Thought disorder, perceptual aberrations, and schizotypy

Disembodiment and Language in Schizophrenia: An Integrated Psychopathological and Evolutionary Perspective

Different hypotheses have flourished to explain the evolutionary paradox of schizophrenia. In this contribution, we sought to illustrate how, in the schizophrenia spectrum, the concept of embodiment may underpin the phylogenetic and developmental pathways linking sensorimotor processes, the origin of human language, and the construction of a basic sense of the self. In particular, according to an embodied model of language, we suggest that the reuse of basic sensorimotor loops for language, while enabling the development of fully symbolic thought, has pushed the human brain close to the threshold of a severe disruption of self-embodiment processes, which are at the core of schizophrenia psychopathology. We adopted an inter-disciplinary approach (psychopathology, neuroscience, developmental biology) within an evolutionary framework, to gain an integrated, multi-perspectival model on the origin of schizophrenia vulnerability. A maladaptive over-expression of evolutionary-developmental trajectories toward language at the expense of embodiment processes would have led to the evolutionary "trade-off" of a hyper-symbolic activity to the detriment of a disembodied self. Therefore, schizophrenia psychopathology might be the cost of long-term co-evolutive interactions between brain and language.

Cognitive correlates of 'Formal Thought Disorder' in a non-clinical sample with elevated schizotypal traits

Different dimensions of formal thought disorder (FTD) are distinguished by different patterns of cognitive dysfunction in patients with schizophrenia; however, inconsistent findings may relate to patient-related confounds. To avoid these confounds, we examined relationships between FTD dimensions and cognitive domains in a non-clinical sample with attenuated schizophrenia-like traits, or schizotypal traits, on the Schizotypal Personality Questionnaire (N = 91). To our knowledge, no study has done this. FTD dimension scores were derived following principal component analysis of the Scale for the Assessment of Thought, Language and Communication (TLC dimensions: Disorganisation, Verbosity, Emptiness) and the Thought and Language Index (TLI dimensions: Negative, Idiosyncratic). The sample completed a comprehensive neuropsychological battery. Findings indicate that higher-order reasoning, executive function (set shift and generative ability) and language/semantic functioning are the primary drivers of FTD in our non-clinical sample with elevated schizotypal traits, in line with schizophrenia research. FTD may have shared aetiology along the schizophrenia spectrum.

Mild-to-moderate schizotypal traits relate to physiological arousal from social stress

Schizotypy denotes psychosis-like experiences, such as perceptual aberration, magical ideation, and social anxiety. Altered physiological arousal from social stress is found in people with high schizotypal traits. Two experiments aimed to determine the relationship of schizotypy to physiological arousal from social stress. Experiment 1 tested the hypotheses that heart rate from social stress would be greater in high, than mild-to-moderate, schizotypal traits, and disorganized schizotypy would explain this effect because of distress from disorganisation. Experiment 1 tested social stress in 16 participants with high schizotypal traits and 10 participants with mild-to-moderate schizotypal traits. The social stress test consisted of a public speech and an informal discussion with strangers. The high schizotypal group had a higher heart rate than the mild-to-moderate schizotypal group during the informal discussion with strangers, but not during the public speech. Disorganized schizotypy accounted for this group difference. Experiment 2 tested the hypothesis that mild-to-moderate schizotypal traits would have a linear relationship with physiological arousal from social stress. Experiment 2 tested 24 participants with mild-to-moderate schizotypal traits performing the abovementioned social stress test while their heart rate and skin conductance responses were measured. Mild-to-moderate schizotypal traits had a linear relationship with physiological arousal during the discussion with strangers. Distress in disorganized schizotypy may explain the heightened arousal from close social interaction with strangers in high schizotypy than mild-to-moderate schizotypy. Mild-to-moderate schizotypal traits may have a linear relationship with HR during close social interaction because of difficulty with acclimatizing to the social interaction.

The path from schizotypy to depression and aggression and the role of family stress

Background.

Schizotypy is a multidimensional construct that is linked to the vulnerability for psychosis. Positive schizotypy includes having paranormal beliefs. Negative schizotypy includes social anhedonia. Disorganized schizotypy includes social anxiety and communication disorder. Schizotypy relates to depression and aggression. Family stress from high expressed emotion (EE; a rating of criticism, hostility, and emotional overinvolvement in a close relative toward a person showing signs of mental disorder) may mediate the link between schizotypy, depression and aggression. This study tested, using path analyses, the hypotheses that schizotypy predicts depression and aggression through high perceived EE as criticism and irritability (hypothesis 1) and praise and intrusiveness in a close relative (hypothesis 2).

Methods.

One hundred and four healthy participants listened to and rated the self-relevance of standard criticism and standard praise that denote EE. Participants rated their level of schizotypy, depression, aggression, and perceived EE in self-report questionnaires. Two path models tested the hypotheses.

Results.

Disorganized schizotypy, more than positive schizotypy, predicted the path to depression and aggression when perceived criticism and perceived EE-irritability were mediators. Disorganised schizotypy, more than negative schizotypy, predicted the path to depression and aggression when perceived praise and perceived EE-intrusiveness were mediators.

Conclusions.

Greater perceived criticism and less perceived praise in family communication explain the path from disorganized schizotypy (more so than positive or negative schizotypy) to depression and aggression. These findings indicate a need to consider the thought disorder-EE link as a potential contributor to depression and aggression in people with schizophrenia.

