Subclinical psychosis syndromes in the general population: results from a large-scale epidemiological survey among residents of the canton of Zurich, Switzerland

Ecological momentary assessment (EMA) combined with unsupervised machine learning shows sensitivity to identify individuals in potential need for psychiatric assessment

Ecological momentary assessment (EMA), a structured diary assessment technique, has shown feasibility to capture psychotic(-like) symptoms across different study groups. We investigated whether EMA combined with unsupervised machine learning can distinguish groups on the continuum of genetic risk toward psychotic illness and identify individuals with need for extended healthcare. Individuals with psychotic disorder (PD, N = 55), healthy individuals (HC, N = 25) and HC with first-degree relatives with psychosis (RE, N = 20) were assessed at two sites over 7 days using EMA. Cluster analysis determined subgroups based on similarities in longitudinal trajectories of psychotic symptom ratings in EMA, agnostic of study group assignment. Psychotic symptom ratings were calculated as average of items related to hallucinations and paranoid ideas. Prior to EMA we assessed symptoms using the Positive and Negative Syndrome Scale (PANSS) and the Community Assessment of Psychic Experience (CAPE) to characterize the EMA subgroups. We identified two clusters with distinct longitudinal EMA characteristics. Cluster 1 (NPD = 12, NRE = 1, NHC = 2) showed higher mean EMA symptom ratings as compared to cluster 2 (NPD = 43, NRE = 19, NHC = 23) (p < 0.001). Cluster 1 showed a higher burden on negative (p < 0.05) and positive (p < 0.05) psychotic symptoms in cross-sectional PANSS and CAPE ratings than cluster 2. Findings indicate a separation of PD with high symptom burden (cluster 1) from PD with healthy-like rating patterns grouping together with HC and RE (cluster 2). Individuals in cluster 1 might particularly profit from exchange with a clinician underlining the idea of EMA as clinical monitoring tool.

Mismatch negativity generation in subjects at risk for psychosis: source analysis is more sensitive than surface electrodes in risk prediction

Background

Deficits of mismatch negativity (MMN) in patients with schizophrenia have been demonstrated many times and there is growing evidence that alterations of MMN already exist in individuals at risk for psychosis. The present study examines differences in MMN between subjects fulfilling ultra-high risk (UHR) or only basic symptoms criteria and it addresses the question, if MMN source analysis can improve prediction of transition to psychosis.

Methods

The MMN to duration, frequency, and intensity deviants was recorded in 50 healthy controls and 161 individuals at risk for psychosis classified into three subgroups: only basic symptoms (n = 74), only ultra-high risk (n = 13) and persons who fulfill both risk criteria (n = 74). Based on a three-source model of MMN generation, we conducted an MMN source analysis and compared the amplitudes of surface electrodes and sources among the three groups.

Results

Significant differences in MMN generation among the four groups were revealed at surface electrodes Cz and C4 (p < 0.05) and at the frontal source (p < 0.001) for duration deviant stimuli. The 15 subjects from the risk groups who subsequently developed a manifest psychosis had a significantly lower MMN amplitude at frontal source (p = 0.019) without showing significant differences at surface electrodes. Low activity at frontal MMN source increased the risk of transition to manifest disease by the factor 3.12 in UHR subjects.

Conclusion

MMN activity differed significantly between subjects presenting only basic symptoms and subjects which additionally meet UHR criteria. The largest differences between groups as well as between individuals with and without transition were observed at the frontal source. The present results suggest that source analysis is more sensitive than surface electrodes in psychosis risk prediction by MMN.

Genome-wide identification of the shared genetic basis of cannabis and cigarette smoking and schizophrenia implicates NCAM1 and neuronal abnormality

OBJECTIVES

Confirming the existence and composition of the shared genetic basis of Schizophrenia and cannabis and cigarette smoking has critical values for the clinical prevention and intervention of psychosis.

METHODS

To achieve this goal, we leveraged Genome-Wide summary statistics of Schizophrenia (n = 99,934), cigarette smoking (n = 518,633) and cannabis usage (n = 162,082). We applied Causal Analysis Using Summary Effect Estimates (CAUSE) and genomic structural equation modeling (GenomicSEM) to quantify the contribution of a common genetic factor of cannabis and cigarette smoking and schizophrenia (referred to as SCZ_SMO), then identified genome-wide loci that made up SCZ_SMO.

