Schizotypy Traits Research Articles

Are the Autism and Positive Schizotypy Spectra Diametrically Opposed in Empathizing and Systemizing?

Crespi and Badcock's (Behaviour Brain Sci 31: 241-261, 2008) novel theory, which presents autism and positive schizophrenia as diametrical opposites on a cognitive continuum, has received mixed support in the literature to date. The current study aimed to further assess the validity of this theory by investigating predictions in relation to empathizing and systemizing. Specifically, it is predicted by Crespi and Badcock that while mild autistic traits should be associated with a cognitive profile of superior mechanistic cognition (which overlaps with systemizing) but reduced mentalistic cognition (which overlaps with empathizing), positive schizotypy traits should be associated with the opposite profile of superior mentalistic but reduced mechanistic cognition. These predictions were tested in a student sample using a battery of self-report and behavioural measures. The pattern of results obtained provides no support for Crespi and Badcock's theory.

Poster #256 SOCIAL COGNITIVE BIASES AS MODERATORS AND MEDIATORS OF SUCCESSFUL COGNITIVE – BEHAVIOURAL THERAPY IN SCHIZOPHRENIA – RESULTS OF THE POSITIVE STUDY

Individuals with schizophrenia exhibit impairments in multiple social cognitive domains. There is evidence that these impairments may be trait-related vulnerability markers for schizophrenia. However, the literature focusing on individuals vulnerable to developing schizophrenia-spectrum disorders, referred to as schizotypy, has produced inconsistent findings. This study's primary aim was to provide a more comprehensive understanding of social cognitive functioning within schizotypy than previous studies by employing a broad array of measures to assess multiple social cognitive domains, and examine how these domains relate to specific schizotypy traits (i.e., positive, negative, and disorganized) and Quality of Life (QOL). Facial emotion recognition, Theory of Mind (ToM), and aspects of emotional intelligence related to regulating one's own emotions (emotion management) and other's emotions (social management) were measured. Individuals with psychometrically defined schizotypy (n=36) and controls (n=26) were examined. The schizotypy group performed significantly worse than controls on facial emotion recognition, ToM, and emotion management, but not social management. Generally speaking, poorer social cognition performance was not a function of specific schizotypy traits. However, negative traits were associated with poorer facial emotion recognition, and disorganized traits were associated with better social management. Facial emotion recognition was associated with QOL in the schizotypy group.

Cognitive and subjective effects of mephedrone and factors influencing use of a ‘new legal high’

Use of the stimulant drug mephedrone increased dramatically in 2009, and it is still available in the United Kingdom after being controlled in April 2010. This study aimed to assess mephedrone's acute cognitive and subjective effects. A mixed within- and between-subjects design compared 20 mephedrone users, first while intoxicated (T1) and secondly drug free (T2); and 20 controls twice when drug free (T1 and T2). Participants' own homes. Healthy adults recruited from the community. Subjective effects, episodic and working memory, phonological and semantic fluency, psychomotor speed and executive control at were assessed at T1 and T2. Trait schizotypy, depression, changes in mephedrone use since the ban and attitudes influencing use of a hypothetical new legal high were indexed at T2 only. Compared with controls, mephedrone users had generally impaired prose recall (P = 0.037) and higher scores in schizotypy (P < 0.001) and depression (P = 0.01). Mephedrone acutely primed a marked 'wanting' for the drug (P < 0.001), induced stimulant-like effects, impaired working memory (P < 0.001) and enhanced psychomotor speed (P = 0.024). Impulsivity in mephedrone users correlated with the number of hours in an average (nearly 8 hour) mephedrone session (r = 0.6). Users would be drawn to use a new legal high if it were pure, had no long/short term harms, and was positively rated by friends or on the internet. Mephedrone impairs working memory acutely, induces stimulant-like effects in users and is associated with binge use. Factors that influence users' attitudes to new drugs might help to predict future trends in use of the many new psychoactive substances emerging on the internet.