Validation of the Chinese version of the Multidimensional Schizotypy Scale (MSS): Convergent evidence from exploratory and confirmatory factor analyses

BACKGROUND

Schizotypy has been shown to be a time-stable construct that exists across the schizophrenia spectrum. The Multidimensional Schizotypy Scale (MSS) was developed to capture the three factors underlying schizotypy: positive, disorganized and negative schizotypy. However, a recent validation study reported a four-factor construct with an additional negative social anhedonia factor. The factor structure of the Chinese version of the MSS remains unknown. This study aimed to identify and validate the factor structure of the Chinese version of the MSS.

METHODS

We recruited 641 Chinese speakers via on-line advertisement. We administered the Chinese version of the MSS, which was a self-report instrument. The scale consists of 77 items with true or false response options. We identified and removed 43 outliers. Finally, a total of 294 participants were randomly selected as the derivative sample for exploratory factor analysis (EFA). The remaining 304 participants were retained as the validation sample for confirmatory factor analysis (CFA).

RESULTS

EFA identified four factors: the positive factor, the disorganization factor, the negative affective and motivational anhedonia factor, and the negative social anhedonia factor. The EFA-identified four-factor model was compared with the unidimensional, three-factor bifactorial and theoretical three-factor models using CFAs. The three-factor bifactorial model fitted the data better than the EFA-identified four-factor model.

CONCLUSION

Our finding suggests that the Chinese version of the MSS is a valid tool for assessing schizotypy in the Chinese setting.

"Formal Thought Disorder" in a General-Community Sample With Elevated Schizotypal Traits

Different dimensions of formal thought disorder (FTD) are distinguished by different patterns of cognitive dysfunction and cortical variability in patients with schizophrenia; however, inconsistent findings may relate to patient-related confounds. Investigating FTD in nonpatient samples with elevated levels of schizotypal traits avoids these confounds, but its utility to FTD research is unknown. Thus, we performed principal components analysis (PCA) of FTD ratings using the Scale for the Assessment of Thought, Language, and Communication (TLC) and the Thought and Language Index (TLI) in a general-community sample with elevated schizotypal traits. Both scales showed "clinically elevated" FTD, particularly, the TLC. PCA described a three-component TLC solution ("disorganization," "verbosity," "emptiness") and a two-component TLI solution ("negative," "idiosyncratic"), generally consistent with schizophrenia research. TLC "disorganization" and "emptiness" were correlated with psychosis-like experiences. TLI "negative" was associated with lower general cognitive function, consistent with schizophrenia research. FTD may have shared etiology along the schizophrenia spectrum.

Sensitivity to criticism and praise predicts schizotypy in the non-clinical population: The role of affect and perceived expressed emotion

BACKGROUND

Schizotypy represents a cluster of personality traits consisting of magical beliefs, perceptual aberrations, disorganisation, and anhedonia. Schizotypy denotes a vulnerability for psychosis, one reason being psychosocial stress. High expressed emotion (EE), a rating of high criticism, hostility, and emotional over-involvement from a close relative, denotes psychosocial stress and vulnerability to psychosis, and is associated with schizotypy. This study aimed to decipher the relationship of schizotypy to perceived criticism and perceived praise in terms of affect and perceived EE.

METHODS

Ninety-eight healthy participants listened to short audio-clips containing criticism, praise, and neutral comments from a stranger, and evaluated them in terms of the comments' arousal and personal relevance. Participants also answered self-report questionnaires of schizotypy, depression, mood, and perceived EE. Correlational analyses tested the relationship between schizotypy and the evaluations of criticism and praise. Mediation analyses then tested whether depression, positive mood, and perceived EE explained these relationships.

RESULTS

Greater relevance of standard criticism correlated with higher positive schizotypy. This association was fully mediated by high depression and perceived irritability from a close relative. Lower relevance of standard praise correlated with higher cognitive disorganisation (another schizotypal trait). This relationship was partially mediated by low positive mood and high perceived intrusiveness from a close relative.

CONCLUSION

Greater perceived criticism and lower perceived praise predict schizotypy in the healthy population. Affect and interpersonal sensitivity towards a close relative explain these relationships, such that depression increases perceived criticism, and positive mood increases perceived praise. Perceived EE defines the interpersonal nature of schizotypy.

Neuropsychological correlates of schizotypy: a systematic review and meta-analysis of cross-sectional studies

INTRODUCTION

Cognitive deficits can precede the onset of psychotic episodes and predict the onset of the illness in individuals with schizotypy traits. In some studies, high levels of schizotypy were associated with impairments in memory, attention, executive functions, and verbal fluency. This review provides a more comprehensive understanding of cognitive impairments related to schizoytpy.

METHODS

 A systematic review of "schizotypy and neuropsychological measures" was conducted, and it retrieved 67 studies. All papers with case-control design showing means and standard deviations from neuropsychological measures were included in a meta-analysis (n = 40). A comparison between our finding and another metaanalysis with patients with schizophrenia-spectrum disorders [Fatouros-Bergman, H., Cervenka, S., Flyckt, L., Edman, G., & Farde, L. (2014). Meta-analysis of cognitive performance in drugnaive patients with schizophrenia. Schizophrenia Research. doi: 10.1016/j.schres.2014.06.034 ] was performed to study the similarities on the MATRICS domains between the two disorders.