RESULTS

We estimated that SCZ_SMO explained 8.6% of Schizophrenia heritability (Z score <-2.5 in CAUSE, p<10^-20 in Genomic SEM). There were 20 independent loci showing association with SCZ_SMO at the genome-wide threshold of p<5 × 10^-8. At the top locus on chromosome 11, fine-mapping identified rs7945073 (posterior inclusion probability =0.12, p = 2.24 × 10^-32) as the top risk variants. Gene-level association and fine-mapping highlighted NCAM1, PHC2, and SEMA6D as risk genes of SCZ_SMO. Other risk genes were enriched in cortex, neuron, and dendritic spines (adjusted p<0.05). SCZ_SMO showed significant positive correlation (p<10^-6) with the genetic risk of attention deficit hyperactivity disorder (r = 0.50), lifestyle problems (r = 0.83), social deprivation (r = 0.58) and all-cause pregnant loss (r = 0.60).

CONCLUSION

Our result provided new evidence on the shared genetic basis model for the association between Schizophrenia and smoking and provided genetic and biological insights into their shared mechanism.

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.

Genetic overlap and causal associations between smoking behaviours and mental health

Cigarette smoking is a modifiable behaviour associated with mental health. We investigated the degree of genetic overlap between smoking behaviours and psychiatric traits and disorders, and whether genetic associations exist beyond genetic influences shared with confounding variables (cannabis and alcohol use, risk-taking and insomnia). Second, we investigated the presence of causal associations between smoking initiation and psychiatric traits and disorders. We found significant genetic correlations between smoking and psychiatric disorders and adult psychotic experiences. When genetic influences on known covariates were controlled for, genetic associations between most smoking behaviours and schizophrenia and depression endured (but not with bipolar disorder or most psychotic experiences). Mendelian randomization results supported a causal role of smoking initiation on psychiatric disorders and adolescent cognitive and negative psychotic experiences, although not consistently across all sensitivity analyses. In conclusion, smoking and psychiatric disorders share genetic influences that cannot be attributed to covariates such as risk-taking, insomnia or other substance use. As such, there may be some common genetic pathways underlying smoking and psychiatric disorders. In addition, smoking may play a causal role in vulnerability for mental illness.

Rural birth/upbringing and childhood adversities are associated with psychotic experiences in university students in China

BACKGROUND

Urbanicity has been reported to associate with an increased risk of psychotic experiences (PEs) in developed countries but less is known about the situation in developing countries. The present study aimed to investigate the effects of birth/upbringing place and other environmental factors on PEs in Chinese university students.

METHODS

A computer-assisted cross-sectional survey was conducted on 4620 second-year undergraduates, using a stratified cluster sampling. Birth places and residential mobility before 16 years old were recorded. PEs were measured using the subscales of psychoticism and paranoid ideation in the Symptom Checklist-90-R (SCL-90-R). Six questions extracted from the childhood section of the World Mental Health Composite International Diagnostic Interview (WMH-CIDI) were used to assess childhood trauma.

RESULTS

Generalized ordered logit model of multiple regression analysis revealed that participants with rural birth/upbringing (e.g. rural upbringing, on graded factor score of psychoticism and paranoid ideation [GFSPPI], 0 versus 1 & 2, odds ratio [OR] 1.409, 95% CI 1.219-1.628, p < 0.00001; 0 & 1 versus 2, OR 1.584, 95% CI 1.179-2.128, p < 0.00001) and those who reported childhood trauma (e.g. on GFSPPI, 0 versus 1 & 2, OR 1.737, 95% CI 1.498-2.014, p < 0.00001; 0 & 1 versus 2, OR 1.618, 95% CI 1.224-2.140, p < 0.00001) were apt to present more severe PEs. While upbringing places and childhood trauma affected both the presence and the severity of PEs, gender affected the presence or absence of PEs only (e.g. females, on GFSPPI, 0 versus 1 & 2, OR 1.887, 95% CI 1.631-2.183, p < 0.00001; 0 & 1 versus 2, OR 0.927, 95% CI 0.702-1.223, p = 0.593). Besides, the number of risk factors was associated with the severity of PEs in the cumulative odds logistic regression analysis (e.g. 3 risk factors versus 0 risk factor, on GFSPPI, OR 4.126, 95% CI 3.075-5.537, p < 0.00001).