Investigating the interaction between schizotypy, divergent thinking and cannabis use

Cannabis acutely increases schizotypy and chronic use is associated with elevated rates of psychosis. Creative individuals have higher levels of schizotypy, however links between cannabis use, schizotypy and creativity have not been investigated. We investigated the effects of cannabis smoked naturalistically on schizotypy and divergent thinking, a measure of creativity. One hundred and sixty cannabis users were tested on 1 day when sober and another day when intoxicated with cannabis. State and trait measures of both schizotypy and creativity were administered. Quartile splits compared those lowest (n=47) and highest (n=43) in trait creativity. Cannabis increased verbal fluency in low creatives to the same level as that of high creatives. Cannabis increased state psychosis-like symptoms in both groups and the high creativity group were significantly higher in trait schizotypy, but this does not appear to be linked to the verbal fluency change. Acute cannabis use increases divergent thinking as indexed by verbal fluency in low creatives.

Schizophrenia Candidate Gene ERBB4: Covert Routes of Vulnerability to Psychosis Detected at the Population Level

Prior genetic and functional evidence established ERBB4 as a probable schizophrenia susceptibility gene that may confer risk via modulating brain information processing dependent on the integrity of frontotemporal brain circuitry. Utilizing retrospective data drawn from the cross-sectional population-based Athens Study of Psychosis Proneness and Incidence of Schizophrenia (ASPIS) (n = 1127), we attempted to independently replicate and further extend previous findings by examining the effects of ERBB4 gene variants on 3 broad population-based psychosis-related phenotypes: verbal working memory (VWM), trait schizotypy, and stress-induced subclinical psychotic experiences (PE). Three common ERBB4 single nucleotide polymorphisms that were previously associated with schizophrenia and impaired frontotemporal-related information processing (rs7598440, rs839523, and rs707284), their haplotypes, and corresponding diplotypes were tested. VWM performance was significantly associated with rs839523 and rs707284 markers even after correction for multiple testing, thus validating reported findings that have implicated ERBB4 gene variation on working memory. No associations were detected between these ERBB4 variants and trait schizotypy. However, we were able to detect a significant effect of rs7598440 marker on PE expressed under stressful environmental conditions. Combined haplotype analysis of the above 3 markers, identified a "yin-yang" pattern of association, confirmed at the diplotype level. While GGG haplotype homozygotes were associated with "protective" effects on VWM performance and PE, AAA "risk" haplotype carriers were associated with worse VWM performance and simultaneously exhibited significantly elevated PE. This dual, possibly pleiotropic, impact on frontotemporal circuitry and increased sensitivity to psychosocial stress may represent subtle manifestations of ERBB4-related vulnerability to psychosis, expressed at the population level.

Poorer Wisconsin card‐sorting test performance in healthy adults with higher positive and negative schizotypal traits

Non-clinical schizotypy was found to be related to poorer Wisconsin Card-Sorting Test (WCST) performance, but the results were inconsistent. Two subgroups, the higher negative-higher positive and the lower negative-lower positive (15 vs 16), were selected from the top and the bottom quartiles of negative and positive scale scores of the Schizotypal Personality Questionnaire (SPQ) completed by 177 healthy volunteers, respectively. The higher negative-higher positive SPQ score subgroup had significantly poorer performance regarding the completed categories of WCST than the lower negative-lower positive SPQ score subgroup. Subjects with higher non-clinical schizotypy trait showed relatively mild cognitive dysfunction.

