completed tasks from the Wechsler Adult Intelligence Scale and Controlled Oral Word Association Test. Estimated IQ and a composite neuropsychological score were used to explore mediation pathways via cognition.

RESULTS

Positive PLE distress was negatively associated with gyrification of the left precuneus. PLE depression dimension showed a negative association with gyrification in the right supramarginal and temporal region. There was no significant mediating effect of cognition on these associations.

CONCLUSION

Our results support a neurobiological psychosis spectrum, for the first time linking an early developmental imaging marker (rather than volume) to dimensional subclinical psychotic symptoms. While schizophrenia risk, neurodevelopment, and cognitive function might share genetic risk factors, additional mediation analyses did not confirm a mediating effect of cognition on the gyrification-psychopathology correlation.

Checking the predictive accuracy of basic symptoms against ultra high-risk criteria and testing of a multivariable prediction model: Evidence from a prospective three-year observational study of persons at clinical high-risk for psychosis

Background:

The aim of this study was to critically examine the prognostic validity of various clinical high-risk (CHR) criteria alone and in combination with additional clinical characteristics.

Methods:

A total of 188 CHR positive persons from the region of Zurich, Switzerland (mean age 20.5 years; 60.2% male), meeting ultra high-risk (UHR) and/or basic symptoms (BS) criteria, were followed over three years. The test battery included the Structured Interview for Prodromal Syndromes (SIPS), verbal IQ and many other screening tools. Conversion to psychosis was defined according to ICD-10 criteria for schizophrenia (F20) or brief psychotic disorder (F23).

Results:

Altogether n = 24 persons developed manifest psychosis within three years and according to Kaplan–Meier survival analysis, the projected conversion rate was 17.5%. The predictive accuracy of UHR was statistically significant but poor (area under the curve [AUC] = 0.65, P < .05), whereas BS did not predict psychosis beyond mere chance (AUC = 0.52, P = .730). Sensitivity and specificity were 0.83 and 0.47 for UHR, and 0.96 and 0.09 for BS. UHR plus BS achieved an AUC = 0.66, with sensitivity and specificity of 0.75 and 0.56. In comparison, baseline antipsychotic medication yielded a predictive accuracy of AUC = 0.62 (sensitivity = 0.42; specificity = 0.82). A multivariable prediction model comprising continuous measures of positive symptoms and verbal IQ achieved a substantially improved prognostic accuracy (AUC = 0.85; sensitivity = 0.86; specificity = 0.85; positive predictive value = 0.54; negative predictive value = 0.97).

Conclusions:

We showed that BS have no predictive accuracy beyond chance, while UHR criteria poorly predict conversion to psychosis. Combining BS with UHR criteria did not improve the predictive accuracy of UHR alone. In contrast, dimensional measures of both positive symptoms and verbal IQ showed excellent prognostic validity. A critical re-thinking of binary at-risk criteria is necessary in order to improve the prognosis of psychotic disorders.

Heritability and familiality of psychopathologic dimensions in Korean families with schizophrenia

AIM

Categorical syndromes such as schizophrenia could be a combination of many continuous mental structure phenotypes including several personality development/degeneration dimensions. This study investigated the heritability and familiality of symptom check list (SCL) psychopathologic dimensions in Korean schizophrenia linkage disequilibrium families.

METHOD

We recruited 204 probands (with schizophrenia) with their parents and siblings whenever possible. We used the SCL questionnaire to measure psychopathologic dimensions. The heritability of symptomatic dimensions in 543 family members was estimated using Sequential Oligogenic Linkage Analysis Routines (SOLAR). Psychopathologic dimensions in the 543 family members were compared with those in 307 healthy unrelated controls to measure familiality on using analysis of variance (ANOVA) analysis.

RESULTS

Five of the nine SCL variables were significantly heritable and were included in the subsequent analyses. The three groups (control, unaffected first-degree relative, schizophrenia patient) were found to be significantly different with regard to the expected order of average group scores for all heritable dimensions.

CONCLUSION

Aberrations in several symptomatic dimensions could contribute to the complexity of schizophrenia syndrome as a result of genetic-environment coaction or interaction in spite of some limitations (recruited family, phenotyping).