CONCLUSIONS

Female, rural birth/upbringing and childhood trauma are risk factors of PEs in university students in China. The discrepancy in the findings between developed countries and China has important implications for urbanicity as a risk factor for PEs.

A Twin Study on the Association Between Psychotic Experiences and Tobacco Use During Adolescence

OBJECTIVE

Psychotic experiences (PE) are dimensional phenomena in the general population that resemble psychotic symptoms, such as paranoia and hallucinations. This is the first twin study to explore the degree to which tobacco use and PE share genetic or environmental influences. Previous studies on the association between adolescent tobacco use and PE have not considered PE dimensionally, included negative symptoms, or accounted for confounding by sleep disturbance and stressful life events.

METHOD

An unselected adolescent twin sample (N = 3,787 pairs; mean age = 16.16 years) reported on PE (paranoia, hallucinations, cognitive disorganization, grandiosity, and anhedonia) and regularity of tobacco use. Parents rated the twins' negative symptoms. Regression analyses were conducted while adjusted for sociodemographic characteristics, prenatal maternal smoking, cannabis use, sleep disturbance, and stressful life events. Bivariate twin modeling was used to estimate the degree of genetic and common and unique environmental influences shared between tobacco use and PE.

RESULTS

Regular smokers were significantly more likely to experience paranoia, hallucinations, cognitive disorganization, and negative symptoms (β = 0.17-0.34), but not grandiosity or anhedonia, than nonsmokers, after adjustment for confounders. Paranoia, hallucinations, and cognitive disorganization correlated ≥0.15 with tobacco use (r = 0.15-0.21, all p < .001). Significant genetic correlations (r_A=0.37-0.45) were found. Genetic influences accounted for most of the association between tobacco use and paranoia (84%) and cognitive disorganization (81%). Familial influences accounted for 80% of the association between tobacco use and hallucinations.

CONCLUSION

Tobacco use and PE during adolescence were associated after adjustment for confounders. They appear to co-occur largely because of shared genetic influences.

The prevalence of childhood trauma in psychiatric outpatients

BACKGROUND

The aim of this present study was to compare the prevalence and type of trauma experienced by community sample with the outpatient sample with mental disorders.

METHODS

A total of 354 outpatients, aged 14-35 years old, with mood disorders, schizophrenia and other psychotic disorders, adjustment disorder and anxiety disorder were recruited from a tertiary psychiatric hospital. A total of 100 healthy controls were recruited from the Singapore general population by snowballing. The Childhood Trauma Questionnaire-Short Form (CTQ-SF) designed to measure childhood trauma and the severity (e.g., physical abuse, emotional abuse, sexual abuse, physical neglect and emotional neglect) was administered to participants. Socio-demographic and clinical characteristics were obtained from interviews with the participants and from outpatients' medical records, respectively. Independent sample t tests and Chi-square tests were used to investigate the differences between the outpatient and community samples.

RESULTS

Overall the CTQ-SF total and domain scores indicated that outpatient sample experienced higher rate of traumatic life events in childhood than community sample. Two most reported trauma types were emotional abuse (n = 81, 59.1%) and physical neglect (n = 74, 54%) reported by the mood disorder group. In the community sample, emotional neglect (n = 46, 46%) and physical neglect (n = 18, 18%) were the most commonly reported trauma type. Overall outpatient sample (n = 80, 22.6%) and community sample (n = 28, 28%) reported at least one type of trauma.

CONCLUSION

The findings indicate higher rates of CTQ-SF total and domain scores in outpatient sample demonstrating a higher rate of traumatic life events in childhood compared to community sample. Further research in childhood trauma is needed to improve the knowledge in psychiatric clinic practices.

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.

