Schizotypy Scores Research Articles

Additive Effects of Former Methylenedioxymethamphetamine and Cannabis Use on Subclinical Psychotic Symptoms.

Methylenedioxymethamphetamine (MDMA) is an amphetamine-derived psychostimulant, usually known as "ecstasy." The long-term neuropsychological effects of MDMA are examined in several studies with conflicting results. The most common findings reported are depression, anxiety, and memory and attention deficits. In addition to acute psychotic reactions observed after MDMA use, serotonergic and dopaminergic toxicities may increase the psychosis risk in the long-term. Cannabis usage among MDMA users is very high. The aim of this study was, therefore, to examine the additive effects of cannabis and MDMA on subclinical psychotic symptoms (SPS). Here, 131 healthy controls (hC), 54 former cannabis and MDMA users (C&M), and 46 former cannabis users (C) were evaluated for SPS. The definition of former user was based on the Munich Composite International Diagnostic Interview. The SPS scores were assessed by using the Schizotypal Personality Questionnaire (SPQ). The relationship between substance-free periods and total MDMA exposure with SPS was also examined. The C&M group had higher levels of SPS than both C and hC groups. This is true not only for the total SPQ scores but both positive and negative schizotypy scores as well as cognitive-perceptual, disorganized, and interpersonal schizotypy scores aligned hierarchically in the 3 study groups (C&M>C>hC). The total MDMA exposure was positively correlated and MDMA-free period was negatively correlated with the SPS score. We found that the former use of cannabis and MDMA is associated with marked elevation in SPS. Moreover, the exposure amount of MDMA and MDMA-free periods are important determinants of SPS. The longer the cannabis and ecstasy free periods, the larger is the waning of SPS.

Increased distractibility in schizotypy: Independent of individual differences in working memory capacity?

Individuals with schizophrenia typically show increased levels of distractibility. This has been attributed to impaired working memory capacity (WMC), since lower WMC is typically associated with higher distractibility, and schizophrenia is typically associated with impoverished WMC. Here, participants performed verbal and spatial serial recall tasks that were accompanied by to-be-ignored speech tokens. For the few trials wherein one speech token was replaced with a different token, impairment was produced to task scores (a deviation effect). Participants subsequently completed a schizotypy questionnaire and a WMC measure. Higher schizotypy scores were associated with lower WMC (as measured with operation span, OSPAN), but WMC and schizotypy scores explained unique variance in relation to the mean magnitude of the deviation effect. These results suggest that schizotypy is associated with heightened domain-general distractibility, but that this is independent of its relationship with WMC.

T66 - The Neuregulin-1 Gene Is Associated With Schizotypy In The General Population

Background It is believed that the personality characteristics and symptoms observed in schizophrenia lie on a continuum, with subclinical symptoms referred to as schizotypy. The continuum theory of schizophrenia recognises schizotypy as a suitable model for investigating schizophrenia: individuals with high levels of schizotypy demonstrate similar symptoms, cognitive profiles and neuroimaging findings to schizophrenia, albeit in a more subtle manner, without the potential confounding factors associated with schizophrenia. Both schizophrenia and schizotypy have been shown to be influenced by genetic factors. Neuregulin-1 (NRG1), involved in neuronal development, migration, myelination and synaptic plasticity, has been identified as a promising candidate gene for schizophrenia risk. Several NRG1 single nucleotide polymorphisms (SNPs) have been associated with schizophrenia and cognitive deficits, though only one SNP has been previously associated with schizotypy. The aim of this study was to examine the link between NRG1 and schizotypy across the schizotypy/schizophrenia continuum. Methods Participants were 200 adults (83 patients with schizophrenia and 117 healthy controls) who were assessed for schizotypy factors using the Oxford-Liverpool Inventory of Feelings and Experience (O-LIFE). The factors assessed were unusual experiences (UnEx), introvertive anhedonia (InAn) and cognitive disorganisation (CogDis), which are thought to reflect the positive, negative and cognitive symptoms of schizophrenia respectively. Participants were also genotyped for five NRG1 SNPs; rs10503929, rs3924999, rs2466058, rs35753505 and rs6994992. A MANOVA was conducted with schizotypy factors as dependent variables and participant group as independent variables to observe differences between patients and controls. Another MANOVA was conducted with schizotypy factors as dependent variables and NRG1 SNPs as independent variables to observe differences and interactions of the NRG1 SNPs on schizotypy across the continuum. Results Confirming previous findings, schizotypy scores were significantly higher in the patient group as compared to controls (p Discussion This is the first study to demonstrate an association between NRG1 and schizotypy across the continuum, in particular CogDis. From this, it can be inferred that genetic variation in NRG1 may be a contributing factor to cognitive deficits in the clinical population, consistent with previous findings. As individual SNPs were not significantly associated with schizotypy but significant interactions were observed, this study also demonstrates the heterogeneity of schizophrenia. This finding contributes to the literature associating NRG1 with cognitive deficits in schizophrenia and supports the use of schizotypy as a model for schizophrenia.