Borderline Personality Pathology in an At Risk Mental State Sample

Introduction: Transient psychotic symptoms in patients with borderline personality disorder seem to be similar to those in patients with psychotic disorders. Especially in the field of early detection of psychosis, this might lead to individuals with borderline personality disorder being wrongly classified as subjects at risk for developing a manifest psychosis. The aim of the present study was to investigate the occurrence of borderline symptoms in a sample of subjects at risk for psychosis as well as possible effects on the transition rate. Methods: Seventy help-seeking individuals of an early psychosis recognition center were additionally examined for borderline symptoms by the borderline symptom checklist. Results: We found a significant correlation between borderline symptomatology and positive symptoms assessed by the structured interview for prodromal symptoms. There were no associations between basic symptoms for psychosis and borderline symptoms. In addition, there was no influence of borderline symptomatology on the rate of transition into a manifest schizophrenic disease. Summary: In conclusion, borderline personality disorder should not be an exclusion criterion for the screening for psychosis or for an early intervention treatment. On the other hand, not every patient with borderline personality disorder, (especially those not suffering from hallucinations, unusual thought content, or persecutory ideas) should automatically be screened for the risk of developing a psychotic disorder.

Articulation and testing of a personality-centred model of psychopathology: evidence from a longitudinal community study over 30 years

Advances in psychopathological research advocate a personality-centred model of common mental disorders (CMD). We tested four hypotheses to test such a model. First, personality relates to critical life events; second, both personality and critical life events relate to CMD; third, interaction effects between personality and critical life events relate to CMD; fourth, neuroticism explains the majority of variance in psychopathology. We analysed data (n = 453) based on seven semi-structured interviews from a longitudinal epidemiologic cohort study over 30 years spanning years 1979 (age 20) to 2008 (age 50). CMD and critical life events were assessed seven times between 1979 and 2008 and personality domains of neuroticism, extraversion and aggressiveness in 1988 and 1993. Aggressiveness and neuroticism related to partnership rupture and job loss. Neuroticism related significantly to major depression, anxiety disorders, substance-use disorders (SUD) and severity of psychopathology. Both partnership rupture and job loss related to major depression and severity of psychopathology, but not to anxiety disorder or SUD. An interaction effect between neuroticism and partnership rupture pointed towards significantly increased SUD prevalence. All associations held when additionally adjusted for childhood adversity and familial socio-economic status. According to a pseudo-R ², neuroticism explained 51% of total variance in severity of psychopathology over time, while all three personality domains along with both partnership rupture and job loss explained 59% of total variance. In conclusion, personality, especially neuroticism, relates consistently to repeated measures of psychopathology. These associations are independent of and more pervasive than the effects of partnership rupture and job loss. Partnership rupture in interaction with neuroticism may further increase the risk for SUD. We conclude that neuroticism is a fundamental aetiological factor for severe psychopathology, but further testing of this model in other longitudinal studies is required.

Bisexuality among a cohort of university students: prevalence and psychological distress

Sociocultural prejudices and pressures may impair the mental health of bisexual people. We aim to evaluate psychological status according to sexual orientation in a sample of Italian university students, with specific attention to bisexuality and its frequency. Among a recruited sample of 551 university students, we found the following percentages for sexual orientation: heterosexuals 96.9% (n = 534), homosexuals 1.1% (n = 6), bisexuals 2% (n = 11). The cross-sectional analysis for psychological symptoms, with the Symptoms Check List-90 Revised (SCL-90-R), revealed that bisexual subjects have statistically significant higher scores on some symptomatic scales compared to heterosexuals. In particular, obsession-compulsion, paranoid ideation, hostility were significantly higher in bisexuals. Therefore, if heterosexual or homosexual orientation are not specified by particular psychological symptoms, bisexuality is characterized by a strong link with some facets of psychological distress, which are likely caused by a peculiar double stigma. In conclusion, through a specific psychometric tool, we found an association between bisexuality and various forms of psychological suffering. This evidence should further encourage clinicians to accurately assess the psychological health in young bisexual people.

Course of psychotic symptoms, depression and global functioning in persons at clinical high risk of psychosis: Results of a longitudinal observation study over three years focusing on both converters and non-converters

The aim of this study was to test the validity of the CHR state by focusing on the course of psychosis spectrum symptoms, depression and global functioning in converters and non-converters. A total of 188 CHR-positive subjects (60.2% men) aged between 13 and 35years (mean=20.5) at study outset were assessed five times (t0-t4) over a total observation period of 36months. Conversion to manifest psychosis was defined according to ICD-10 criteria for schizophrenia (F20) or brief psychotic disorder (F23). Measures of positive and negative symptoms were assessed with the Structured Interview for Prodromal Syndromes (SIPS), depression with the Calgary Depression Scale (CDS), and global functioning with the Global Assessment of Functioning Scale (GAF). Converters scored higher over time on all SIPS scales apart from grandiosity (Cohen's d: 0.5-0.7; all p<0.001), higher on the CDS (d=0.43, p=0.001) and lower on the GAF (d=0.69, p<0.001) than did non-converters. Positive and negative symptoms as well as depression were most severe at study outset (t0) and then declined sharply following a linear function over the three-year observation period (t1-t4) across groups (all linear contrasts p<0.001). In conclusion, converters showed significantly more psychopathological symptoms and poorer functioning before crossing the diagnostic threshold for manifest psychosis. CHR-subjects who convert to manifest psychosis during follow-up appear to be recovering from illness rather than becoming ill. Major issues involve the poor discrimination of CHR state and psychosis as well as the dichotomous definition of both at-risk and disease states. Further examination in other CHR-samples is warranted.