Health and quality of life in patients with medication overuse headache syndrome after standardized inpatient rehabilitation: A cross-sectional pilot study

The aim of this pilot study was to determine health-related quality of life (HRQoL) in patients with history of medication overuse headache (MOH) after detoxification and a headache-specific inpatient rehabilitation program and to receive necessary information for future prospective studies.HRQoL and headache-related disability were cross-sectionally measured by Short Form 36 (SF-36), Hospital Anxiety and Depression Scale (HADS), Migraine Disability Score (MIDAS), Coping Strategies Questionnaire (CSQ), and Symptom Checklist 90 revised (SCL-90-R). SF-36, HADS, and SCL-90-R data were compared to German population norms, stratified by age, sex, and comorbidities.Fifty-one patients (72.5% females, mean age 47.3 years) were included with an average headache duration of 25.3 years. Moderate to high levels of headache were reported on the MIDAS VAS at 6.51 (range 0-10); SF-36 bodily pain was 40.3 (norm = 59.0, P < .001, 100 = best). Impaired functioning averaged at 78.4 (100 = no impairment) on the MIDAS. In contrast, SF-36 physical functioning was comparable to the norm (mean: 78.4, norm = 81.8, P = .63). All other SF-36 scales were significantly lower than expected from the norm (all P < .001). The scales depression, anxiety, obsessive-compulsive, and interpersonal sensitivity were significantly affected, whereas the levels of SCL-90-R schizophrenia nuclear and schizotypia were not lower than the norm. Coping with pain was moderate.This pilot study is the first that presents a comprehensive and simultaneously specific assessment of health and quality of life of MOH patients after detoxification and inpatient rehabilitation. Moderate to high levels of pain and self-reported disability owing to headache were observed, whereas physical function on the SF-36 was not different from the expected level of the norm. Mental health was substantially affected in several dimensions, which had been described to reduce the ability to cope with pain. MOH patients seem to have high expectations of functionality, low symptomatology, and intact well-being.

Poverty, low education, and the expression of psychotic-like experiences in the general population of São Paulo, Brazil

The aim of our study was to assess psychotic-like experiences in the general population aged 18-30 years old of the city of São Paulo, Brazil. A household survey was conducted with 1950 young-adults randomly drawn from the city's general population. The validated 92-item Portuguese version of the Prodromal Questionnaire (PQ) was used for face-to-face interviews. Latent class analysis was conducted. Mean age was of 24 years; 51.1% of the sample was of women. Mean total score on the PQ was 22.06 (SD=17.16). Considering a suggested cut-off of 14 in the positive subscale, 30.8% of individuals were above the threshold for ultra-high risk for psychosis detection. Latent class analysis resulted in a three classes clusterization. Class 1 (20%; n=390) had the highest overall PQ scores (mean=49.31,SD=10.783), class 2 (43%; n=835) had intermediate scores (mean=23.37,SD=6.56), and class 3 (37%; n=721) had the lowest scores (mean=5.81,SD=3.74). Class 1 had significantly more individuals with less education and significantly more individuals with lower socioeconomic class. Poverty and low education might be associated with the psychotic expression in the general population, amplifying their actions on the psychosis gradient in developing countries. The psychosis continuum might be constituted by three distinct quantitatively different classes.

Psychotic-Like Experiences at the Healthy End of the Psychosis Continuum

There is increasing evidence pointing toward a continuous distribution of psychotic symptoms and accompanying factors between subclinical and clinical populations. However, for the construction of continuum models, a more detailed knowledge of different types of psychotic-like experiences (PLE) and their associations with distress, functional impairment, and demographic variables is needed. We investigated PLE in a sample of healthy adults (N = 206) incorporating the recently developed revised Exceptional Experiences Questionnaire (PAGE-R). For the first time, the PAGE-R was cross validated with PLE, disorganized-, and negative-like symptoms [Schizotypal Personality Questionnaire (SPQ), Physical Anhedonia Scale (PAS)]. We subjected the PAGE-R to exploratory factor analyses and examined the resulting subtypes of EE for specific associations with contextual factors, valence ratings, socio-demographic variables, and general psychological burden (Revised Symptom-Checklist-90). Correlational cross-validation suggested that the PAGE-R measures facets of PLE. Importantly, we (1) identified three types of exceptional experiences (EE): Odd beliefs, dissociative anomalous perceptions, and hallucinatory anomalous perceptions. Further, the results suggested that even in healthy individuals (2) PLE and EE are indicative of reduced functioning, as reflected by increased psychological burden and lower educational achievement. Moreover, (3) similar sex-differences might exist as in psychotic patients with women reporting more positive-like symptoms and EE but less disorganized-like symptoms than men. Importantly, (4) EE might be differentially implicated in psychological functioning. We suggest that the PAGE-R holds the potential to complement the current assessment of sub-clinical psychosis. However, whereas our results might point toward a continuity of psychotic symptoms with EE and normal experiences, they require replication in larger samples as well as equivalence testing across the psychosis continuum. Future analyses incorporating the PAGE-R might shed more light onto mechanisms that are implicated in the progress or resilience toward clinical illness.