RESULTS

We found evidence of worse functioning of verbal and visual-spatial working memory, and of language in people with schizotypy or with schizotypal traits. Working memory deficit is present in both schizotypy and schizophrenia with larger effect sizes compared to other domains.

CONCLUSIONS

 Working memory deficit might be a cognitive marker of the risk of psychosis. Interventions targeting cognitive deficits early may be crucial to the prevention of psychosis.

Body-Size Perception, Body-Esteem, and Parenting History in College Women Reporting a History of Child Abuse

This study investigated the relations among physical, emotional, and sexual abuse up to adolescence and subsequent perception of body size, detection of changes in body size, and body-esteem. The role of parenting history in abused participants was also examined. 38 college undergraduate women, half of whom had been abused, reported instances of abuse, childhood parenting history, and current body-esteem. A recently developed software program of Gardner and Boice was used to present a series of distorted frontal profiles of each participant's own body for the women to rate as being too wide or too thin. A psychophysical procedure called adaptive probit estimation was used to measure the amount of over- and underestimation of these ratings and whether these changes were statistically significant. Analysis showed abused participants had distorted perceptions of body size, although the direction of the distortion was not consistent. There was no difference in detection of changes in body size. Abused and nonabused participants differed on measures of body-esteem and on ratings of most parenting experiences, including experiences with both mothers and fathers.

Individual differences in the executive control of attention, memory, and thought, and their associations with schizotypy

A large correlational study took a latent-variable approach to the generality of executive control by testing the individual-differences structure of executive-attention capabilities and assessing their prediction of schizotypy, a multidimensional construct (with negative, positive, disorganized, and paranoid factors) conveying risk for schizophrenia. Although schizophrenia is convincingly linked to executive deficits, the schizotypy literature is equivocal. Subjects completed tasks of working memory capacity (WMC), attention restraint (inhibiting prepotent responses), and attention constraint (focusing visual attention amid distractors), the latter 2 in an effort to fractionate the "inhibition" construct. We also assessed mind-wandering propensity (via in-task thought probes) and coefficient of variation in response times (RT CoV) from several tasks as more novel indices of executive attention. WMC, attention restraint, attention constraint, mind wandering, and RT CoV were correlated but separable constructs, indicating some distinctions among "attention control" abilities; WMC correlated more strongly with attentional restraint than constraint, and mind wandering correlated more strongly with attentional restraint, attentional constraint, and RT CoV than with WMC. Across structural models, no executive construct predicted negative schizotypy and only mind wandering and RT CoV consistently (but modestly) predicted positive, disorganized, and paranoid schizotypy; stalwart executive constructs in the schizophrenia literature-WMC and attention restraint-showed little to no predictive power, beyond restraint's prediction of paranoia. Either executive deficits are consequences rather than risk factors for schizophrenia, or executive failures barely precede or precipitate diagnosable schizophrenia symptoms. (PsycINFO Database Record

Schizotypy: looking back and moving forward

This article introduces and reviews the history of the construct of schizotypy for the special section appearing in the journal. Schizotypy offers a useful construct for understanding the etiology, development, and expression of schizophrenia-spectrum psychopathology and a unifying construct for linking a broad continuum of clinical and subclinical manifestations. The article reviews the descriptive psychopathology roots of schizotypy, Meehl and Claridge's classical formulations of the construct (including the debate about dimensional vs taxonic structure), and the need for a comprehensive, multidimensional model of schizotypy. The article briefly reviews the wide empirical literature supporting schizotypy and also examines several criticisms and misconceptions about the construct and research methods used to assess it. Finally, the article offers several suggested goals for future schizotypy research.

Cognition and brain function in schizotypy: a selective review

Schizotypy refers to a set of personality traits thought to reflect the subclinical expression of the signs and symptoms of schizophrenia. Here, we review the cognitive and brain functional profile associated with high questionnaire scores in schizotypy. We discuss empirical evidence from the domains of perception, attention, memory, imagery and representation, language, and motor control. Perceptual deficits occur early and across various modalities. While the neural mechanisms underlying visual impairments may be linked to magnocellular dysfunction, further effects may be seen downstream in higher cognitive functions. Cognitive deficits are observed in inhibitory control, selective and sustained attention, incidental learning, and memory. In concordance with the cognitive nature of many of the aberrations of schizotypy, higher levels of schizotypy are associated with enhanced vividness and better performance on tasks of mental rotation. Language deficits seem most pronounced in higher-level processes. Finally, higher levels of schizotypy are associated with reduced performance on oculomotor tasks, resembling the impairments seen in schizophrenia. Some of these deficits are accompanied by reduced brain activation, akin to the pattern of hypoactivations in schizophrenia spectrum individuals. We conclude that schizotypy is a construct with apparent phenomenological overlap with schizophrenia and stable interindividual differences that covary with performance on a wide range of perceptual, cognitive, and motor tasks known to be impaired in schizophrenia. The importance of these findings lies not only in providing a fine-grained neurocognitive characterization of a personality constellation known to be associated with real-life impairments, but also in generating hypotheses concerning the aetiology of schizophrenia.