Overshadowing depends on cue and reinforcement sensitivity but not schizotypy

There is evidence for impaired selective learning mechanisms in individuals high in schizotypy. Overshadowing provides a direct test of selective learning based on cue salience and has previously been reported to be impaired in relation to schizotypy scores. The present study tested for overshadowing using food allergy and Lego construction task variants. Both variants used the same number of conditioned stimulus (CS) cues and the same number of learning trials. CS cues were trained in compound pairs or in isolation and overshadowing was subsequently tested on trials followed by negative versus positive outcomes. Participants also completed the O-LIFE to measure schizotypy and BIS-BAS scales to measure reinforcement sensitivity. Learning was demonstrated for both cue variants; however overshadowing emerged only in the Lego variant and only on the trials followed by the negative outcome. Contrary to expectations, there was no evidence for any relationship between overshadowing and O-LIFE scores. However, there was evidence of a positive relationship between overshadowing and BAS-Drive as well as a negative relationship with BIS-Anxiety, for the trials followed by the positive outcome in the food allergy variant. These results suggest that the development of overshadowing depends on cue and reinforcement sensitivity, but not necessarily on schizotypy.

Familial aggregation of schizotypy in schizophrenia-spectrum disorders and its relation to clinical and neurodevelopmental characteristics

IntroductionThis study explored schizotypy as a familial liability marker for schizophrenia-spectrum disorders (SSD) by examining: 1) the aggregation of schizotypy in families with a SSD patient, 2) whether familial resemblance of schizotypy is associated with ridge dissociations (RD), another SSD liability marker, 3) whether schizotypy aggregation patterns influence patients' psychopathology. MethodsThe sample comprised 30 SSD patients and 82 healthy first-degree relatives. Schizotypy was assessed using the Structured Interview for Schizotypy-Revised (SIS-R). Patients' psychopathology was evaluated using the Comprehensive Assessment of Symptoms and History (CASH). RD were identified as anomalies of the dermal ridge junction. Familiality of SIS-R was investigated using a linear mixed model (LMM) and its strength was assessed using an intraclass correlation coefficient (ICC). Another LMM using the absolute differences in SIS-R scores between all possible pairs of relatives as the dependent variable was fitted to obtain an intra-family resemblance score, a family-specific indicator of resemblance of SIS-R scores within each family. Results1) Schizotypy was familial (ICC = 0.30); families with high resemblance displayed low schizotypy, whereas families with low resemblance included at least one healthy relative with high schizotypy (p < 0.001). 2) Relatives with RD had higher SIS-R scores (p = 0.018) and belonged to families with discordant schizotypy scores among members (p < 0.001). 3) Patients from high schizotypy families showed more severe disorganized symptoms at the psychotic episode (p = 0.035) and 1 year later (p = 0.011). ConclusionsSchizotypy is a marker of vulnerability for SSD that runs within a subgroup of families. The schizotypy familial aggregation pattern correlates with RD in relatives and with patients' psychopathology.

Examining lexical processing with two word tasks using the schizotypy analogue.

Semantic processing is impaired in schizophrenia, and is often assessed using word-based semantic tasks that additionally require lexical processing for accurate performance. This study aimed to examine lexical processing in relation to psychosis proneness. 61 individuals (mean age=22.92, SD=2.67) completed a schizotypy questionnaire and two lexical processing tasks (recognition and production). Results revealed no relationship between increasing schizotypy scores and overall performance on either lexical processing task. Lexical processing performance is not related to psychosis-proneness. This is discussed in relation to schizophrenia semantic processing research.

