Aspects Of Schizotypy Research Articles

Examining the impact of schizotypal personality traits on event-related potential (ERP) indexes of sensory gating in a healthy population.

The aim of this study was to better understand the relation of schizotypy traits with sensory gating ability in a sample of community-dwelling individuals with high and low schizotypy traits. Sensory gating was assessed through the paired click paradigm and mid-latency evoked responses (i.e., P50, N100, P200), while schizotypy traits were assessed through the SPQ-BR which was used to classify participants into "high" and "low" schizotypy groups. Based on prior work, we hypothesized that those with the highest schizotypy scores would have reduced sensory gating ability. While this study does not show differences between relatively low and high schizotypy groups on sensory gating ability, it does suggest that our participants may have been experiencing deficits in attention allocation, a downstream cognitive processing measure. Scores on the SPQ-BR suggest that our sample was not close to the high end of the schizotypy traits which may help explain why no differences were found. This research shows the importance of including all levels of schizotypy ratings in clinical research as we can gain a clearer view of the impact of schizotypy on the brain and cognitive functioning in those with "high" levels of schizotypy. Additionally, this work highlights the importance of including measures of important factors such as impulsivity and sensation-seeking to better understand what aspects of schizotypy may be driving these sensory gating alterations reported in the literature.

The association of schizotypal traits with Prepulse Inhibition: a double approach exploration

ABSTRACT Introduction: According to the fully-dimensional approach, schizotypy is a personality trait present in the population in a continuous manner while the quasi-dimensional approach emphasises its extreme presentations. In this study we examined the relationship between sensorimotor gating, a core risk-index of the schizophrenia-spectrum, and four schizotypal factors in a dimensional-wise and a dichotomising-wise approach. Methods: Two-hundred and eighty-three participants were assessed with the Schizotypal Personality Questionnaire and were tested for Prepulse Inhibition (PPI). Associations between the schizotypal factors and startle measures were examined with stepwise regressions (dimensional-wise approach). Individuals in the lower 20% or the upper 20% for each schizotypal factor were identified and between-group comparisons were conducted (dichotomising-wise approach). Results: We found that with both approaches, only high paranoid or negative schizotypy were associated with reduced PPI. The low negative schizotypy group had prolonged onset and peak latencies, indicating that prolonged stimulus detection accompanies superior sensorimotor gating in this group. Conclusions: The findings suggest that although differentiating the effects of the various schizotypal factors is primary, the approach employed is secondary. The study also adds evidence in the literature supporting PPI as a useful endophenotypic marker of the schizophrenia-spectrum and highlights the contribution of specific aspects of schizotypy.

Editorial: Endophenotypes for Schizophrenia and Mood Disorders: Implications from Genetic, Biochemical, Cognitive, Behavioral, and Neuroimaging Studies.

Editorial: Endophenotypes for Schizophrenia and Mood Disorders: Implications from Genetic, Biochemical, Cognitive, Behavioral, and Neuroimaging Studies.

Season of birth, mixed-handedness, and psychometric schizotypy: Preliminary results from a prospective study

Season of birth and hand preference were examined in a sample of 42 (7 males, 35 females) individuals who were identified as schizotypic based on their scores on selected scales of the Chapman Psychosis Proneness Scales (CPPS) and a matched comparison sample of 42 individuals with non-deviant CPPS scores. Presence or absence of schizotypy was analyzed using chi square tests of independence with the presence or absence of each risk factor serving as the independent variable. Further analyses incorporated independent means t tests to examine mean scores on the CPPS with the presence or absence of each risk factor again serving as the independent variable. Results supported the hypothesis that winter/early-spring birth would be associated with psychometric schizotypy, although the results for mixed-handedness fell just short of statistical significance. However, mixed hand preference was associated with higher scores on MagId and PerAb scales of the CPPS, but not the RSA scale, which suggests that mixed laterality is associated with the more cognitive-perceptual aspects of schizotypy. Results are discussed in relation to previous literature and their relevance to the prediction of schizophrenia-related psychosis.

Theory of Mind and psychometric schizotypy

The extent to which Theory of Mind impairments are a trait associated with schizotypy is unclear. To date, findings have been mixed. We compared two groups of psychometrically identified schizotypes, namely, those characterized by positive schizotypy (perceptual aberrations and magical ideation; n = 36) and those characterized by negative schizotypy (social anhedonia; n = 30) to a low schizotypy comparison group ( n = 68) in terms of their Theory of Mind performance. Theory of Mind was assessed in two ways: a composite Hinting Task and the Reading the Mind in the Eyes Test. The groups were also compared in terms of their self-reported levels of referential thinking. Our results indicate that individuals characterized by positive schizotypy show Theory of Mind deficits, as measured by the Hinting Task. The three groups did not differ in terms of the Eyes Test. Referential thinking was significantly associated with the Eyes Test but not the Hinting Task. Overall these findings suggest that different aspects of schizotypy are associated differentially with Theory of Mind deficits. The results also provide further rationale for the inclusion of multiple tasks when attempting to study multifaceted constructs such as Theory of Mind.

Schizotypy, delusional ideation and well‐being in an American new religious movement population

This study extends two previous UK studies that looked at schizotypy in new religious movements (Peters, Day, McKenna & Orbach, 1999a; Day & Peters, 1999) using a similar religious subgroup from a different culture. A sample of American Hare Krishna devotees was compared with a non-religious control group on measures of delusional ideation, schizotypy and general well-being. The Hare Krishna group scored significantly higher than the control group on delusional ideation, but not other aspects of schizotypy or general well-being. They also scored higher on delusional conviction, but not distress and preoccupation. The findings provide cross-cultural confirmation for the notion of a continuum between normality and delusional thinking, and the need to consider delusional beliefs as multi-dimensional-psychological health seems to be predicated not on what you believe, but how you believe it.