Big Five Personality Traits and the General Factor of Personality as Moderators of Stress and Coping Reactions Following an Emergency Alarm on a Swiss University Campus

We conducted an online survey including 306 participants aged 18-64 years to assess the general factor of personality (GFP) and Big Five personality traits in relation to individual stress and coping reactions following a shooting emergency alarm at a Swiss university campus. Although the emergency eventually turned out to be a false alarm, various witnesses showed pronounced distress owing to a vast police operation. The GFP structure was replicated using two alternative modelling approaches. Neuroticism related substantially to acute fear and traumatic distress as well as to more enduring maladaptive coping. Agreeableness was negatively associated with the coping strategy of medication use, whereas both agreeableness and conscientiousness related positively to social activity following the emergency. The GFP related moderately to peri-traumatic distress and showed a substantial negative association with medication use and a strong positive association with social activity. In conclusion, both the GFP and Big Five traits significantly moderate stress responses following a stressful life event. The GFP predominantly relates to socially adaptive coping, whereas in particular neuroticism accounts for acute stress reactions such as fear and traumatic distress. These findings support the notion that personality influences how persons react in the face of adversity. Copyright © 2016 John Wiley & Sons, Ltd.

Neurological soft signs: Effects of trait schizotypy, psychological distress and auditory hallucination predisposition

Schizotypy is regarded as a trait vulnerability for psychotic disorders, yet alone is insufficient for development of a diagnosable disorder. Additional symptoms and psychological distress are necessary for help seeking and transition from an at risk mental state to a clinical diagnosis. The present study investigated the interaction between trait schizotypy, state auditory verbal hallucination (AVH) predisposition, distress and handedness for the expression of neurological soft signs (NSS), a neurodevelopmental vulnerability factor for psychosis. Cluster analysis formed schizotypy groups statistically across the dimensions captured by the SPQ. It was hypothesized that schizotypy and AVH predisposition would interact, resulting in significantly greater NSS. Psychological distress and handedness were hypothesized to be significant covariates, accounting for some variance in the expression of NSS between the groups. A sample of University students (n = 327) completed the Schizotypal Personality Questionnaire, Launay-Slade Hallucination Scale, General Health Questionnaire and the Neurological Evaluation Scale (NES). Cluster Analysis revealed four schizotypy groups. Distress was not a significant covariate in any analysis. As expected, those with high overall schizotypy and high AVH predisposition expressed significantly greater Motor-Coordination NSS compared to those with high schizotypy and low AVH predisposition. Within the Mixed Interpersonal and Cognitive-Perceptual Schizotypy cluster, those with low AVH predisposition expressed significantly more Motor-Coordination NSS than those with high AVH predisposition. These findings suggest motor coordination NSS are detectable in schizotypy, and AVH predisposition appears to interact with these traits. This study highlights the importance of considering both trait and subclinical state risk factors when investigating risk for psychosis.

Big Five personality traits may inform public health policy and preventive medicine: Evidence from a cross-sectional and a prospective longitudinal epidemiologic study in a Swiss community

BACKGROUND

Some evidence documents the importance of personality assessments for health research and practise. However, no study has opted to test whether a short self-report personality inventory may comprehensively inform health policy.

METHODS

Data were taken from a population-based epidemiologic survey in Zurich, Switzerland, conducted from 2010-2012. A short form of the Big Five Inventory was completed by n=1155 participants (54.4% women; mean age=29.6 years), while health-related outcomes were taken from a comprehensive semi-structured clinical interview. A convenience subsample averaging n=171 participants additionally provided laboratory measures and n=133 were subsequently followed-up at least once over a maximal period of 6 months.

RESULTS

Personality traits, in particular high neuroticism and low conscientiousness, related significantly to poor environmental resources such as low social support (R(2)=0.071), health-impairing behaviours such as cannabis use (R(2)=0.071), and psychopathology, including negative affect (R(2)=0.269) and various mental disorders (R(2)=0.060-0.195). The proportion of total variance explained was R(2)=0.339 in persons with three or more mental disorders. Personality significantly related to some laboratory measures including total cholesterol (R(2)=0.095) and C-Reactive Protein (R(2)=0.062). Finally, personality prospectively predicted global psychopathological distress and vegetative symptoms over a 6-month observation period.

