P50 sensory gating deficits in schizotypy

Sensory gating is the ability to filter out irrelevant stimuli from the environment. Individuals with schizophrenia consistently demonstrate deficits in this ability leading to sensory overload and cognitive fragmentation. This dysfunction has also been found in schizotypy, which is defined as a manifestation of nonclinical symptoms qualitatively similar to those found in schizophrenia. In the present study, auditory sensory gating was assessed in healthy individuals by testing the attenuation of the P50 event-related potential. The degree of suppression was then correlated with schizotypy by using the O-LIFE questionnaire. Relative to the low-scoring individuals, P50 suppression was significantly reduced in those with high levels of schizotypy. Furthermore, the degree of deficit in P50 gating correlated with both cognitive disorganisation and impulsive nonconformity dimensions of schizotypy. These results suggest that schizotypal individuals may have early sensory gating deficits similar to schizophrenia patients, especially if they display a disorganised or impulsive profile. As they do not exhibit overt psychotic symptoms, it is likely that such deficits represent an underlying core cognitive dysfunction within the schizophrenia spectrum.     

Lateralisation of language and emotion in schizotypal personality: Evidence from dichotic listening

Striking disturbances have been reported in language and emotional prosody processing by patients diagnosed with schizophrenia. In view of this and of research suggesting that schizotypal personality traits can also be expressed sub-clinically, the present study aimed to discover whether similar disturbances would be reflected in cognitive laterality patterns when symptoms of schizotypy are present yet at a non-clinical level. A dichotic listening task was used to examine the sensitivity and speed with which 132 right-handed participants (85 females and 47 males, mean age = 32.44, SD = 12.29) detected both words and emotional prosody, all of whom also completed the Schizotypal Personality Questionnaire. Findings indicated that both high (n = 64) and low (n = 68) schizotypy groups demonstrated the typical right ear advantage for the detection of words and left ear advantage for the detection of emotional prosody. Individuals with higher schizotypal personality scores also demonstrated poorer sensitivity in detecting emotional prosody. These results reveal that within the healthy population, higher levels of schizotypy are not associated with the atypical lateralisation of language and emotion. Nevertheless, the existence of these symptoms does signal the presence of shared characteristics with the clinical sphere, namely poorer emotion recognition performance.     

Schizotypy and verbal memory in the adolescent general population

The following study examines the relationship between verbal memory deficits and schizotypal traits measured psychometrically from a non- clinical adolescent population. In this transversal analytical study participated 139 subjects. They were secondary school students, with ages ranging from 13 to 16 years old (mean= 14, 35; Sta.Dev.= 0, 548). After administrating the scales O-LIFE (psychometrical schizotypy), CVLT (verbal memory), and Letters and Numbers subtest of WAIS-III (working memory), data was analyzed utilizing Pearson correlations and mean comparison test. Results showed lack of relations between schizotypy measures and working memory. Nonetheless, some of the O-LIFE dimensions correlated with verbal memory. These findings support partly the literature reviewed. Yet, more work focused on schizotypy and cognitive deficits as risk factors are suggested.     

Logical reasoning in schizotypal personality

It was examined whether psychotic-like personality traits in a sample of 205 college students could predict logical reasoning deficits, akin to those seen in schizophrenia. The participants were tested on their ability to assess the logical validity of premises (Logical Reasoning Task), and completed a multi-dimensional schizotypy inventory (O-LIFE). Low accuracy was associated with increased levels of disorganized schizotypy (‘Cognitive Disorganization’), while elevated errors were associated with increased levels of positive (‘Unusual Experiences’), negative (‘Introvertive Anhedonia’) and impulsive (‘Impulsivity Non-conformity’) schizotypy. Nevertheless, multiple regression analyses revealed that negative schizotypy was retained as the only significant predictor after performance was corrected for random guessing, and the contribution of the average amount of time spent on each premise was controlled. The results suggest that, although most schizotypy dimensions have a detrimental effect on reasoning performance, possibly due to disadvantageous test-taking strategies, negative schizotypy is the most reliable predictor of logical reasoning deficits. It is proposed that social/interpersonal schizotypal traits, like negative symptoms of schizophrenia, are accompanied by deficient executive functions of working memory, which appear to undermine, inter alia, logical reasoning processing.     