Embrained drives to perform extraordinary roles predict schizotypal traits in the general population

Some personal drives correspond to extraordinary social roles. Given that behavioral strategies associated with such drives may conflict with those associated with ordinary roles, they could cause behavioral disorganization. To test whether they do so independent of the factors responsible for full-blown schizotypy and schizophrenia, these drives were assessed in the general population. Two hundred and nine healthy volunteers were individually presented with hundreds of names of social roles in experimental psychology conditions. The task of the participant was to decide whether or not (s)he would consider performing the role at any moment of his/her life. Schizotypal traits were measured with the schizotypal personality questionnaire (SPQ), and delusion-like ideations were assessed by the Peters et al. Delusion Inventory. Demographics and social desirability were controlled for. Participants accepting a greater percentage of extraordinary roles had higher SPQ scores. Among the three factors of the SPQ, disorganization was the one best predicted by those percentages. This correlation (r=0.40, P=7.2E−09) was significantly greater (Fisher Z-transform, P=0.003) than the correlation between the percentages of ordinary roles accepted and the SPQ scores (r=0.145, P=0.044). Reaction times revealed no suboptimal cognitive functioning in high accepters of extraordinary roles and further strengthened the drive hypothesis. Their acceptances of roles were done faster and their rejections took longer than those of low accepters (P=5E−12). Culturally embrained drives to do extraordinary roles could thus be an independent factor of the symptoms measured in the normality to schizophrenia continuum.

Lay Judgments of Mental Health Treatment Options: The Mind Versus Body Problem

Background: Past research shows that people believe psychologically caused mental disorders are helped by different treatments than biologically caused mental disorders. However, it is unknown how people think about treatment when limited information is known to identify the disorder. Objective: Our objective was to explore how laypeople judged the helpfulness of treatments when a limited set of mental health symptoms is presented. Method: Across four experiments, Mechanical Turk and college undergraduate participants (N = 331) read descriptions displaying sets of three mental health symptoms and rated how helpful pharmaceuticals, counseling, or alternative medicine would be on a 0 (not at all helpful) to 100 (completely helpful) scale. We measured judgments for perceived mental and medical symptoms (Experiment 1) and how judgments were influenced by symptom severity (Experiment 2), duration (Experiment 3), and if alternative medicine and conventional treatments were used in conjunction (Experiment 4). Results: Perceived mental symptoms were rated as helped by counseling, while perceived medical symptoms were rated as helped by medication. Alternative medicine was never rated as extremely helpful. For example, in Experiment 1, counseling (mean [M] = 80.1) was rated more helpful than pharmaceuticals (M = 50.5; P < 0.001) or alternative medicine (M = 45.1; P < 0.001) for mental symptoms, and pharmaceuticals (M = 62.6) was rated more helpful than counseling (M = 36.1; P < 0.001) or alternative medicine (M = 47.5; P < 0.001) for medical symptoms. This pattern held regardless of severity, duration, or the adjunct use of alternative medicine. Limitations: We employed a general population sample and measured hypothetical treatment judgments. Conclusions: Mental health symptoms viewed as problems of the mind are thought to need different treatment than mental health symptoms seen as problems of the body.

Distribution of Response Time, Cortical, and Cardiac Correlates during Emotional Interference in Persons with Subclinical Psychotic Symptoms

A psychosis phenotype can be observed below the threshold of clinical detection. The study aimed to investigate whether subclinical psychotic symptoms are associated with deficits in controlling emotional interference, and whether cortical brain and cardiac correlates of these deficits can be detected using functional near-infrared spectroscopy (fNIRS). A data set derived from a community sample was obtained from the Zurich Program for Sustainable Development of Mental Health Services. 174 subjects (mean age 29.67 ± 6.41, 91 females) were assigned to four groups ranging from low to high levels of subclinical psychotic symptoms (derived from the Symptom Checklist-90-R). Emotional interference was assessed using the emotional Stroop task comprising neutral, positive, and negative conditions. Statistical distributional methods based on delta plots [behavioral response time (RT) data] and quantile analysis (fNIRS data) were applied to evaluate the emotional interference effects. Results showed that both interference effects and disorder-specific (i.e., group-specific) effects could be detected, based on behavioral RTs, cortical hemodynamic signals (brain correlates), and heart rate variability (cardiac correlates). Subjects with high compared to low subclinical psychotic symptoms revealed significantly reduced amplitudes in dorsolateral prefrontal cortices (interference effect, p < 0.001) and middle temporal gyrus (disorder-specific group effect, p < 0.001), supported by behavioral and heart rate results. The present findings indicate that distributional analyses methods can support the detection of emotional interference effects in the emotional Stroop. The results suggested that subjects with high subclinical psychosis exhibit enhanced emotional interference effects. Based on these observations, subclinical psychosis may therefore prove to represent a valid extension of the clinical psychosis phenotype.