Validation of the French sensory gating inventory: a confirmatory factor analysis

The Sensory Gating Inventory (SGI) is an instrument investigating daily experiences of sensory gating deficit developed for English speaking schizophrenia patients. The purpose of this study is to design and validate a French version of the SGI. A forward-backward translation of the SGI was performed. The psychometric properties of the French SGI version were analyzed. A confirmatory factor analysis (CFA) was carried out to determine whether factor structure of the French version is similar to the original English version. In a sample of 363 healthy subjects (mean age=31.8 years, S.D.=12.2 years) the validation process revealed satisfactory psychometric properties: the internal consistency reliability was confirmed for each dimension; each item achieved the 0.40 standard threshold for item-internal consistency; each item was more highly correlated with its contributive dimension than with the other dimensions; and based on a CFA, we found a 4-factor structure for the French version of the SGI similar to the original instrument. Test-retest reliability was not determined. The French version of the SGI is a psychometrically sound self-report for measuring phenomenological sensory gating experiences.

A hierarchical finite mixture model that accommodates zero-inflated counts, non-independence, and heterogeneity

A number of mixture modeling approaches assume both normality and independent observations. However, these two assumptions are at odds with the reality of many data sets, which are often characterized by an abundance of zero-valued or highly skewed observations as well as observations from biologically related (i.e., non-independent) subjects. We present here a finite mixture model with a zero-inflated Poisson regression component that may be applied to both types of data. This flexible approach allows the use of covariates to model both the Poisson mean and rate of zero inflation and can incorporate random effects to accommodate non-independent observations. We demonstrate the utility of this approach by applying these models to a candidate endophenotype for schizophrenia, but the same methods are applicable to other types of data characterized by zero inflation and non-independence.

Thought disorder in offspring of schizophrenic parents: findings from the New York High-Risk Project

The goal of the present analyses was to examine the hypothesis that mild forms of thought disorder (TD) may serve as an indicator of genetic liability for schizophrenia. A subset of 232 subjects drawn from the New York High-Risk Project was used to compare individuals at high risk for schizophrenia (ie, offspring of parents with schizophrenia; n = 63) with 2 groups of individuals at low risk for schizophrenia (ie, offspring of parents with affective disorder [n = 52] and offspring of psychiatrically normal parents [n = 117]). Subjects were administered the Rorschach Inkblot Test, and their responses were assessed according to the Thought Disorder Index (TDI). The high-risk offspring displayed significantly more TD than the other 2 groups, as shown by significantly higher TDI scores. Moreover, they had more deviant verbalizations, according to their significantly higher scores on a composite Idiosyncratic Verbalizations score. As expected, the offspring who developed psychosis produced more TD in adolescence than those who did not develop psychosis. In the sample as a whole, TD scores during late adolescence/early adulthood were positively associated with schizotypal features during mid-adulthood. These findings support the assertion that the presence of TD serves as an endophenotypic marker of a schizophrenia diathesis.

Deficient visual sensitivity in schizotypal personality disorder

Schizotypal personality disorder is a personality disorder in the schizophrenia spectrum, sharing genetic and neurobiologic characteristics with schizophrenia. Visual contrast detection, found to be abnormal in chronic schizophrenia, was investigated in schizotypal personality disorder (SPD). Since dopamine in the retina enhances visual contrast detection and SPD patients have relatively reduced dopaminergic activity in the brain compared to schizophrenia patients, it was hypothesized that SPD patients would have decreased to normal contrast sensitivity. Twenty-one subjects with DSM-IV diagnosed SPD, 18 healthy controls, and 12 subjects with a personality disorder unrelated to schizophrenia (OPD) were evaluated for contrast detection using a sinusoidal grating presented at varying temporal frequencies. Subjects also were evaluated neuropsychologically using several standardized neurocognitive tests. A significant effect of subject group was found on the contrast detection threshold (p<0.01) with a significant difference between the SPD group and the healthy control group but not between the OPD group and the healthy control group. The SPD group had higher contrast detection thresholds at all temporal frequencies tested. Correlations were found between contrast detection and performance on the Trail-Making, N-Back, and CPT tasks in SPD patients. These results, based upon a paradigm reflecting dopamine activity in the early visual system, highlight the differences as well as similarities between SPD and schizophrenia with regard to the dopamine system in schizophrenia spectrum (Siever and Davis, 2004).

Schizotypal traits and N400 in healthy subjects

We examined whether correlations previously found between symptoms of schizophrenia patients and the amplitude of an event-related potential (ERP), the N400, could be also found between schizotypal experiences of healthy subjects and the N400. We chose a semantic categorization task previously used with patients. Schizotypal experiences were measured with the schizotypal personality questionnaire (SPQ). The effects of the other factors were controlled for when assessing the correlations between each SPQ factor and N400s. These correlations were assessed at each electrode site to see whether their distribution on the scalp follows that of the N400 effect. Disorganization and interpersonal scores were found to correlate with ERPs in the N400 time window, as previously reported for the comparable symptoms of patients. However, the scalp distribution of these correlations differed from that of the N400 effect.