The relationship between measures of creativity and schizotypy

The aim of this study was to determine the extent to which a measure of multidimensional schizotypy and intelligence predicted measures of creativity, as assessed by self-rated creativity, a measure of the creative personality (CPS: Gough, 1979) and an inventory of creative behaviours. Additionally an aggregation of the three different measures; total creativity was examined. 140 participants completed the creativity measures, a general intelligence test (Wonderlic Personnel Test: Wonderlic, 1992) in addition to a multidimensional schizotypy inventory (O-LIFE: Mason, Claridge, & Jackson, 1995). The Unusual Experiences and Impulsive Nonconformity dimensions of the O-LIFE were positively and significantly related to creativity. The Cognitive Disorganisation dimension was found to be negatively and significantly related to creativity. The implications of the findings were discussed.     

Confirmatory factor analysis of the three-factor structure of the schizotypal personality questionnaire and Chapman schizotypy scales

We examined the factor structure of the Schizotypal Personality Questionnaire (SPQ; Raine, 1991), using confirmatory factor analysis in 3 experiments, with an aim to better understand the construct of schizotypy. In Experiment 1 we tested the fit of 2-, 3-, and 4-factor models on SPQ data from a normal sample. The paranoid 4-factor model fit the data best but not adequately. Based on the strong basis for the Raine 3-factor model we attempted to improve the fit of the 3-factor model by making 3 modifications to the Raine model. These modifications produced a well-fitting model. In Experiment 2 the good fit of this modified 2-factor model to SPQ scores was replicated in an independent normal sample. In Experiment 3, the modified 3-factor model was successfully extended to include the 3 Chapman schizotypy scales. Together these 3 experiments indicate that the 3-factor model of the SPQ, albeit with some slight modifications, is a good model for schizotypy structure that is not restricted to 1 measure of schizotypal personality traits.     

Individual differences in language lateralisation,schizotypy and the remote-associate task

We tested the hypothesis that the level of reduced laterality in language is correlated with the degrees of schizotypal personality in healthy individuals and with their performance in the remote-associate task (RAT). A total of 53 healthy participants completed a schizotypal personality measure of the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE; a questionnaire measuring the level of psychotic proneness), a consonant–vowel–consonant (CVC; requiring the identification of letter trigrams presented tachistoscopically in the left/right visual fields or both), measuring reduced language laterality and a remote-associate task (RAT; requiring to report a word, weakly associated with three cue words). Analysis revealed correlations between CVC and O-LIFE, as well as between CVC and RAT performance. The results suggest that reduced language lateralisation (reduced hemispheric integration) may play a role in schizophrenic language disorganization, as reflected in highly schizotypal individuals, and that hemispheric integration plays a role in the remote-associate task.     

Skin-conductance orienting deficits and increased alcoholism in schizotypal criminals.

This study tested the interaction hypothesis that a subgroup of criminals with schizotypal personality would show skin-conductance orienting deficits and increased alcoholism. In a prospective, longitudinal study of alcoholism in 134 males, schizotypy was assessed during adolescence, skin-conductance orienting was assessed at ages 18-20 years, and criminal offending and alcohol abuse were assessed at ages 30-33 years. A significant interaction between schizotypy and criminality indicated that schizotypal criminals were characterized by autonomic orienting deficits. Furthermore, the rate of alcoholism in schizotypal criminals (54.8%) was significantly higher than in criminals (23.8%), schizotypal noncriminals (13.9%), and comparisons (21.7%). It is argued that schizotypal criminals are a relatively distinct group and that prefrontal dysfunction may underlie both orienting deficits and alcoholism in this group.     

Do sex differences in emotionality mediate sex differences in traits of psychosis-proneness?