Analyse de la structure factorielle de la version brève du questionnaire de personnalité schizotypique (SPQ-B) – format Likert – en population générale en France

IntroductionThe main objective of the study was to explore the factorial structure of the French version of the Schizotypal Personality Questionnaire-Brief (SPQ-B) in a Likert format, in a representative sample of the general population. In addition, differences in the dimensional scores of schizotypy according to gender and age were analyzed. As the study in the general population of schizotypal traits and its determinants has been recently proposed as a way toward the understanding of aetiology and pathophysiology of schizophrenia, consistent self-report tools are crucial to measure psychometric schizotypy. A shorter version of the widely used Schizotypal Personality Questionnaire (SPQ-Brief) has been extensively investigated in different countries, particularly in samples of students or clinical adolescents, and more recently, a few studies used a Likert-type scale format which allows partial endorsement of items and reduces the risk of defensive answers. MethodA sample of 233 subjects representative of the adult population from an urban area near Paris (Créteil) was recruited using the “itinerary method”. They completed the French version of the SPQ-B with a 5-point Likert-type response format (1=completely disagree; 5=completely agree). We examined the dimensional structure of the French version of the SPQ-B with a Principal Components Analysis (PCA) followed by a promax rotation. Factor selection was based on Eigenvalues over 1.0 (Kaiser's criterion), Cattell's Scree-plot test, and interpretability of the factors. Items with loadings greater than 0.4 were retained for each dimension. The internal consistency estimate of the dimensions was calculated with Cronbach's α. In order to study the influence of age and gender, we carried out a simple linear regression with the subscales as dependent variables. ResultsOur sample was composed of 131 women (mean age=52.5±18.2 years) and 102 men (mean age=53±18.1 years). SPQ-B Likert total scores ranged from 22 to 84 points (mean=43.6±13). Factor analysis resulted in a 3-factor solution that explained 47.7% of the variance. Factor 1 (disorganized; 10 items) included items related to “odd behavior”, “odd speech”, as well as “social anxiety”, one item of “constricted affect” and one item of “ideas of reference”. Factor 2 (interpersonal; 7 items) included items related to “no close friends”, “constricted affect”, and three of the items of “suspiciousness”. Factor 3 (cognitive-perceptual; 5 items) included items related to “ideas of reference”, “magical thinking”, “unusual perceptual experiences” and one item of “suspiciousness”. Coefficient α for the three subscales and total scale were respectively 0.81, 0.81, 0.77 and 0.88. We found no differences in total schizotypy and the three dimensions scores according to age and sex. ConclusionFactor analysis of the French version of the SPQ-B in a Likert format confirmed the three-factor structure of schizotypy. We found a pure cognitive perceptual dimension including the most representative positive features. As expected, “Suspiciousness” subscale is included in both positive and negative dimensions, but mainly in the negative dimension. Surprisingly, “social anxiety” subscale is included in the disorganized dimension in our analysis. The SPQ-B in a Likert format demonstrated good internal reliability for both total and subscales scores. Unlike previous published results, we did not find any influence of age or gender on schizotypal dimensions.

Musical minds: Personality, schizotypy, and involuntary musical imagery.