CONCLUSIONS

Personality relates consistently to poor socio-environmental resources, health-impairing behaviours and psychopathology. We also found some evidence for an association with metabolic and immune functions that are assumed to influence health. A short personality inventory could provide valuable information for preventive medicine when used as a means to screen entire populations for distinct risk exposure, in particular with respect to psychopathology.

Schizotypal traits in adolescents with 22q11.2 deletion syndrome: validity, reliability and risk for psychosis

BACKGROUND

Very little is known about the phenotypic expression of schizotypal traits in individuals with 22q11.2 deletion syndrome (22q11DS). The main purpose was to analyse the factorial structure, internal consistency and temporal stability of schizotypal traits, as well as their associations with prodromal states and clinical psychotic symptoms in adolescents with 22q11DS.

METHOD

The sample comprised 61 adolescents with 22q11DS (mean = 14.95 years, s.d. = 2.13; n = 24 at follow-up). An age-matched comparison group (n = 61, mean = 15.44 years, s.d. = 1.76) was also included. The Schizotypal Personality Questionnaire (SPQ), the Structured Interview for Prodromal Syndromes, the Positive and Negative Syndrome Scale, and the Brief Psychiatric Rating Scale were used.

RESULTS

Adolescents with 22q11DS scored higher than the control group on the interpersonal dimension and suspiciousness subscale of the SPQ. The analysis of the internal structure of the SPQ in the sample of 22q11DS participants yielded a three-component solution (cognitive-perceptual, interpersonal, and disorganized). In addition, internal consistency coefficients ranged between 0.63 and 0.91. The schizotypal traits were highly stable across a 3.6-year interval, and ranged from 0.50 to 0.63. Self-reported schizotypal traits correlated with interview-based ratings of prodromal states and psychotic symptoms.

CONCLUSIONS

These results indicate that the SPQ may be a valid tool to assess schizotypal traits in adolescents with 22q11DS. The identification of a reliable self-report instrument for use in individuals with learning disabilities and at genetic high risk for psychosis could be useful in clinical and research settings. Assessment of schizotypal traits may be used as a distal risk marker and in a close-in strategy in high-risk genetic samples to enhance the possibility of early detection of psychosis.

You Don't See What I See: Individual Differences in the Perception of Meaning from Visual Stimuli

Everyone has their own unique version of the visual world and there has been growing interest in understanding the way that personality shapes one's perception. Here, we investigated meaningful visual experiences in relation to the personality dimension of schizotypy. In a novel approach to this issue, a non-clinical sample of subjects (total n = 197) were presented with calibrated images of scenes, cartoons and faces of varying visibility embedded in noise; the spatial properties of the images were constructed to mimic the natural statistics of the environment. In two experiments, subjects were required to indicate what they saw in a large number of unique images, both with and without actual meaningful structure. The first experiment employed an open-ended response paradigm and used a variety of different images in noise; the second experiment only presented a series of faces embedded in noise, and required a forced-choice response from the subjects. The results in all conditions indicated that a high positive schizotypy score was associated with an increased tendency to perceive complex meaning in images comprised purely of random visual noise. Individuals high in positive schizotypy seemed to be employing a looser criterion (response bias) to determine what constituted a 'meaningful' image, while also being significantly less sensitive at the task than those low in positive schizotypy. Our results suggest that differences in perceptual performance for individuals high in positive schizotypy are not related to increased suggestibility or susceptibility to instruction, as had previously been suggested. Instead, the observed reductions in sensitivity along with increased response bias toward seeing something that is not there, indirectly implicated subtle neurophysiological differences associated with the personality dimension of schizotypy, that are theoretically pertinent to the continuum of schizophrenia and hallucination-proneness.

Association between processing speed and subclinical psychotic symptoms in the general population: focusing on sex differences