Shall we really say goodbye to first rank symptoms?

BACKGROUND

First rank symptoms (FRS) of schizophrenia have been used for decades for diagnostic purposes. In the new version of the DSM-5, the American Psychiatric Association (APA) has abolished any further reference to FRS of schizophrenia and treats them like any other "criterion A" symptom (e.g. any kind of hallucination or delusion) with regard to their diagnostic implication. The ICD-10 is currently under revision and may follow suit. In this review, we discuss central points of criticism that are directed against the continuous use of first rank symptoms (FRS) to diagnose schizophrenia.

METHODS

We describe the specific circumstances in which Schneider articulated his approach to schizophrenia diagnosis and discuss the relevance of his approach today. Further, we discuss anthropological and phenomenological aspects of FRS and highlight the importance of self-disorder (as part of FRS) for the diagnosis of schizophrenia. Finally, we will conclude by suggesting that the theory and rationale behind the definition of FRS is still important for psychopathological as well as neurobiological approaches today.

RESULTS

Results of a pivotal meta-analysis and other studies show relatively poor sensitivity, yet relatively high specificity for FRS as diagnostic marker for schizophrenia. Several methodological issues impede a systematic assessment of the usefulness of FRS in the diagnosis of schizophrenia. However, there is good evidence that FRS may still be useful to differentiate schizophrenia from somatic causes of psychotic states. This may be particularly important in countries or situations with little access to other diagnostic tests. FRS may thus still represent a useful aid for clinicians in the diagnostic process.

CONCLUSION

In conclusion, we suggest to continue a tradition of careful clinical observation and fine-grained psychopathological assessment, including a focus on symptoms regarding self-disorders, which reflects a key aspect of psychosis. We suggest that the importance of FRS may indeed be scaled down to a degree that the occurrence of a single FRS alone should not suffice to diagnose schizophrenia, but, on the other hand, absence of FRS should be regarded as a warning sign that the diagnosis of schizophrenia or schizoaffective disorder is not warranted and requires specific care to rule out other causes, particularly neurological and other somatic disorders. With respect to the current stage of the development of ICD-11, we appreciate the fact that self-disorders are explicitly mentioned (and distinguished from delusions) in the list of mandatory symptoms but still feel that delusional perceptions and complex hallucinations as defined by Schneider should be distinguished from delusions or hallucinations of "any kind". Finally, we encourage future research to explore the psychopathological context and the neurobiological correlates of self-disorders as a potential phenotypic trait marker of schizophrenia.

Association between electroencephalographic modulation, psychotic-like experiences and cognitive performance in the general population

AIM

An association between deficit of electroencephalographic (EEG) modulation during an odd-ball task and psychotic symptoms has been described in clinical samples, in agreement with the proposed role for altered salience in psychosis. To discard the possible influence of medication, the relationship between psychotic-like experiences and EEG modulation in the general population was explored.

METHODS

EEG and psychotic-like experiences were assessed in 194 healthy subjects during a P300 paradigm. EEG modulation was assessed as changes from pre-stimulus to response windows in spectral entropy (SE, a measurement of signal irregularity), median frequency (MF, a quantifier of the frequency distribution of oscillatory activity) and theta, alpha, beta-1, beta-2 and gamma relative power (RP, a summary of the distribution of spectral components).

RESULTS

A significant widespread decrease in SE and MF from baseline to response was found, with a significant increase in RP for theta and a decrease for higher frequency bands, supporting an increase in EEG regularity and a slowing of brain oscillations during the response. Furthermore, a significant association was found between SE modulation and distress of negative psychotic-like experiences, as well as between verbal memory and RP modulation for beta-1. Performance in verbal fluency was associated with the increase in theta RP during the response.