Musical imagery-hearing music in your mind that isn't playing in the environment-is a common experience (Williams, 2015). Research has sought to describe what it is like and how often it happens, with emphasis on involuntary musical imagery (INMI), sometimes referred to as earworms. Liikkanen (2012) found that about 90% of people experience INMI at least once a week and typically hear songs they are familiar with; other researchers have found similar results with INMI (Floridou & Mullensiefen, 2015; Halpern & Bartlett, 2011; Hyman et al., 2015) and musical imagery more broadly (Bailes, 2006; Beaty et al., 2013). In addition, research has found that people generally consider these to be positive experiences (Bailes, 2007; Beaman & Williams, 2010; Beaty et al., 2013; Floridou & Mullensiefen, 2015; Halpern & Bartlett, 2011; Hyman et al., 2015).Although most research has examined what INMI and general musical imagery experiences are like, the present research focuses on INMI and how different aspects of these experiences relate to personality and schizotypy. To date, only a handful of studies have considered the role of personality traits in the experience of INMI and musical imagery more generally. Beaty et al. (2013) examined the Big 5 personality traits and general musical imagery using both experience sampling measures and retrospective surveys. In both cases, openness to experience-and, to a lesser extent, neuroticism- were related to how often people heard inner music. Similarly, Kellaris (2001) found that people higher in neuroticism experience INMI more frequently. These studies, however, did not examine how personality relates to different aspects of INMI experiences. Floridou, Williamson, and Mullensiefen (2012) found that, of the Big 5 personality traits, neuroticism and openness to experience were related to different aspects of INMI. Specifically, people high in neuroticism had longer episodes of INMI, found them more worrying, felt they were interfering with daily activities, and saw these experiences as more unpleasant; people higher in openness had longer episodes and felt their INMI interfered with their daily activities. From this small collection of studies, it appears that openness to experience and neuroticism relate to both INMI and general musical imagery experiences.Additionally, some research has examined how INMI is associated with general mental control abilities and schizotypy. Schizotypy is a construct that represents the continuum of risk, from normal to clinical, for schizophrenia and related disorders (Kwapil, Barrantes-Vidal, & Silvia, 2008). Schizotypal experiences commonly sort into two broad factors: positive symptoms associated with deviant beliefs and experiences, and negative symptoms associated with diminished pleasure and motivation (Kwapil, Gross, Silvia, & Barrantes-Vidal, 2013). Mental slippage-low cognitive control-is a defining deficit in people with schizophrenia (Wongupparaj, Kumari, & Morris, 2015), and it is apparent in less severe forms in people with elevated schizotypy scores. Lower control in schizotypy is associated with reduced filtering of auditory stimuli as well as aberrant sensory experiences (Croft, Lee, Bertolot, & Gruzelier, 2001; Ettinger et al., 2015). This suggests that people high in schizotypy are more likely to experience involuntary imagery-specifically auditory imagery (Ettinger et al., 2015; Gray, Snowden, Peoples, Hemsley, & Gray, 2003; Lagioia, Van De Ville, Debbane, Lazeyras, & Eliez, 2010).Beaman and Williams (2013) explored the roles of mental control, using the White Bear Suppression Inventory (Wegner & Zanakos, 1994), and schizotypy (Raine, 1991). Raine's (1991) measure of schizotypy consists of three factors-Cognitive-Perceptual (unusual perceptual experiences and magical thinking), Interpersonal (social anxiety, constriction of affect), and Disorganized (odd behaviors and speech). Lower mental control was associated with difficulty in stopping earworms; both lower mental control and higher schizotypy- particularly the cognitive-perceptual factor-were associated with feeling that the earworm was disrupting daily activities and the selfreported duration of the earworms (Beaman & Williams, 2013). …

Handedness and schizotypy: The potential effect of changing the writing-hand

Mixed-handedness, which has been associated with schizotypy in recent studies, might exist for at least two different reasons: it is innate or it has been forced. We examined whether the association between mixed-handedness and schizotypy differs depending on its source. We enrolled 3485 college students in Taiwan. We used both the Perceptual Aberration Scale and Schizotypal Personality Questionnaire to assess schizotypy, and the Annett Hand Preference Questionnaire to assess handedness. Two ways of classifying handedness were examined: the three-way classification based on Annett's categories and mixed- vs. non-mixed-handedness based on Degree of Handedness. Both mixed-handedness groups showed higher positive schizotypy scores. Among mixed handers, those who had been required to change their writing hand from left to right had higher positive schizotypy scores. Being forced to change writing hand seemed to be related to a higher level of schizotypy. The potential effect of the social pressure against using the left hand for writing is discussed.