Evaluation of state and trait biomarkers in healthy volunteers for the development of novel drug treatments in schizophrenia

Antipsychotic drugs are the mainstay of treatment for schizophrenia but they have little effect on core negative symptoms or cognitive impairment. To meet the deficiencies of current treatments, novel potential compounds are emerging from preclinical research but translation to clinical success has been poor. This article evaluates the possibility that cognitive and physiological abnormalities in schizophrenia can be used as central nervous system biomarkers to predict, in healthy volunteers, the likely efficacy of entirely new pharmacological approaches to treatment. Early detection of efficacy would focus resource on rapidly developing, effective drugs. We review the relevance of selected cognitive and physiological abnormalities as biomarkers in schizophrenia and three of its surrogate populations: (i) healthy volunteers with high trait schizotypy; (ii) unaffected relatives of patients; and (iii) healthy volunteers in a state of cortical glutamate disinhibition induced by low-dose ketamine. Several biomarkers are abnormal in these groups and in some instances there has been exploratory work to determine their sensitivity to drug action. They are generally insensitive to current antipsychotics and therefore their predictive validity cannot be established until novel, therapeutically useful drugs are discovered. Until then such biomarker studies can provide evidence of drugs engaging with the mechanism of interest and encouragement of the concept.

Understanding Constricted Affect in Schizotypy Through Computerized Prosodic Analysis

Constricted affect (CA) is a cardinal negative symptom of schizophrenia-spectrum disorders. It is unclear whether behaviorally-defined CA occurs in individuals with schizotypy-those with the personality organization reflective of schizophrenia liability. Moreover, it is unclear whether CA contributes to real world dysfunction in this population. The present study employed computerized prosodic analysis of natural speech procured during a laboratory procedure. Subjects were 89 individuals with psychometrically-defined schizotypy and 26 controls. Groups did not differ in any of the prosody measures examined here. Within the schizotypy group, increased prosodic expression was associated with positive schizotypy traits while decreased prosodic expression was associated with negative schizotypy traits. Prosodic deficits were significantly associated with reduced prosocial behaviors (e.g., talking with friends) but were not associated with subjective social satisfaction. Prosodic deficits characterize a subset of individuals with schizotypy who show a schizoid-like reduction in social behaviors without a concomitant reduction in social satisfaction.

Relationships between autistic-like and schizotypy traits: An analysis using the Autism Spectrum Quotient and Oxford-Liverpool Inventory of Feelings and Experiences

To further investigate claims of a relationship between autism and schizophrenia, the current study examined the associations between specific dimensions of autistic-like and schizotypy traits. These traits were assessed using the Autism Spectrum Quotient and the Oxford-Liverpool Inventory of Feelings and Experiences. After using factor analysis to explore the dimensions of autistic-like and schizotypy traits represented in these measures in two separate groups of students ( N 1 = 362, N 2 = 639), the relationships between these dimensions were examined. While the results are consistent with suggestions in the literature of an overlap in the interpersonal deficits associated with autism and schizophrenia, they offer little support for Crespi and Badcock’s (2008) claim that autism and positive schizophrenia are diametrically opposed disorders.

Premorbid Personality and Insight in First-Episode Psychosis

Insight in psychosis and schizophrenia is considered a complex biopsychosocial phenomenon. Premorbid personality is regarded by some authors as part of the substrate to many psychiatric phenomena, but it is not clear if this applies to insight. To examine longitudinal relationships between personality traits and insight dimensions in first-episode psychosis. One hundred consecutive antipsychotic-naïve first-episode nonaffective psychotic patients admitted to hospital were included in the study. Eighty-one patients completed at 1 month a premorbid personality evaluation, plus baseline, and 6-month insight assessments. We used the Assessment and Documentation of Psychopathology inventory for assessing insight dimensions (not feeling ill, lack of insight, and refusal of treatment) and the Personality Assessment Schedule for ascertaining 5 dimensions of premorbid personality (schizoid, passive-dependent, anancastic, sociopathic, and schizotypy). At baseline, personality dimensions did not show any association with insight dimensions, with the exception of schizotypy traits. At 6 months, schizoid and sociopathic personality showed a significant association with not feeling ill (r = .30, P ≤ .007; r = .27, P = .01) and lack of insight (r = .36, P = .001; r = .41, P < .001), respectively. When we calculated insight change, schizoid and sociopathic personality had moderate correlation with the lack of insight dimension (r = -.34, P = .002; r = .38, P < .001, respectively). After applying partial correlations for potential confounders and Bonferroni correction, the associations remained significant. Moreover, using a regression model, sociopathic and schizoid personality significantly predicted lack of insight at 6 months and change from baseline to the 6 months assessment. Sociopathic and schizoid personality dimensions were not only significantly associated with lack of insight at 6 months but also predicted change on lack of insight over 6 months. Therefore, exploring premorbid personality traits at the beginning of a psychotic episode may be helpful in identifying patients at high risk for lack of insight during the initial course of the illness.