CONCLUSION

EEG irregularity of healthy subjects decreased at the expense of a larger contribution of theta RP and a decreased contribution of fast frequency bands. Subjects with smaller modulation showed poorer cognitive scores and greater distress of negative psychotic-like experiences.

A review of vulnerability and risks for schizophrenia: Beyond the two hit hypothesis

Schizophrenia risk has often been conceptualized using a model which requires two hits in order to generate the clinical phenotype-the first as an early priming in a genetically predisposed individual and the second a likely environmental insult. The aim of this paper was to review the literature and reformulate this binary risk-vulnerability model. We sourced the data for this narrative review from the electronic database PUBMED. Our search terms were not limited by language or date of publication. The development of schizophrenia may be driven by genetic vulnerability interacting with multiple vulnerability factors including lowered prenatal vitamin D exposure, viral infections, smoking intelligence quotient, social cognition cannabis use, social defeat, nutrition and childhood trauma. It is likely that these genetic risks, environmental risks and vulnerability factors are cumulative and interactive with each other and with critical periods of neurodevelopmental vulnerability. The development of schizophrenia is likely to be more complex and nuanced than the binary two hit model originally proposed nearly thirty years ago. Risk appears influenced by a more complex process involving genetic risk interfacing with multiple potentially interacting hits and vulnerability factors occurring at key periods of neurodevelopmental activity, which culminate in the expression of disease state. These risks are common across a number of neuropsychiatric and medical disorders, which might inform common preventive and intervention strategies across non-communicable disorders.

Age at first tobacco use and risk of subsequent psychosis-related outcomes: A birth cohort study

OBJECTIVE

Compared to the substantial body of research examining links between cannabis use and psychosis, there has been relatively little attention to the role of tobacco as a potential risk factor for psychosis. This study explored the association between age at first tobacco use and psychosis-related outcomes in a birth cohort.

METHOD

This study is based on a large birth cohort (the Mater-University Study of Pregnancy). At approximately 21 years of age, cohort members (N = 3752) were assessed for three psychosis-related outcomes (International Classification of Diseases non-affective psychosis, the presence of any hallucination and total count of delusional-like experiences) with the Composite International Diagnostic Interview and the Peters Delusional Inventory. Associations between age at first tobacco use and psychosis-related outcomes were examined using logistic regression in a model (a) adjusted for sex and age and (b) in a second model excluding all respondents who had a history of past problematic and current cannabis use.

RESULTS

When adjusted for age and sex, those who commenced tobacco at 15 years of age or younger were significantly more likely to (a) have non-affective psychosis, (b) be in the highest quartile of total score of the Peters Delusional Inventory and (c) report hallucinations. After excluding all those with a history of a cannabis use disorder, or who were current (last month) cannabis users, a significant association between age at first tobacco use and the presence of hallucinations persisted.

CONCLUSION

There is an association between age at first tobacco use and subsequent psychosis-related outcomes in young adults. While the findings cannot be used to deduce causality, it adds weight to the hypothesis that early tobacco use may contribute to the risk of developing psychosis-related outcomes.

Modulation of brain network parameters associated with subclinical psychotic symptoms

OBJECTIVE

Static deficits in small-world properties of brain networks have been described in clinical psychosis, but task-related modulation of network properties has been scarcely studied. Our aim was to assess the modulation of those properties and its association with subclinical psychosis and cognition in the general population.

METHOD

Closeness centrality and small-worldness were compared between pre-stimulus baseline and response windows of an odd-ball task in 200 healthy individuals. The correlation between modulation of network parameters and clinical (scores in the Community Assessment of Psychological Experiences) and cognitive measures (performance in the dimensions included in the Brief Assessment of Cognition in Schizophrenia battery) was analyzed, as well as between these measures and the corresponding network parameters during baseline and response windows during task performance.

RESULTS

In the theta band, closeness centrality decreased and small-worldness increased in the response window. Centrality and small-worldness modulation were, respectively, directly and inversely associated with subclinical symptoms.

CONCLUSIONS

A widespread modulation of network properties in theta band was observed, with a transient increase of small-worldness during the response window, compatible with a transiently more integrated cortical activity associated to cognition. This supports the relevance of electroencephalography to study of normal and altered cognition and its substrates. A relative deficit in the ability to reorganize brain networks may contribute to subclinical psychotic symptoms.