The aim of the study was to determine if sex differences in emotionality might account for sex differences in distinct traits of proneness to psychosis (or "schizotypy"). Females report higher levels of "positive" schizotypy (e.g., magical thinking) than males, along with a tendency toward greater schizotypal disorganisation, whereas males report higher levels of "negative" schizotypal traits, such as social anxiety (Jackson & Claridge, 1991; Raine, 1992). Given the affect-oriented nature of "negative" schizotypal traits, we tested the hypothesis that higher levels of "negative" schizotypy among males would be accounted for by more general sex differences in emotionality; that is, by less frequent and less intense emotional experiences. A total of 81 student participants were administered the Cognitive-Perceptual Deficits, the Disorganisation, and the Interpersonal Deficits components of Raine's (1991) Schizotypal Personality Questionnaire (SPQ), indexing respectively, "positive" schizotypy, schizotypal disorganisation, and "negative" schizotypy. Frequency of emotional experience was assessed using the Emotionality subscale (Buss & Plomin, 1984) and intensity, the Affect Intensity Measure (Larsen & Diener, 1987). As predicted, males scored significantly higher than females on the SPQ Interpersonal Deficits component but no sex differences emerged for the other two components. Males reported significantly less intense, although not less frequent, experiences than females. A reduced intensity of positive emotions in particular was found to mediate the sex difference in "negative" schizotypy. Our results suggest that a less intense experience of positive affect might contribute to males' propensity to develop negative symptoms should a schizophrenic breakdown occur.     

Is Fear of Others Linked to an Uncertain Sense of Self? The Relevance of Self-Worth, Interpersonal Self-Concepts, and Dysfunctional Beliefs to Paranoia

The assumption that a low sense of self-worth can give rise to paranoid delusions is relevant from a therapeutic perspective, but research has been inconsistent. The present study sought to investigate how interpersonal self-concepts and global self-worth relate to psychotic and depressive psychopathology in persons with psychosis. Participants with psychosis (n = 83) and healthy controls (n = 33) were assessed for global self-worth, interpersonal self-concepts, and dysfunctional beliefs using the Frankfurt Self-Concept Scale and the Dysfunctional Attitude Scale. Symptoms were assessed with the Positive and Negative Syndrome Scale, the Peters et al. Delusions Inventory, the Paranoia Checklist, and the Beck Depression Inventory. We hypothesized that perceived threat to self-worth, as expressed in dysfunctional acceptance beliefs and negative interpersonal self-concepts, would be uniquely associated with persecutory delusions. In contrast, low global self-worth would be strongly associated with symptoms of depression. Multiple regression analyses were used to investigate the association between symptoms and self-concepts. As expected, low global self-worth was associated with depression, whereas the more specific perception of not being accepted by relevant others was most clearly related to psychotic symptoms. Almost half of the variance in paranoia scores was explained by negative interpersonal self-concepts and the interaction between negative interpersonal self-concepts and dysfunctional acceptance beliefs. Thus, cognitive interventions for delusions might be improved by focusing more on interpersonal self-concepts.     

Psychosis proneness and clinical psychopathology: examination of the correlates of schizotypy

The present report examined the associations between the Perceptual Aberration Scale (PAS), a prominent psychometric index of hypothetical psychosis proneness, and several measures of clinical psychopathology in a nonpsychotic psychiatric sample (N = 101). Patients were examined by experienced clinicians using structured psychiatric interviews to assess DSM-III-R Axis I and II conditions and rated for anxiety, depression, severity of illness, and current adult social competence. Elevated scores on the PAS were most closely associated with anxiety and depression as well as schizotypal, schizoid, avoidant, and obsessive-compulsive personality disorder symptomatology. Hierarchical regression analysis identified schizotypal symptoms and anxiety as the two underlying psychopathological processes most useful in explaining variance in PAS scores. Results are interpreted as supporting both the clinical relevance and research utility of the PAS and enhancing the construct validity of Meehl's model of schizotypy.     