Cannabis and psychometrically-defined schizotypy: Use, problems and treatment considerations

Cannabis use is associated with onset of psychosis in individuals vulnerable for developing schizophrenia-spectrum disorders. The present study addressed three knowledge gaps pertaining to this issue: 1) clarifying the incidence of cannabis use in schizotypal individuals, 2) examining how cannabis use is related to psychosocial and physiological problems in schizotypy and interest in treatment, and 3) examining how cannabis use is associated with positive, negative and disorganization features of schizotypy. Scores from a measure of schizotypal traits were used to trichotomize 1665 young adults into schizotypy (top 5% of scorers), non-schizotypy (bottom 50% of scorers) and “unconventional” (scorers within the 50th to 85th percentile) groups. Nearly a quarter of the schizotypy group endorsed cannabis use at least weekly, a rate nearly two to four times that of the other groups. The schizotypy group also reported a much greater frequency of cannabis-related problems compared to the other groups. Despite this, interest in treatment for cannabis use in the schizotypy group was not elevated. Interestingly, 85% of individuals in the schizotypy group reported interest in psychological/psychiatric treatment more generally. Cannabis use was not associated with abnormal patterns of positive or disorganized schizotypy traits in the schizotypy group relative to the other groups. However, cannabis use was associated with lower severity of negative traits. Implications of these results are discussed.

Left but not right hemisphere semantic processing abnormalities in language comprehension in subjects with schizotypy traits

Thought and language disorders in schizophrenia and schizotypy are thought to result from hemispheric dysfunction during semantic processing. Left hemisphere (LH) abnormalities are well established, but little is known about right hemisphere (RH) semantic processes. We explored hemispheric processing in 50 healthy volunteers assigned to high (h-SZT) or low schizotypy (l-SZT) group using the Schizotypal Personality Questionnaire (SPQ). Subjects were asked to make semantic judgments on sentence pair ending with a target that was either expected word (EW) or an unexpected word from the same (related violation, RV) or a different category (unrelated violation, URV). Targets were presented in a dichotic manner to the left or right ear. Analyses of reaction times in the l-SZT group showed semantic compatibility effect (URV-EW) in the LH and semantic memory activation effect (RV-URV) as well as semantic compatibility effect in the RH. The h-SZT group showed semantic memory activation but no semantic compatibility effect in the LH, the RH pattern resembling that of the l-SZT group. The magnitude of the LH semantic compatibility effect was inversely correlated with SPQ total scores and SPQ Cognitive-perceptual factor. Thus, RH semantic processes are effective and there is a deficit in LH focused activation in schizotypy.

Religious attachment dimensions and schizotypal personality traits

This brief pilot study explored associations between religious attachment (RA) and schizotypy in a nonclinical Christian sample (N = 96). Participants responded to questionnaires assessing the above constructs, as well as adult attachment and neuroticism. Religious attachment accounted for 15.2% of the variance in cognitive schizotypy. Anxious religious attachment uniquely predicted cognitive schizotypy, while its effects on other schizotypy traits were accounted for by adult attachment effects. Schizotypy research may benefit from considering attachment relationships in the religious domain. Should our findings be extended and replicated, they may aid the development of interventions, tailored for specific religious populations, which could improve treatment outcomes for schizotypal or schizophrenic individuals.