A Bias Against Disconfirmatory Evidence Is Associated With Delusion Proneness in a Nonclinical Sample

Previous work has suggested that a bias against disconfirmatory evidence (BADE) may be associated with the schizophrenia spectrum. The current investigation focused on whether a BADE (1) overlaps with traditional measures of memory and executive functions or selectively taps into a unique aspect of cognition and (2) is correlated with delusional ideation but not with other aspects of schizotypy. Sixty-eight undergraduate students were administered the Schizotypal Personality Questionnaire (SPQ), the BADE test, the Rey Auditory Verbal Learning Test (RAVLT), the Wisconsin Card Sorting Test (WCST), the Trail Making Tests A and B (TMT), and tests used to estimate IQ. Factor analysis of all cognition measures resulted in a 6-factor solution, 4 of which reflected the 4 domains of neuropsychological tests (WCST, RAVLT, TMT, and IQ), and 2 of which reflected different aspects of the BADE test: Initial Belief and Integration of Disconfirmatory Evidence. This solution suggests that BADE measures were independent from the other cognitive domains measured. Integration of Disconfirmatory Evidence was the only factor that correlated with delusion-content subscales of the SPQ, providing support for the contribution of a BADE to delusional ideation.

Low self-directedness (TCI), mood, schizotypy and hypnotic susceptibility

Relationships between personality and mood variables in a non-clinical sample were investigated using 80 medical students divided into two groups according to their Self-directedness (SD) scores from Cloninger’s Temperament and Character Inventory (TCI). Those with low SD proved to have significantly raised scores on hypnotisability, absorption, Self-transcendence and significantly lower scores on Co-operativeness. Both the schizotypal variables of Cognitive Activation and Withdrawal were raised. Further, the combination of low SD, low Co-operativeness and high Self-transcendence points also towards a schizotypal personality style. These results corroborate a previously established link between schizotypy and hypnotic susceptibility. Low scorers on SD also had significantly higher mood distress, anxiety and perceived stress. Low SD, with its history of identifying personality disorders, in this data set appeared to be identifying those medical students who were distressed in all measured aspects of mood as well as having indications of higher levels of absorption, hypnotic susceptibility and aspects of schizotypy. The generality of distress shown by these students raises important questions about their eventual competency in communication skills and, indeed, decision making when they graduate as doctors involved in the treatment of patients.

Thought-action fusion and schizotypy in undergraduate students.

To examine the relationship between thought-action fusion (TAF) and schizotypy. In two separate samples of undergraduate students (Ns = 77 and 64), correlations were computed between a measure of TAF and indices of schizotypy and fantasy proneness. Positive correlations were found between TAF and various aspects of schizotypy (i.e. perceptual aberration, magical ideation, schizotypal personality characteristics, disposition to hallucinate). However, correlations between TAF and schizotypy no longer attained significance when controlling for fantasy proneness. At least in the non-clinical population, the connection between TAF and schizotypy seems to be a by-product of fantasy-prone individuals' tendency to report unusual experiences.

The factorial structure of schizotypy: Part II. Cognitive asymmetry, arousal, handedness, and sex.

We replicate relations between factors of schizotypy and cognitive asymmetry patterns assessed with recognition memory for words versus faces, and with arousal levels assessed with self-report scales. The withdrawn factor or subscales of loneliness and constricted affect were associated as before with a right hemisphere, face advantage asymmetry, as was physical anhedonia in males. Subjects with the opposite asymmetry and those high on the active factor--eccentricity and odd speech--had high self-report activation scores. These relations better characterized males who also had higher scores on the asymmetry-related factors. Females had higher scores on the third unreality factor--unusual perceptions and odd beliefs--which showed inconsistent relations with cognitive asymmetry. Non-right-handedness was associated with both hemisphere asymmetry patterns suggesting that the structural mechanism responsible for non-right-handedness is associated with bidirectional hemispheric functional imbalance. The results support the importance of patterns of functional asymmetry in underpinning different aspects of schizotypy.

A scale for the measurement of schizotypy

This paper reports the development of a short scale for the measurement of two aspects of schizotypy for use in general population studies. It was intended for use particularly in a ‘high-risk’ study in Mauritius but only the development of the scale in Britain is described in this paper. The two aspects measured are those concerned with cognitive/perceptual/attentional function, on the one hand; and social dysfunction and anhedonia, and physical anhedonia on the other. These might be called the ‘positive’ and ‘negative’ aspects of schizotypy, possibly having some parallels to the postive and negative symptoms of schizophrenia. The work described indicates that both aspects can be measured with reliability and with stability of factor structure from study to study. A number of studies are described in which the questionnaire, or earlier versions of it are used. These all indicate that the scales have good construct validity.

The measurement of schizotypy in Mauritius

Data are presented on the development and use of a short scale for measuring two aspects of schizotypy in research in Mauritius. The work described largely replicates the use of the same scale in Britain. The factor structure, reliability and validity of the Schizophrenism section of the scale are similar in Mauritius and Britain. However, although the structure of the Anhedonia section is comparable in Mauritius and Britain the reliability of the Mauritian version is lower than with British samples.