Schizotypal personality traits and attitudes towards Hinduism among Balinese Hindus

The study explored the relationship between schizotypal personality traits and attitude of Hindus towards their faith. A total of 309 Balinese Hindus responded to the Santosh–Francis Scale of Attitude towards Hinduism, the Schizotypal Personality Questionnaire Brief, and a number of external indicators and religious practices. Attitude towards Hinduism, frequency of prayer, and temple attendance had a rather weak positive relationship with each other, while prayer behaviour exhibited negative low-to-moderate relationships with schizotypal traits. A hierarchical multiple linear regression model identified the disorganised elements of schizotypy as the primary predictor of the attitude towards Hinduism. Finally, age showed negative associations with schizotypy and positive ones with Hinduism, while women were less schizotypal and had more positive attitude towards their faith than men. These findings suggest the presence of both underlying cross-faith elements and the strong influence of faith- and culture-specific forces on the relationship between religiosity and schizotypy.     

A confirmatory factor analysis of the structure of schizotypy

Recent research into schizotypal traits has been concerned with the number and nature of these personality dimensions. Earlier exploratory factor analytic work using a wide variety of scales (the CSTQ) has generated a four-factor solution but other solutions have been provided by other investigators. This study uses confirmatory factor analysis on a large sample to compare several plausible models of the relationships between scales. These models include a two-factor model separating ‘positive’ from ‘negative’ schizotypal features, a three-factor model including features of cognitive disorganization, and the four-factor model generated previously by exploratory factor analysis. Results offer support for the four-factor solution as the only structure meeting multiple criteria for goodness of fit. The relevance of Eysenck's dimensions, and the P scale in particular, to the results is discussed. Attention is drawn to the possibility that the factors describe predispositions of risk of psychotic disorders beyond that of schizophrenia.     

Collective estimation: Accuracy,expertise, and extroversion as sources of intra-group influence

Although estimations typically possess correct answers, these answers may be difficult to demonstrate to others. However, providing external information may increase their demonstrability. In this experiment, individuals (N = 60) and 6-person groups (N = 360) generated estimations with or without frames of reference. We hypothesized that estimations involving frames of reference would be best fit by models predicting intra-group influence based on the accuracy of alternatives or of members in general. Conversely, we hypothesized that estimations not involving frames of reference would be best fit by models predicting influence based on member extroversion or proposal centrality. Results indicate that groups outperformed individuals and that estimations generated in the presence of frames of reference were superior to those generated in their absence. Accuracy and expertise schemes provided the best fit when frames of reference were provided, whereas an extroversion scheme provided the best fit when they were not.     

Validation of the Multidimensional Schizotypy Scale-Brief in Two Large Samples

This study reports on an initial examination of the construct validity of the Multidimensional Schizotypy Scale-Brief (MSS-B) and the first investigation of its psychometric properties outside of its derivation samples. The MSS-B contains 38 items that assess positive, negative, and disorganized schizotypy and has comparable content coverage and psychometric properties as the original 77-item Multidimensional Schizotypy Scale. Two large samples (n?=?1430 and 1289) completed the MSS-B, as well as measures of schizotypal personality traits and the Five-Factor Model of Personality. MSS-B scores were computed from the full-length scale in sample 1, whereas participants in sample 2 were administered the MSS-B. The psychometric properties and intercorrelations of the MSS-B subscales were consistent with findings from the original derivation samples, with no shrinkage in reliability. In terms of relations with schizotypal traits, the MSS-B positive schizotypy dimension had its strongest association with cognitive-perceptual schizotypal traits, MSS-B negative schizotypy had its strongest association with interpersonal schizotypal traits, and MSS-B disorganized schizotypy had its strongest association with disorganized schizotypal traits. The schizotypy dimensions were characterized by hypothesized patterns of distinct associations with the Five-Factor Model. The present findings are consistent with results from the full-scale MSS.     