Hyper-priming in cannabis users: A naturalistic study of the effects of cannabis on semantic memory function

Psychotic symptoms have theoretically been linked to semantic memory impairments in patients with schizophrenia. Little is known of the effects of cannabis, the world's most popular illicit drug, on semantic memory and whether they are linked to the psychotomimetic states elicited by the drug. Thirty-six cannabis users were tested whilst under the influence of cannabis. They were then tested again when not intoxicated and compared with 38 non-drug using controls. Semantic memory was assessed using a semantic priming task with a long and short stimulus onset asynchrony (SOA) to differentiate automatic and controlled processing. Under the influence of cannabis, users showed increases in both automatic semantic priming and schizotypal symptoms compared with controls. When abstinent, cannabis users exhibited hyper-priming at long SOAs. Cannabis users did not differ from controls in either trait schizotypy or state schizotypy when not intoxicated. Acute cannabis use increases schizotypyal symptoms and may increase automatic semantic priming in recreational users of this drug. When drug-free, cannabis users did not differ from controls in schizotypy but did show hyper-priming at the long SOA. The acute increase in automatic semantic priming may be one factor contributing to the psychotomimetic effects of cannabis.

Are the Autism and Positive Schizotypy Spectra Diametrically Opposed in Local Versus Global Processing?

Crespi and Badcock (2008) proposed that autism and psychosis represent two extremes on a cognitive spectrum with normality at its center. Their specific claim that autistic and positive schizophrenia traits contrastingly affect preference for local versus global processing was investigated by examining Embedded Figures Test performance in two groups of students separated on autistic-like traits but matched on positive schizotypy traits, and two groups separated on positive schizotypy traits but matched on autistic-like traits (n = 20 per group). Consistent with their theory, higher levels of autistic-like traits were associated with faster identification of hidden figures, whereas higher levels of positive schizotypy traits were associated with slower identification.

Acute and Chronic Effects of Ketamine on Semantic Priming

Acute administration of the N-methyl-D-aspartate receptor antagonist ketamine induces schizophrenia-like symptoms in healthy volunteers; furthermore, a window on ketamine's chronic effects is provided by regular recreational users. The current study utilized both acute ketamine administration in healthy volunteers and chronic ketamine abusers to investigate semantic processing, one of the key cognitive deficits in schizophrenia. Semantic processing was examined using a semantic priming paradigm. In experiment 1, acute effects of low (75 ng/mL) and high (150 ng/mL) ketamine doses were compared in a placebo-controlled double-blind independent group design with 48 participants. In experiment 2, 19 regular recreational ketamine users were compared with 19 ketamine-naive polydrug controls and 26 non-drug-using controls. In both experiments, semantic priming parameters were manipulated to distinguish between ketamine's effects on (1) automatic and strategic processing and (2) the facilitation and inhibition components of semantic priming for strongly (directly) related primes and targets. Acute effects of ketamine on semantic priming for weakly (indirectly) related primes and targets were also assessed in experiment 1. Acutely, ketamine impaired the employment of strategic mechanisms but not automatic processing within both the direct and indirect semantic priming tasks. Acute ketamine administration also induced clear schizophrenia-like symptoms. Schizotypy traits in the cognitive and perceptual domains tended to correlate with increased semantic priming in long-term ketamine users. In summary, acute and chronic ketamine-induced changes partially mirrored the findings on semantic priming in schizophrenia.

Schizotypal traits impact upon executive working memory and aspects of IQ

Previous inconsistent findings concerning a link between working memory dysfunction and negative aspects of non-clinical schizotypy have been interpreted to cast doubt on the continuity model of ‘negative psychosis-proneness’. This study employed the Letter-Number-Sequencing (LNS) task and the Trail-Making Test to assess more demanding, executive working memory. A secondary concern was to rule out possible mediating effects of familial schizophrenia. It was hypothesised that executive working memory impairment would be associated primarily with negative rather than positive schizotypy even in the absence of familial schizophrenia. Matrix reasoning controlled for IQ. In 87 university-student participants with no known family history of schizophrenia, lower LNS scores were associated with higher levels of negative and positive schizotypy traits. Counter to expectations, matrix reasoning scores were also associated with schizotypy, primarily the cognitive/perceptual traits. Results were similar when participants with a known family history of schizophrenia (10) were included ( N = 97). Findings support the view that impairment of executive working memory (indexed by LNS) is a reliable cognitive marker for negative (and perhaps also positive) schizophrenia vulnerability, independent of familial schizophrenia, and provide the first indication that some facets of IQ (e.g. inductive reasoning) might also be compromised in non-clinical schizotypy.