Schizotypy and mindfulness: Magical thinking without suspiciousness characterizes mindfulness meditators

Despite growing evidence for demonstrated efficacy of mindfulness in various disorders, there is a continuous concern about the relationship between mindfulness practice and psychosis. As schizotypy is part of the psychosis spectrum, we examined the relationship between long-term mindfulness practice and schizotypy in two independent studies. Study 1 included 24 experienced mindfulness practitioners (19 males) from the Buddhist tradition (meditators) and 24 meditation-naïve individuals (all males). Study 2 consisted of 28 meditators and 28 meditation-naïve individuals (all males). All participants completed the Schizotypal Personality Questionnaire (Raine, 1991), a self-report scale containing 9 subscales (ideas of reference, excessive social anxiety, magical thinking, unusual perceptual experiences, odd/eccentric behavior, no close friends, odd speech, constricted affect, suspiciousness). Participants of study 2 also completed the Five-Facet Mindfulness Questionnaire which assesses observing (Observe), describing (Describe), acting with awareness (Awareness), non-judging of (Non-judgment) and non-reactivity to inner experience (Non-reactivity) facets of trait mindfulness. In both studies, meditators scored significantly lower on suspiciousness and higher on magical thinking compared to meditation-naïve individuals and showed a trend towards lower scores on excessive social anxiety. Excessive social anxiety correlated negatively with Awareness and Non-judgment; and suspiciousness with Awareness, Non-judgment and Non-reactivity facets across both groups. The two groups did not differ in their total schizotypy score. We conclude that mindfulness practice is not associated with an overall increase in schizotypal traits. Instead, the pattern suggests that mindfulness meditation, particularly with an emphasis on the Awareness, Non-judgment and Non-reactivity aspects, may help to reduce suspiciousness and excessive social anxiety.

Cognitive and oculomotor performance in subjects with low and high schizotypy: implications for translational drug development studies.

The development of drugs to improve cognition in patients with schizophrenia is a major unmet clinical need. A number of promising compounds failed in recent clinical trials, a pattern linked to poor translation between preclinical and clinical stages of drug development. Seeking proof of efficacy in early Phase 1 studies in surrogate patient populations (for example, high schizotypy individuals where subtle cognitive impairment is present) has been suggested as a strategy to reduce attrition in the later stages of drug development. However, there is little agreement regarding the pattern of distribution of schizotypal features in the general population, creating uncertainty regarding the optimal control group that should be included in prospective trials. We aimed to address this question by comparing the performance of groups derived from the general population with low, average and high schizotypy scores over a range of cognitive and oculomotor tasks. We found that tasks dependent on frontal inhibitory mechanisms (N-Back working memory and anti-saccade oculomotor tasks), as well as a smooth-pursuit oculomotor task were sensitive to differences in the schizotypy phenotype. In these tasks the cognitive performance of ‘low schizotypes' was significantly different from ‘high schizotypes' with ‘average schizotypes' having an intermediate performance. These results indicate that for evaluating putative cognition enhancers for treating schizophrenia in early-drug development studies the maximum schizotypy effect would be achieved using a design that compares low and high schizotypes.

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

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

Schizotypy and awareness of intention: Variability of W judgments predicts schizotypy scores.

Abstract Patients with schizophrenia often have unusual experiences of action. For example, patients suffering from delusions of control feel that their voluntary actions are under the control of an external force. It has been argued that deficits in self-monitoring are responsible for these symptoms. However, to-date the self-monitoring of intention has been overlooked in studies on schizophrenia. Here we aim to address this oversight. We carried out a preliminary investigation of possible intention monitoring issues in schizophrenia by examining the relation between the awareness of intention and schizotypy in a healthy population. Using the Libet clock task we found that the variability of intention (or W) judgments was uniquely predictive of schizotypy: the more variable these judgments the higher the schizotypy score. We discuss the relevance of the findings for schizophrenic illness. We also discuss the utility of this intention variability measure for examining volitional disturbances more generally.

Brain structural correlates of schizotypy and psychosis proneness in a non-clinical healthy volunteer sample

Schizotypal traits are phenotypic risk factors for schizophrenia, associated with biological changes across a putative schizophrenia spectrum. In this study, we tested the hypothesis that brain structural changes in key brain areas relevant to this spectrum (esp. medial and lateral prefrontal cortex) would vary across different degrees of schizotypal trait expression and/or phenotypic markers of psychosis proneness in healthy non-clinical volunteers. We analysed high-resolution 3Tesla magnetic resonance images (MRI) of 59 healthy volunteers using voxel-based morphometry (VBM), correlating grey matter values to the positive and negative symptom factors of the schizotypal personality questionnaire (SPQ, German version) and a measure of psychosis proneness (community assessment of psychic experiences, CAPE). We found positive correlations between positive SPQ dimension and bilateral inferior and right superior frontal cortices, and positive CAPE dimension and left inferior frontal cortex, as well as CAPE negative dimension and right supplementary motor area (SMA) and left inferior parietal cortex. However, only the positive correlation of the right precuneus with negative schizotypy scores was significant after FWE correction for multiple comparisons. Our findings confirm an effect of schizotypal traits and psychosis proneness on brain structure in healthy subjects, providing further support to a biological continuum model.