Evidence is growing that persons along the schizophrenia spectrum, i.e., those who also display subclinical psychotic symptoms, exhibit deficits across a broad range of neuropsychological domains. Because sex differences in the association between cognitive deficits and psychosis have thus far been mostly neglected, we believe that ours is the first study specifically focused upon those differences when examining the relationship between subclinical psychosis and processing speed. Using a sample of 213 persons from the general population from Zurich, Switzerland, psychotic symptoms were assessed with three different questionnaires including the Schizotypal Personality Questionnaire, an adaptation of the Structured Interview for Assessing Perceptual Anomalies, and the Paranoia Checklist. Processing speed was assessed with the WAIS digit-symbol coding test. Two higher-order psychosis domains were factor-analytically derived from the various psychosis subscales and then subjected to a series of linear regression analyses. The results demonstrate that in both men and women associations between subclinical psychosis domains and processing speed were weak to moderate (β ranging from -0.18 to -0.27; all p<0.05). However, we found no sex-differences in the interrelation of subclinical psychosis and processing speed (ΔR(2)<0.005; p>0.30). In conclusion, it appears that sex differences in psychosis manifest themselves only at the high end of the continuum (full-blown schizophrenia) and not across the sub-threshold range. The small magnitude of the effects reported herein conforms to the etiopathology of the disorder. Since schizophrenia and related disorders from the spectrum are assumed to be multifactorial diseases, it follows that many etiological components of small effect are involved.

Schizotypy from a developmental perspective

The schizotypy construct focuses attention on the liability to develop schizophrenia-spectrum disorders, yet traditionally, the schizotypy models have put more emphasis on stress-vulnerability interactions rather than developmental dynamics of emerging risk for psychopathology. Indeed, developmental accounts of this emerging personality trait have rarely been explicitly formulated. In this position article, we wish to convey some of the basic developmental tenets of schizotypy, and how they can inform high-risk research. Firstly, we tackle the state vs trait issue to outline the possible relationship between high-risk states and trait schizotypy. Second, we review the evidence suggesting that the consolidation of schizotypy, encompassing its 3 main dimensions, could be considered as a developmental mediator between very early risk factors and transition into high-risk states. Importantly, developmental dynamics between endophenotypes, as well as transactional and epigenetics mechanisms should enter modern conceptualizations of schizotypy. Finally, we present a developmental psychopathology perspective of schizotypy sensitive to both the multifinality and equifinality of schizophrenia-spectrum disorders. We conclude that schizotypy represents a crucial construct in a fully-developmental study of schizophrenia-spectrum disorders.

Assessing sub-clinical psychosis phenotypes in the general population--a multidimensional approach

Several studies have demonstrated that expression of a psychosis phenotype can be observed below the threshold of its clinical detection. To date, however, no conceptual certainty has been reported for the validity and reliability of sub-clinical psychosis. Our main objectives were to assess the prevalence rates and severity of various psychosis symptoms in a representative community sample. Furthermore, we wanted to analyze which latent factors are depicted by several currently used psychosis questionnaires. We also examined how those latent factors for sub-clinical psychosis are linked to psychosocial factors, normal personality traits, and coping abilities related to chronic stress. Most of the eight subscales from the Paranoia Checklist and the Structured Interview for Assessing Perceptual Anomalies had a very similar type of distribution, i.e., an inverse Gaussian (Wald) distribution. This supported the notion of a continuity of psychotic symptoms, which we would expect to find for continuously distributed symptoms within the general population. Sub-clinical psychosis can be reduced to two different factors - one representing odd beliefs about the world and odd behavior, and the other one representing anomalous perceptions (such as hallucinations). Persons with odd beliefs and behavior are under greater burden and more susceptible to psychosocial risks than are persons with anomalous perceptions. These sub-clinical psychosis syndromes are also related to stable personality traits. In conclusion, we obtained strong support for the notion that there is no natural cut-off separating psychotic illness from good health. Sub-clinical psychosis of any kind is not trivial because it is associated with various types of social disability.

The Detrimental Impact of Maladaptive Personality on Public Mental Health: A Challenge for Psychiatric Practice

Experts in personality psychology and personality disorders have long emphasized the pervasive and persistent detrimental impact of maladaptive personality traits on mental health and functioning. However, in routine psychiatric practice, maladaptive personality is readily ignored and personality traits are seldom incorporated into clinical guidelines. The aim of this narrative review is to outline how pervasively personality influences public mental health and how personality thereby challenges common psychiatric practice. A comprehensive search and synthesis of the scientific literature demonstrates that maladaptive personality traits and personality disorders, in particular high neuroticism and negative affectivity, first, are risk factors for divorce, unemployment, and disability pensioning; second, relate to the prevalence, incidence, and co-occurrence of common mental disorders; third, impair functioning, symptom remission, and recovery in co-occurring common mental disorders; and fourth, predispose to treatment resistance, non-response and poor treatment outcome. In conclusion, maladaptive personality is not only involved in the development and course of mental disorders but also predisposes to chronicity and re-occurrence of psychopathology and reduces the efficacy of psychiatric treatments. The pernicious impact of maladaptive personality on mental health and functioning demands that careful assessment and thorough consideration of personality should be compulsory in psychiatric practice.