Mismatch negativity: Alterations in adults from the general population who report subclinical psychotic symptoms

BACKGROUND

Deficits of mismatch negativity (MMN) in schizophrenia and individuals at risk for psychosis have been replicated many times. Several studies have also demonstrated the occurrence of subclinical psychotic symptoms within the general population. However, none has yet investigated MMN in individuals from the general population who report subclinical psychotic symptoms.

METHODS

The MMN to duration-, frequency-, and intensity deviants was recorded in 217 nonclinical individuals classified into a control group (n=72) and three subclinical groups: paranoid (n=44), psychotic (n=51), and mixed paranoid-psychotic (n=50). Amplitudes of MMN at frontocentral electrodes were referenced to average. Based on a three-source model of MMN generation, we conducted an MMN source analysis and compared the amplitudes of surface electrodes and sources among groups.

RESULTS

We found no significant differences in MMN amplitudes of surface electrodes. However, significant differences in MMN generation among the four groups were revealed at the frontal source for duration-deviant stimuli (P=0.01). We also detected a trend-level difference (P=0.05) in MMN activity among those groups for frequency deviants at the frontal source.

CONCLUSIONS

Individuals from the general population who report psychotic symptoms are a heterogeneous group. However, alterations exist in their frontal MMN activity. This increased activity might be an indicator of more sensitive perception regarding changes in the environment for individuals with subclinical psychotic symptoms.

Comparing two basic subtypes in OCD across three large community samples: a pure compulsive versus a mixed obsessive-compulsive subtype

Due to its heterogeneous phenomenology, obsessive-compulsive disorder (OCD) has been subtyped. However, these subtypes are not mutually exclusive. This study presents an alternative subtyping approach by deriving non-overlapping OCD subtypes. A pure compulsive and a mixed obsessive-compulsive subtype (including subjects manifesting obsessions with/without compulsions) were analyzed with respect to a broad pattern of psychosocial risk factors and comorbid syndromes/diagnoses in three representative Swiss community samples: the Zurich Study (n = 591), the ZInEP sample (n = 1500), and the PsyCoLaus sample (n = 3720). A selection of comorbidities was examined in a pooled database. Odds ratios were derived from logistic regressions and, in the analysis of pooled data, multilevel models. The pure compulsive subtype showed a lower age of onset and was characterized by few associations with psychosocial risk factors. The higher social popularity of the pure compulsive subjects and their families was remarkable. Comorbidities within the pure compulsive subtype were mainly restricted to phobias. In contrast, the mixed obsessive-compulsive subtype had a higher prevalence and was associated with various childhood adversities, more familial burden, and numerous comorbid disorders, including disorders characterized by high impulsivity. The current comparison study across three representative community surveys presented two basic, distinct OCD subtypes associated with differing psychosocial impairment. Such highly specific subtypes offer the opportunity to learn about pathophysiological mechanisms specifically involved in OCD.

The validity of the Schizotypal Personality Questionnaire in a Greek sample: Tests of measurement invariance and latent mean differences

BACKGROUND

The Schizotypal Personality Questionnaire (SPQ) is a widely used scale for measuring schizotypal characteristics modeled on DSM-III-R criteria for schizotypal personality disorder (SPD). The aim of this study was to examine the factorial structure of the Greek SPQ, its factorial invariance across gender and different age groups and possible gender and age group differences at latent mean level.

METHODS

Eight hundred sixty-five community participants completed the Greek version of the SPQ.

RESULTS

With regard to the factorial structure of the original first-order model, the results showed that a seven-factor model (sub-scales "no close friends" with "constricted affect" and "ideas of reference" with "unusual perceptual experiences" were combined) was replicated adequately. Furthermore, the second-order "paranoid" model provided also adequate fit. With regard to the factorial invariance of the SPQ across gender and age, the analysis revealed that both, the first- and second-order models showed measurement invariance (configural, metric and structural) across gender and age groups (17-35 vs. 36-70). Latent mean differences across gender and age groups were also found.

CONCLUSIONS

Based on these findings, we can conclude that the Greek version of the SPQ is a psychometrically sound instrument for measuring schizotypal characteristics and a useful screening tool for SPD across gender and age.