Pituitary volume and clinical trajectory in young relatives at risk for schizophrenia

Stress and vulnerability likely interact to play a major role in psychosis. While much has been written about the neural diathesis-stress model in psychosis and its clinical risk states, little is known about HPA axis biomarkers in non-help-seeking individuals at familial high risk (FHR). We sought to prospectively measure pituitary volume (PV) in adolescents and young adults at FHR for schizophrenia and to follow their emerging sub-clinical psychotic symptoms and clinical trajectories. Forty healthy controls and 38 relatives of patients with schizophrenia or schizoaffective disorder were identified in Pittsburgh, USA. PV was derived from baseline 1.5 T magnetic resonance imaging. Chapman's schizotypy scales were acquired at baseline, and structured clinical interviews for DSM-IV-TR Axis I diagnoses were attempted annually for up to 3 years. Seven individuals converted to psychosis. PV did not differ between FHR and control groups overall. Within the FHR group, PV was positively correlated with Chapman's positive schizotypy (Magical Ideation and Perceptual Aberration) scores, and there was a significant group × PV interaction with schizotypy. PV was significantly higher in FHR subjects carrying any baseline Axis I diagnosis (p = 0.004), and higher still in individuals who went on to convert to psychosis (p = 0.0007). Increased PV is a correlate of early positive schizotypy, and may predict trait vulnerability to subsequent psychosis in FHR relatives. These preliminary findings support a model of stress-vulnerability and HPA axis activation in the early phases of psychosis.

Assessment of self-disorders in a non-clinical population: Reliability and association with schizotypy

This study explores whether self-disorders occur and can be assessed reliably in a non-clinical sample, and whether the prevalence of these anomalies depends upon the degree of psychometrically defined schizotypy. Participants with either high (n=30) or low (n=20) schizotypy scores were interviewed using a modified version of the Examination of Anomalous Self-Experience (EASE). The degree to which interviewees experienced self-disorder symptoms was rated by the interviewer and an independent rater. Inter-rater reliability was calculated for each item, domain scores and the total score. For the total, sample most items (=66) showed substantial or perfect agreement (κ>0.61), with a few (=6) showing moderate agreement (κ>0.41). Reliability scores were only slightly lower when just the more homogeneous group of individuals with high Schizotypal Personality Questionnaire (SPQ) scores were examined. As expected, high SPQ scores were associated with a high level of self-disorders. In sum, the results suggest that self-disorders can be measured reliably in non-clinical samples and are particularly frequent in individuals with pronounced schizotypical traits.

Failure of deactivation in the default mode network: a trait marker for schizophrenia?

Functional imaging studies in relatives of schizophrenic patients have had inconsistent findings, particularly with respect to altered dorsolateral prefrontal cortex activation. Some recent studies have also suggested that failure of deactivation may be seen. A total of 28 patients with schizophrenia, 28 of their siblings and 56 healthy controls underwent functional magnetic resonance imaging during performance of the n-back working memory task. An analysis of variance was fitted to individual whole-brain maps from each set of patient-relative-matched pair of controls. Clusters of significant difference among the groups were then used as regions of interest to compare mean activations and deactivations among the groups. In all, five clusters of significant differences were found. The schizophrenic patients, but not the relatives, showed reduced activation compared with the controls in the lateral frontal cortex bilaterally, the left basal ganglia and the cerebellum. In contrast, both the patients and the relatives showed significant failure of deactivation compared with the healthy controls in the medial frontal cortex, with the relatives also showing less failure than the patients. Failure of deactivation was not associated with schizotypy scores or presence of psychotic-like experiences in the relatives. Both schizophrenic patients and their relatives show altered task-related deactivation in the medial frontal cortex. This in turn suggests that default mode network dysfunction may function as a trait marker for schizophrenia.