The Genetic Basis of Thought Disorder and Language and Communication Disturbances in Schizophrenia

Thought disorder as well as language and communication disturbances are associated with schizophrenia and are over-represented in clinically unaffected relatives of schizophrenics. All three kinds of dysfunction involve some element of deviant verbalizations, most notably, semantic anomalies. Of particular importance, thought disorder characterized primarily by deviant verbalizations has a higher recurrence in relatives of schizophrenic patients than schizophrenia itself. These findings suggest that deviant verbalizations may be more penetrant expressions of schizophrenia susceptibility genes than schizophrenia. This paper reviews the evidence documenting the presence of thought, language and communication disorders in schizophrenic patients and in their first-degree relatives. This familial aggregation potentially implicates genetic factors in the etiology of thought disorder, language anomalies, and communication disturbances in schizophrenia families. We also present two examples of ways in which thought, language and communication disorders can enrich genetic studies, including those involving schizophrenia.

Communication disturbances, working memory, and emotion in people with elevated disorganized schizotypy

This study examined whether people with elevated disorganized schizotypy would differ from control participants on characteristics associated with disorganization symptoms in schizophrenia and also whether disorganized schizotypy was associated with problems processing emotion. People with disorganized schizotypy (n=32) exhibited greater communication disturbances (CD) than control participants (n=34) for emotionally negative topics but not for positive topics. In addition, the disorganized group exhibited poorer performance on a working memory task but not on a psychometrically matched verbal intelligence task. In addition, poor working memory was associated with increased CD for negative topics and, after controlling for group differences in working memory, group differences in CD were not significant. Moreover, the disorganized group exhibited greater emotional ambivalence and ambivalence was associated with increased CD in the disorganized group. These results suggest that people with disorganized schizotypy exhibit some similar characteristics to people with schizophrenia who have disorganization symptoms and that disorganized schizotypy is also associated with poor emotion processing.

Dissociative symptom disorders in advanced nursing practice: background, treatment, and instrumentation to assess symptoms

Less well-known among the psychiatric disorders, dissociation is one of the most common underlying symptoms of individuals seeking mental health care (Maldonado, 2001). Closely associated with post-traumatic stress disorder, dissociation characteristics may include inconsistent consciousness, autobiographical forgetfulness, difficulties in self-regulation, regressions, alternate identities, disorganization in the development of a cohesive sense of self, depersonalization, and derealization (Trickett, Noll, Reiffman & Putnam, 2001). The major constructs and dimensions of the dissociative symptom disorders in adults are introduced. Several of the most prominent psychometric instruments that nurses and other mental health clinicians may use as adjuncts to diagnosis and treatment are described.

Schizotypy and individual differences in the frequency of normal associations in verbal utterances

BACKGROUND

Recent empirical evidence [Maher, B.A., Manschreck, T.C., Linnert, J., Candela, S., 2005. Quantitative assessment of the frequency of normal associations in the utterances of schizophrenia patients and healthy controls. Schizophrenia Research 78, 219-224] shows that schizophrenia patients produce an elevated rate of normative thought associations in verbal utterances as measured by an objective computerized procedure. An important theoretical question concerns whether such an elevated rate of associative activity is due merely to psychosis, or can it be found in schizotypic subjects with no prior history of psychosis.

METHODS

We hypothesized that schizotypic features should be correlated with associative performance, especially the positive symptom-like schizotypic features. The present study examined associative performance in psychometrically-identified schizotypic subjects (n=25) and normal control (n=29) subjects. We studied individual differences in schizotypal personality features in relation to the associative performance index.

RESULTS

Level of normative associations was correlated with total schizotypic features, particularly those involving reality distortion and disorganization. Regression analysis revealed higher levels of disorganization features and lower levels of negative schizotypal features uniquely accounted for variation in the associative performance index. Partial correlation analysis suggested that the negative schizotypic features dimension may function as a suppressor variable moderating the relationship between disorganization and level of normative associations.

CONCLUSIONS

Disorganization-related schizotypal features among individuals with no prior history of psychosis are correlated with elevated levels of normative associations. This relationship is most likely moderated by negative schizotypic features. These data support the presence of hyperassociative processes in those deemed to be at elevated risk for schizophrenia (or, more broadly perhaps, psychosis). Our findings support the utility of measuring associative performance using an objective measure and suggest that associative performance may be an endophenotype [Gottesman, I., Gould, T., 2003. The endophenotype concept in psychiatry: etymology and strategic intentions. American Journal of Psychiatry 160, 636-645] for schizophrenia.

Genetically predisposed offspring with schizotypal features: an ultra high-risk group for schizophrenia?

Biomarkers proposed in the schizophrenia diathesis have included neurocognitive deficits in domains such as working memory that implicate prefrontal systems. However, the relationship between these biomarkers and psychopathological markers such as schizotypy has not been systematically assessed, particularly in adolescent offspring of schizophrenia patients. Convergence between these markers may identify individuals at especially high risk for schizophrenia. In the current study the authors assessed whether functional deficits in working memory assessed using the oculomotor delayed response task (ODR) and executive function assessed using the Wisconsin Card Sort task (WCST), and structural deficits in prefrontal cortex, in the adolescent offspring of patients were predictive of schizotypy. Schizotypal offspring made more perseverative errors on the WCST (p<.002) and showed age-related deficits on the ODR task (p<.02) compared to their non-schizotypal counterparts or healthy controls. Reduced gray matter concentration in prefrontal cortex (p<.001) was also associated with schizotypy. Schizotypy in offspring of schizophrenia patients appears to be highly associated with known biomarkers of the illness such as executive function impairment and reductions in cortical gray matter. Furthermore, schizotypy appears to interact with development leading to greater impairment in working memory in schizotypal offspring closer to the typical age of onset of schizophrenia than non-schizotypal offspring. Thus, clinical and neurocognitive biomarkers of the illness appear to be highly interrelated in this sample of at-risk offspring. We propose that schizotypy may define a hyper vulnerable sub-sample among individuals genetically predisposed to schizophrenia and that future studies that attempt to assess risk may benefit from such a convergent approach.

