Visual event-related potentials in schizotypal personality disorder and schizophrenia

Schizophrenia (SZ) occurs among a spectrum of disorders with similar characteristics, including schizotypal personality disorder (SPD). Visual processing disturbances have been reported in both disorders, but it is not yet clear which processes are disturbed in both SZ and SPD, suggestive of a common endophenotype, and which appear only in SZ. In order to address this question, the authors evaluated visual event-related potentials (ERPs) elicited during a line-orientation discrimination task in control, SPD, and SZ participants. Visual ERPs allow specification of both the time course and physiological correlates of visual perception and cognition. SZ patients had smaller P100 and P300a amplitudes and prolonged P300b latency compared to the control group. SZ patients also had smaller N160, N200, P300a, and P300b amplitudes compared to the SPD group. SPD participants did not differ from control participants on any ERP measure. These data documented pervasive abnormalities in visual perception and attention in SZ but not in SPD, suggesting that these visual ERP disturbances may not represent a common endophenotype.     

Context-processing deficits in schizotypal personality disorder

Research suggests that schizotypal personality disorder (SPD) is a part of the spectrum of schizophrenia-related illnesses. This article hypothesizes that a deficit in the representation and maintenance of context is a core cognitive disturbance in schizophrenia and that SPD individuals should demonstrate context-processing deficits. To test this hypothesis, the authors administered 3 versions of their AX-CPT task, designed to assess context processing, to 35 healthy controls and 26 individuals with DSM-IV SPD. They also administered working memory and selective attention tasks. SPD individuals displayed context representation deficits similar to those found in schizophrenia but did not show the same additional deficits in context maintenance. Context processing was strongly associated with working memory and selective attention performance in the SPD individuals.     

Psychological trauma and schizotypal personality disorder

Two studies examined the relation between psychological trauma and schizotypal symptoms. In Study 1, in which 1,510 adults completed telephone interviews, both childhood maltreatment and the experience of an injury or life-threatening event were significantly associated with schizotypal symptoms. In Study 2, in which 303 adults (oversampled for having elevated levels of schizotypal symptoms) completed extensive in-person assessments, both childhood maltreatment and meeting posttraumatic stress disorder (PTSD) Criterion A were significantly associated with schizotypal symptoms. The links between schizotypal symptoms and at least some forms of psychological trauma could not be fully accounted for by shared variance with antisocial and borderline personality disorders, absorption/dissociation, PTSD symptom severity, family history of psychotic disorder, or signs of neurodevelopmental disturbance (as indexed by minor physical anomalies and inconsistent hand use). Schizotypal symptoms were more strongly associated with childhood maltreatment among men than among women, whereas schizotypal symptoms were more strongly associated with PTSD Criterion A among women than among men. Finally, among men, the association between childhood maltreatment and schizotypal symptoms was moderated by signs of neurodevelopmental disturbance.     

Context processing in schizotypal personality disorder: evidence of specificity of impairment to the schizophrenia spectrum

Working memory abnormalities, which are particularly pronounced on context processing tasks, appear relatively specific to schizophrenia spectrum illnesses compared with other psychotic disorders. However, the specificity of context processing deficits to schizotypal personality disorder (SPD), a prototype of schizophrenia, has not been studied. The authors administered 3 versions of the modified AX Continuous Performance Test and an N-back working memory test to 63 individuals with SPD and 25 with other personality disorders, as well as 42 healthy controls. For the AX Continuous Performance Test standard and degraded versions, there was a significant Trial Type x Delay x Group interaction, as SPDs made significantly more errors reflecting poor maintenance of context and fewer errors reflecting good maintenance of context. SPDs also demonstrated poor performance on the N-back, especially at the 2-back condition. Context processing errors and N-back accuracy scores were related to disorganization symptoms. These findings, which are quite similar to those previously reported in patients with schizophrenia, suggest that context processing deficits are specific to the schizophrenia spectrum and are not a reflection of overall psychopathology.     

Emotional correlates of the different dimensions of schizotypal personality disorder

Two studies explored which different dimensions of schizotypal personality disorder (SPD) were associated with negative affect, attention to emotions, clarity of emotions, and emotional intensity/instability. Study 1 included 247 college students, and questionnaires were used to measure SPD. Study 2 included 225 community residents, oversampling for individuals with elevated levels of SPD, and semistructured diagnostic interviews were used to measure SPD. In both studies (a) higher levels of negative affect were associated with higher levels of both cognitive-perceptual and interpersonal symptoms, (b) cognitive-perceptual disturbances were associated with greater attention to emotion, whereas interpersonal disturbances were associated with less attention to emotion, and (c) lower levels of emotional clarity were associated with higher levels of suspiciousness.     