Prefronto-striatal physiology is associated with schizotypy and is modulated by a functional variant of DRD2.

“Schizotypy” is a latent organization of personality related to the genetic risk for schizophrenia. Some evidence suggests that schizophrenia and schizotypy share some biological features, including a link to dopaminergic D2 receptor signaling. A polymorphism in the D2 gene (DRD2 rs1076560, guanine > thymine (G > T)) has been associated with the D2 short/long isoform expression ratio, as well as striatal dopamine signaling and prefrontal cortical activity during different cognitive operations, which are measures that are altered in patients with schizophrenia. Our aim is to determine the association of schizotypy scores with the DRD2 rs1076560 genotype in healthy individuals and their interaction with prefrontal activity during attention and D2 striatal signaling. A total of 83 healthy subjects were genotyped for DRD2 rs1076560 and completed the Schizotypal Personality Questionnaire (SPQ). Twenty-six participants underwent SPECT with [123I]IBZM D2 receptor radiotracer, while 68 performed an attentional control task during fMRI. We found that rs1076560 GT subjects had greater SPQ scores than GG individuals. Moreover, the interaction between schizotypy and the GT genotype predicted prefrontal activity and related attentional behavior, as well as striatal binding of IBZM. No interaction was found in GG individuals. These results suggest that rs1076560 GT healthy individuals are prone to higher levels of schizotypy, and that the interaction between rs1076560 and schizotypy scores modulates phenotypes related to the pathophysiology of schizophrenia, such as prefrontal activity and striatal dopamine signaling. These results provide systems-level qualitative evidence for mapping the construct of schizotypy in healthy individuals onto the schizophrenia continuum.

Autistic-like and schizotypal traits in a life history perspective: diametrical associations with impulsivity, sensation seeking, and sociosexual behavior

According to recent theoretical models, autistic-like and schizotypal traits can be regarded as opposite sides of a single continuum of variation in personality and cognition, and may be diametrically associated with individual differences in life history strategies. In this view, schizotypy is a psychological phenotype oriented toward high mating effort and reduced parenting, consistent with a fast life history strategy, whereas autistic-like traits contribute to a slow strategy characterized by reduced mating effort and high parental investment. In this study, we tested the hypothesis that autistic-like and schizotypal traits would be diametrically associated with unrestricted sociosexuality, impulsivity, and sensation seeking (three key behavioral correlates of fast life history strategies in humans) in a sample of 152 young adults (18–38 years). The results were consistent with a diametrical autism–schizotypy axis of individual variation. In line with our hypotheses, autism–schizotypy scores were uniquely associated with individual differences in impulsivity, sensation seeking, and sociosexual behavior, even after controlling for variation in Big Five personality traits. However, we found no significant associations with sociosexual attitude in the present sample. Our findings provide additional support for a life history model of autistic-like and schizotypal traits and demonstrate the heuristic value of this approach in the study of personality and psychopathology.

Extreme Elemental Processing in a High Schizotypy Population: Relation to Cognitive Deficits

The cognitive deficits observed in schizophrenia have been characterized as a failure to utilize task-setting information to guide behaviour, especially in situations in which there is response conflict. Recently, we have provided support for this account; high schizotypy individuals demonstrated inferior biconditional discrimination performance compared to low scorers, but were not impaired on a simple discrimination that did not require the use of task-setting cues. These results may, however, also be explained by the way in which individuals with high schizotypy process stimulus compounds. Here, we examine the initial approaches to solving biconditional and control discrimination tasks of participants with high and low schizotypy scores. In particular, we focus on performance during the first block of training trials to capture processing style before the acquisition of the discrimination tasks. Participants scoring highly on the introvertive anhedonia subscale (which has been allied to the negative and cognitive symptoms of schizophrenia) demonstrated better biconditional performance during the first block of training trials than did low-schizotypy individuals, consistent with a highly elemental approach to stimulus processing. Subsequent recognition tests confirmed this analysis demonstrating that the pattern of performance observed in participants with high schizotypy was associated with a failure to discriminate conjunctions of items that had been seen before from those that had not. These results suggest that the negative/cognitive symptoms of schizophrenia may reflect an extreme bias towards elemental, as opposed to configural, processing of stimulus conjunctions.