Improving construct validity: Cronbach, Meehl, and Neurath's ship: Comment

Smith's article "On Construct Validity: Issues of Method and Measurement" is a fine tribute to L. J. Cronbach and P. E. Meehl (1955) that clarifies the current state and future directions in the understanding of construct validity. Construct validity is a dynamic process, and fit indices need to be used at the service of understanding, not in place of it. The failure of a study or set of studies to support a construct, a measure, or the theory underlying it admits of many explanations, and the ways scientists interpret such failures are prone to cognitive biases and motivated reasoning. This suggests why metrics designed to index the extent to which observations match expectations can be useful prostheses to scientific judgments. As P. E. Meehl (1954) showed decades ago, quantitative, statistical formulas and indices tend to outperform informal, qualitative judgments, and this applies as much to the way researchers evaluate constructs and measures as to judgments in the consulting room.

Finding the "genuine" schizotype: a model and method for resolving heterogeneity in performance on laboratory measures in experimental psychopathology research

Heterogeneity in the performance of persons affected with schizophrenia or schizotypic psychopathology on various laboratory tasks has long been recognized, both for its consistency across tasks and studies and for the massive methodological and substantive challenges it poses for experimental psychopathology, genetic, and other investigations. Traditional multivariate techniques, such as factor analysis, discriminant function analysis, and cluster analysis, have all been deemed inadequate for resolving heterogeneity, because of one or another statistical limitation. Here, an objective statistical approach based on a formal statistical model that uses the ubiquitous and well-developed expectation-maximization (EM) algorithm (A. P. Dempster, N. M. Laird, & D. B. Rubin, 1977) is presented, which enables one effectively to partition a group of experimental subjects, in this case identified initially using the well-known Perceptual Aberration Scale (L. J. Chapman, J. P. Chapman, & M. L. Raulin, 1978), in a manner that reduces heterogeneity and allows for the separation of what are termed genuine and false-positive schizotypes. The validity of the parsing strategy was supported by reference to other laboratory indexes of relevance to schizophrenia and schizotypy that were not included in the initial EM-based analyses. The potential utility of this approach is discussed with reference to future schizophrenia and schizotypy research.

Higher scores of self reported schizotypy in healthy young males carrying the COMT high activity allele

The gene for COMT is located on chromosome 22q11, an area that has been implicated in the pathogenesis of schizophrenia through linkage studies and through the detection of deletions in schizophrenics and velocardiofacial syndrome patients that often present psychotic symptomatology. Additionally catechol-O-methyl transferase activity has been found increased in schizophrenia and a functional polymorphism in the COMT gene itself has been associated with the disease, as well as with aggression in patients. We tested the hypothesis that COMT genotype for the functional Val158Met might contribute to the variance of self reported schizotypy and aggression scores in the normal population. We genotyped 379 healthy 18- to 24-year-old male individuals who had completed the PAS, SPQ and AQ questionnaires. Our results showed that self-reported schizotypy scores in both questionnaires were significantly related to COMT genotype (P = 0.028 for the PAS and P = 0.015 for the SPQ) with individuals homozygous for the high activity allele showing the highest scores. No significant differences were detected for AQ scores. We conclude that the COMT genotype for the functional Val158Met polymorphism is correlated to self-reported schizotypy in healthy males. This finding is in the same direction as reported findings on schizophrenia and it adds to the list of evidence that COMT or a nearby gene in linkage disequilibrium is involved in the pathogenesis of the disease.

The use of the Ego Impairment Index across the schizophrenia spectrum

The goal of this study was to assess perceptual and thought disturbance, as indexed by the Ego Impairment Index (EII; Perry & Viglione, 1991), a Rorschach-derived measure, across the schizophrenia spectrum. We hypothesized that there would be an increase in EII scores (indicating increased disturbance) across the spectrum from nonpatients to severely disturbed, hospitalized schizophrenia patients. Normal comparison participants (n = 66), students with elevated scores on either the Perceptual Aberration/Magical Ideation or the Physical Anhedonia Scales (n = 24), first-degree relatives of schizophrenia patients (n = 36), participants diagnosed with Diagnostic and Statistical Manual of Mental Disorders (4th ed. [DSM-IV]; American Psychiatric Association, 1994) schizotypal personality disorder (n = 36), outpatient schizophrenia participants (n = 33), and hospitalized schizophrenia patients (n = 56) were studied. As hypothesized, we found increased EII scores in all of the schizophrenia spectrum groups when compared against normal comparison participants. Furthermore, the EII was significantly different between the schizophrenia patients and the other schizophrenia spectrum groups. These findings support the use of the EII as a sensitive measure of perceptual and thought disturbance across the schizophrenia spectrum that yields specific information regarding the type of thinking problems that occur within schizophrenia spectrum subgroups.