Highly schizotypal students have a weaker sense of self‐agency

Schizotypy can be seen as an indicator of a predisposition to schizophrenia. It is possible that schizotypal people have an abnormal self-consciousness, especially with regard to the sense of self-agency. Students were rated using the Schizotypy Traits Questionnaire (STA). They were asked to press a button, which generated a tone after some delay. They were then required to judge whether they felt they or someone else had generated the tone. The results showed that the high schizotypy group had a weaker sense of self-agency than the low schizotypy group. The present study used an experimental method to show that schizotypal traits are correlated with an abnormal sense of self-agency.

Smoking status affects men and women differently on schizotypal traits and cognitive failures

Men have a greater risk of schizophrenia than women, and are generally heavier smokers than women. Smoking has been viewed as a form of self-medication in both schizophrenia and schizotypy, to the degree that it helps control negative symptoms and enhance cognitive function. To identify how smoking affects men and women differently on schizotypal traits and cognitive failures, the effects of gender and smoking on schizotypy traits and cognitive failures were assessed in 613 undergraduate men and women (mean age = 19.0 years), using Schizotypal Personality Questionnaire (SPQ) and Cognitive Failures Questionnaire (CFQ). Participants were divided into non-smokers, daily smokers, and non-daily smokers. In general, men showed more Interpersonal and Disorganized Deficits (SPQ) and Names Lapses (CFQ; failure to recall a name), than women. Independent of gender, daily smoking was associated with greater Cognitive-Perceptual Deficits (SPQ) and more Names Lapses, and non-daily smoking was positively correlated with memory (CFQ). In addition, non-daily smoking was associated with increased Interpersonal Deficits in men but decreased scores on this scale in women. Support for the self-medication model of smoking was found among daily smoking, but the relationship among non-daily smoking, schizotypy, cognitive failures, and gender was complex, bearing closer scrutiny in future research.

Psychological functioning and health‐related quality of life in adulthood after preterm birth

The aim of this study was to determine if preterm birth is associated with socioeconomic status (SES), psychological functioning, and health-related quality of life (HRQoL) in adulthood. We used prospective follow-up of 192 adult offspring of mothers who took part in a randomized controlled trial of antenatal betamethasone for the prevention of neonatal respiratory distress syndrome (66 born at term [33 males, 33 females] 126 born preterm [66 males, 60 females]). Cognitive functioning was assessed using the Wechsler Abbreviated Scale of Intelligence. Working memory and attention was assessed using the Benton Visual Retention Test, the Paced Auditory Serial Addition Test, and the Brown Attention Deficit Disorder Scale. Psychiatric morbidity was assessed using the Beck Depression Inventory II, the State-Trait Anxiety Inventory, and the Schizotypy Traits Questionnaire. Handedness was assessed using the Edinburgh Handedness Inventory. HRQoL was assessed using the Short Form-36 Health Survey. Moderately preterm birth (median gestation 34wks, mean birthweight 1946g [SD 463g]) was not related to later marital status, educational attainment, SES, cognitive functioning, working memory, attention, or symptoms of anxiety or schizotypy at 31 years of age. Preterm birth was associated with fewer symptoms of depression and higher levels of satisfaction in three of the eight HRQoL domains measured (bodily pain, general health perception, and social functioning). Adults who were born moderately preterm have SES, psychological functioning, and HRQoL consistent with those who were born at term. This good long-term outcome cannot be extrapolated to those with early childhood disability or very low birthweights.