Integrating the Interpersonal Psychological Theory of Suicide Into the Depression/Suicidal Ideation Relationship: A Short-Term Prospective Study

We examined the hypothesis that depressive symptoms are associated with increased beliefs about perceived burdensomeness and thwarted belongingness identified in the interpersonal psychological theory of suicide and that these beliefs are associated with changes in suicidal ideation. Participants with clinical levels of depressive symptoms (n = 299) were selected from a larger group (n = 508) and completed measures of depressive symptoms, perceived burdensomeness and thwarted belongingness, and suicidal ideation twice over a period of 2 months. Results of a structural equation model found that depressive symptoms were associated with increases in burdensomeness and lack of belonging, which were associated with suicidal ideation. Moreover, this hypothesized integrated model demonstrated a significantly better fit than an alternative model that assumed burdensomeness and lack of belonging were associated with changes in depressive symptoms, which were associated with suicidal ideation. Our findings suggest that the well-established relationship between depressive symptoms and suicidal ideation is associated with changes in beliefs that one is a burden on others and lacks belonging. More generally, these results suggest that it may be fruitful to integrate theories of suicide risk to form a comprehensive model that can inform future research and clinical interventions.     

Religious experience,religious orientation and schizotypy

The present study examined the relationship between religious orientation and schizotypy, with the prediction that intrinsic religiosity would be negatively associated with schizotypy, and religious experience and extrinsic religiosity would be positively associated with schizotypy. A total of 308 UK adults (132 men; 176 women) completed measures of religious experience, intrinsic orientation towards religion, extrinsic orientation towards religion, schizotypal personality traits and borderline personality. Though the present findings also suggest that the significant relationships between religiosity and schizotypy traits are fragmented, particularly by sex, the findings are consistent with theory that an intrinsic orientation towards religion is associated with lower levels of schizotypy, and religious experience and an extrinsic orientation towards religion is associated with higher levels of schizotypy.     

The Relationship Between Nonclinical Schizotypy and Handedness on Divergent and Convergent Creative Problem-Solving Tasks

Previous research indicated a relationship between hemispherical dominance, the extent of schizotypal tendencies, and creativity. Little research has been conducted to assess the degree of schizotypy in nonclinical samples. The aim of this study was to determine the extent to which measures of multidimensional schizotypy and predominant handedness could predict measures of creativity, as assessed by both divergent and convergent tasks. One hundred and twenty-six participants participated in a quasi-experiment involving tests of predominant handedness, schizotypal tendencies, and divergent and convergent thinking. Results suggest that individuals who scored high on a test for schizotypal tendencies performed better on divergent problem-solving tasks, as opposed to low scoring individuals who performed better on convergent problem-solving tasks. Furthermore, results suggest that there was relationship between handedness on divergent and convergent thinking. There was, however, a relationship between handedness (right hemisphere) on the degree of schizotypal tendencies with left-handed individuals demonstrating greater schizotypal tendencies.     

Schizotypy and sustained attention: confirming evidence from an adult community sample

Sustained attention deficits represent one of the most robust findings in the study of schizophrenia and schizotypy. However, very little is known about the nature of sustained attention performance and schizotypy in the general adult population. The present study assessed sustained attention performance in a large, normative adult community sample (N = 305) with no history of psychosis using the Continuous Performance Test-identical pairs version (CPT-IP). Associations between overall CPT-IP performance and schizotypal personality disorder features, controlling for the effects of age, sex, and educational level, revealed diminished sensitivity (d', discriminability), and increased random errors were related to increased reality distortion features. These data, drawn from a general population sample, provided support for overall sustained attention deficits as an endophenotype for schizophrenia liability.     

Peer victimization as a risk factor for schizotypal personality in childhood and adolescence

There has been no prior research on peer victimization and child or adolescent schizotypal personality. This study tests the hypothesis that increased peer victimization is associated with increased schizotypal personality. Schizotypy was assessed using the SPQ-C (Schizotypal Personality Questionnaire-Child) in 3,508 male and female schoolchildren aged 8 to 16 years. All forms of peer victimization (physical, verbal, social manipulation, attack on property) were associated with schizotypal personality in both males and females across all age groups. Significant victimization more than doubled schizotypy scores. It is hypothesized that peer victimization may predispose to paranoid ideation, social anxiety, and lack of close friends, and consequently heightened schizotypal personality.