Body image, symptoms and insight in chronic schizophrenia

Historically, schizophrenics' body image problems were regarded as related particularly to delusions and hallucinations. However, during the 1980s, the predominant view of the phenomenology of the disorder broadened to include negative symptoms; deviations in schizophrenics' body image underlie various behaviors or allegations concerning the body and should be refocused. The present study attempted to detect body image deviations in chronic schizophrenia using the Body Image Questionnaire (BIQ), which comprises three hypothetical components (anatomical, functional and other psychological components), and to clarify their related clinical characteristics in symptoms and insight. The BIQ was administered to 93 chronic schizophrenics (diagnosed according to DSM IV; 44 men and 49 women) and 177 normals (78 men and 99 women) adults. The combined data of the three BIQ components in schizophrenic and normal subjects were factor-analyzed separately, and factor scores obtained were compared between schizophrenic and normal groups. The factor scores that differentiated groups were further compared between schizophrenic subgroups, determined by high or low scores for positive symptoms assessed by Scale for the Assessment of Positive Symptoms, negative symptoms by Scale for the Assessment of Negative Symptoms and insight by the Schedule for Assessing Insight. Significant differences between diagnostic groups were found in five of nine factor scores. Dullness in movement, powerlessness, unusually strong gastrointestinal function, lifelessness and fragility proved to be the deviated body images in chronic schizophrenic patients. Powerlessness and lifelessness proved to be related to positive and negative symptoms, and unusually strong gastrointestinal function and fragility to insight.

Cognitive slippage in schizotypic individuals

The Miers and Raulin Cognitive Slippage Scale was used to assess subtle thought disorder, and the Wisconsin Card Sorting Test (WCST) was used to assess cognitive performance in deviantly high scorers on the Perceptual Aberration and Magical Ideation Scales (N = 63), high scorers on the revised Social Anhedonia Scale (N = 62), and in control subjects (N = 83). Results indicate that schizotypic individuals are more likely to report greater cognitive slippage and less likely to achieve as many WCST categories as controls. Individuals with both positive and negative symptoms of schizotypy reported higher levels of cognitive slippage than those individuals reporting only negative schizotypy. Additionally, the results confirm the presence of an especially high-risk group of psychosis-prone individuals, namely, those individuals with deviant scores on the revised Social Anhedonia Scale who possess additional indicators of schizotypy.

Brain electric correlates of strong belief in paranormal phenomena: intracerebral EEG source and regional Omega complexity analyses

The neurocognitive processes underlying the formation and maintenance of paranormal beliefs are important for understanding schizotypal ideation. Behavioral studies indicated that both schizotypal and paranormal ideation are based on an overreliance on the right hemisphere, whose coarse rather than focussed semantic processing may favor the emergence of 'loose' and 'uncommon' associations. To elucidate the electrophysiological basis of these behavioral observations, 35-channel resting EEG was recorded in pre-screened female strong believers and disbelievers during resting baseline. EEG data were subjected to FFT-Dipole-Approximation analysis, a reference-free frequency-domain dipole source modeling, and Regional (hemispheric) Omega Complexity analysis, a linear approach estimating the complexity of the trajectories of momentary EEG map series in state space. Compared to disbelievers, believers showed: more right-located sources of the beta2 band (18.5-21 Hz, excitatory activity); reduced interhemispheric differences in Omega complexity values; higher scores on the Magical Ideation scale; more general negative affect; and more hypnagogic-like reveries after a 4-min eyes-closed resting period. Thus, subjects differing in their declared paranormal belief displayed different active, cerebral neural populations during resting, task-free conditions. As hypothesized, believers showed relatively higher right hemispheric activation and reduced hemispheric asymmetry of functional complexity. These markers may constitute the neurophysiological basis for paranormal and schizotypal ideation.

Strauss (1969) revisited: a psychosis continuum in the general population?

Although dichotomously defined for clinical purposes, psychosis may exist as a continuous phenotype in nature. A random sample of 7076 men and women aged 18-64years were interviewed by trained lay interviewers with the Composite International Diagnostic Interview (CIDI). Those with evidence of psychosis according to the CIDI were additionally interviewed by psychiatrists. For the 17 CIDI core psychosis items, we compared a psychiatrist's rating of hallucinations and/or delusions (Clinical Psychosis; sample prevalence 4.2%) with three other possible positive CIDI ratings of the same items: (i) symptom present, but not clinically relevant (NCR Symptom; sample prevalence 12.9%); (ii) symptom present, but the result of drugs or somatic disorder (Secondary Symptom; sample prevalence 0.6%); (iii) symptom appears present, but there is a plausible explanation (Plausible Symptom; sample prevalence 4.0%). Of the 1237 individuals with any type of positive psychosis rating (sample prevalence 17.5%), only 26 (2.1%) had a DSM-III-R diagnosis of non-affective psychosis. All the different types of psychosis ratings were strongly associated with the presence of psychiatrist-rated Clinical Psychosis (NCR Symptom: OR=3.4; 95% CI: 2.9-3.9; Secondary Symptom: OR=4.5; 95% CI: 2.7-7.7; Plausible Symptom: OR=5.8; 95% CI: 4.7-7.1). Associations with lower age, single marital status, urban dwelling, lower level of education, lower quality of life, depressive symptoms and blunting of affect did not differ qualitatively as a function of type of rating of the psychotic symptom, were similar in individuals with and without any CIDI lifetime diagnosis, and closely resembled those previously reported for schizophrenia. Presence of any rating of hallucinations was strongly associated with any rating of delusions (OR=6.7; 95% CI: 5.6-8.1), regardless of presence of any CIDI lifetime diagnosis. The observation by Strauss (1969. Hallucinations and delusions as points on continua function. Arch. Gen. Psychiatry 21, 581-586) that dichotomously diagnosed psychotic symptoms in clinical samples are, in fact, part of a continuum of experiences, may also apply to the general population. The boundaries of the psychosis phenotype may extend beyond the clinical concept of schizophrenia.

Auditory working memory and verbal recall memory in schizotypy

Deficits on verbal memory tasks, as well as on spatial and auditory working memory tasks, have been observed in schizophrenia patients. A useful strategy in the determination of the premorbid indicator status of specific cognitive and memory deficits observed in patients is to examine those persons at increased biological risk for schizophrenia (e.g. first-degree relatives), schizotypal personality disorder patients, and/or psychometrically identified schizotypes for comparable deficits, though perhaps less profound than those seen in actual patients. We examined verbal memory and auditory working memory functioning in 31 schizotypic and 26 normal control subjects from a large randomly ascertained non-clinical university population. Schizotypy status was determined psychometrically using the well-known Perceptual Aberration Scale. Contrary to our theory-guided expectations, noteworthy deficits in verbal memory and auditory working memory were not observed in the schizotypic subjects and the two experimental groups did not differ significantly on any of the memory measures. These results were discussed in light of prior results obtained using the spatial delayed response task (i.e. spatial working memory) and Wisconsin Card Sorting Test performance on these same subjects. The theoretical implications of these findings are discussed in relation to the putative processes involved in the working memory system, as well as in relation to the schizotypy construct.

Two-year stability of Psychosis Proneness Scales and their relations to personality disorder traits

Two-year stability of Physical Anhedonia (PhA), Perceptual Aberration (PER), and Magical Ideation (MI) scale scores and their relation to personality disorder traits were examined. Additionally, the effects of a time-lagged (prospective) versus concurrent measurement of psychosis proneness and personality disorder traits were studied to examine the specificity of MI, PER, and PhA. With a non-college-student sample (n = 404), stability for PhA was sufficiently high, but for PER and MI, stability was moderate to low. The correlations between personality disorder traits and psychosis proneness scales demonstrate that simultaneous assessment leads to a more nonspecific pattern of associations for MI and PER, although the correlation to schizotypal personality disorder traits were the highest. However, prospectively only MI, but neither PER nor PhA, emerged as a significant predictor for schizotypal and paranoid personality disorder traits in multiple-regression analysis. This suggests that MI may allow for a more specific assessment of psychosis proneness than PER.

Behavioral science foundations of the Rorschach test: research and clinical applications

Never without its critics, the Rorschach Test continues to be widely used in clinical settings. The test continues to be criticized vigorously. Rorschach critics appear to fall into two broad groups: those leveling valid methodological concerns about the test s behavioral science foundations and method critics who appear to deny the validity of the test on strictly a priori or theoretical considerations. Many critics do not appear to be acquainted with the extensive Rorschach research literature. The current paper provides an overview of several domains of applied and laboratory Rorschach behavioral science, including statistical power analysis, interobserver agreement and interrater reliability, Rorschach assessment of thought disorder, and emerging research linking Rorschach variables with diagnostic criteria from the DSM-IV, as a means of educating both adherents and detractors alike concerning the test s scientific track record and applicability to clinical assessment.

Hemispheric specialization in schizophrenics with perceptual aberration

Higher rates of left-handedness and atypical lateralization in schizophrenics paired with findings of morphological abnormalities in cerebral asymmetry suggest that the normal patterns of hemisphere specialization for processing verbal and spatial information may be anomalous in schizophrenics. The small number of studies that have addressed this question have produced inconsistent findings and varied with subtype diagnosis, gender, type of task employed, task difficulty, and control of handedness. Conflicting research findings also may be due to confounding from the heterogeneity of the schizophrenic construct and variability in clinical symptoms across patients. The present study was designed to control for factors that may have confounded earlier studies. Because the study used perceptual measures, the relationship between symptoms of perceptual aberration and hemisphere advantages was examined using Chapman et al.'s (1978) Perceptual Aberration Scale (PAS). Fifteen male schizophrenic patients and 14 male controls were administered tachistoscopic letter and facial recognition go/no-go reaction time tasks. Left hemisphere advantages were found for both controls and schizophrenics on the letter task. Right hemisphere advantages were found for controls on the facial task but not schizophrenics. Instead, a strong negative correlation was found between schizophrenics' PAS scores and hemisphere advantages (r = -0.685, p < 0.007). Further analysis identified a subgroup of schizophrenics with perceptual aberration who exhibited reversed left hemisphere advantages that increased as the PAS scores increased. Additional research is needed to determine whether this subgroup of schizophrenics constitutes a meaningful subtype with a distinct disease process that disrupts the development of normal cerebral lateralization. The findings provide further evidence for the importance of examining relationships between schizophrenics' performance on cognitive measures and their symptom patterns.