The criminal and personality profile of patients with schizophrenia and comorbid psychopathic traits

Sixty-one male forensic patients who met the DSM-IV criteria for schizophrenia were categorised into high and low psychopathic trait groups using the Psychopathy Checklist: Screening Version. The groups were compared on their criminal history, symptom profile, personality style, risk scores and subsequent institutional violence. Patients with high scores on the PCL:SV had a greater number of previous convictions and were more likely to have a family history of criminality. The high psychopathy-scoring group had higher levels of Positive and Negative Syndrome Scale grandiose and hostile symptomatology, and higher scores on trait impulsivity and aggression. They also had a more coercive, less compliant interpersonal style than the low-psychopathy scoring group. The high-psychopathy scoring group were more likely to be involved in institutional aggression and had higher levels of risk for violence. Patients with schizophrenia and high levels of comorbid psychopathy have a distinctive interpersonal style that may contribute to their greater risk of disruptive institutional behaviour.     

Lateralized perceptual organization deficits on the global-local task in schizotypal personality disorder

Right and left hemisphere contributions to perceptual organization functions were examined using a divided-attention version of the global-local task in a sample of 21 unmedicated participants diagnosed with schizotypal personality disorder (SPD) and 20 controls. The SPD participants showed an abnormal global processing advantage. When the visual angle of the hierarchical stimuli was increased from 3 degrees to 9 degrees, the controls showed an increasing local processing advantage, but the SPD participants continued to show an abnormal global processing advantage. These findings suggest a local processing deficit on divided-attention versions of the global-local task in schizophrenia spectrum disorders. Female SPD participants, who had less severe interpersonal deficit symptoms, showed a more abnormal global processing advantage. Hemispheric and processing resource mechanisms that might explain these findings are discussed.     

Logical reasoning in schizotypal personality

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

Attentional window in schizophrenia and schizotypal personality: Insight from negative priming studies

One of the core deficits that characterizes schizophrenia is an increase in distractibility and disinhibition at all levels of information processing. Patients with schizophrenia seem unable to focus attention on the relevant events while ignoring the irrelevant stimuli. This pattern of behavior is also observed in unmedicated schizotypal individuals who may carry liability for schizophrenia. In this review, we focus on studies of attentional inhibition, as assessed by the negative priming paradigm, to elucidate the relationships among deficits in inhibition, clinical symptoms and medication effects. We then consider models of the etiology of deficits in negative priming in schizophrenia and schizotypal personality. Finally, we discuss the potential power of utilizing hypothesis-driven cognitive paradigms in psychiatric research.     

High-lethality status in patients with borderline personality disorder

Recurrent suicidal behaviors in patients with Borderline Personality Disorder (BPD) are often considered communicative gestures; however, 10% complete suicide. This study seeks to identify risk factors for suicide within a BPD sample by comparing patients with High- and Low-Lethality attempts. BPD attempters (n = 113) were assessed on demographic, diagnostic, and personality variables: clinical symptoms, suicidal behaviors; childhood, family, and treatment histories; social adjustment; and recent life events. Forty-four High-Lethality attempters, defined by a score of 4 or more on Beck's Medical Lethality Scale, were compared to 69 Low-Lethality attempters. Discriminating variables were entered in a multivariate logistic regression model to define predictors of High-Lethality status. High-Lethality attempters were older, with children, less education, and lower socioeconomic class (SES) than Low-Lethality attempters. They were more likely to have Major Depressive Disorder (MDD), co-morbid Antisocial Personality Disorder (ASPD), and family histories of substance abuse. They reported greater intent to die, more lifetime attempts, hospitalizations, and time in the hospital. High-Lethality status was best predicted by low SES, co-morbid ASPD, extensive treatment histories, and greater intent to die. These characteristics resemble profiles of patients who complete suicide, are not specific for BPD, and do not include impulsivity, aggression, or severity of BPD criteria.     

Childhood abuse in Chinese patients with borderline personality disorder

This study examined (1) the relative prevalence of childhood abuse and other pathological childhood experiences in China reported by outpatients with borderline personality disorder (BPD), with other personality disorders, and without personality disorders; and, (2) whether the primary predictors of BPD in North America are associated with the development of BPD in China. The childhood experiences of 203 outpatients with BPD, 109 outpatients with other personality disorders, and 70 outpatients without Axis II diagnoses were assessed with the Chinese version of the Childhood Experience of Care and Abuse Questionnaire (CECA.Q). Patients with BPD reported significantly more physical, emotional, and sexual abuse than either comparison group. Four types of childhood experiences were significant predictors of BPD: maternal neglect, paternal antipathy, sexual abuse, and maternal physical abuse. The findings suggest that maternal physical abuse is as strong a predictor of BPD in China as sexual abuse, a finding not replicated in North America.     

The heterogeneous structure of schizotypal personality disorder: item-level factors of the Schizotypal Personality Questionnaire and their associations with obsessive-compulsive disorder symptoms, dissociative tendencies, and normal personality

A. Raine et al.'s (1994) 3-factor scheme is currently the most widely accepted model of schizotypal personality disorder (SPD). Factor analytic studies of the Schizotypal Personality Questionnaire (SPQ; A. Raine, 1991) subscales, which represent the 9 Diagnostic and Statistical Manual of Mental Disorders (DSM) criteria for SPD, have provided the model's primary support. The use of only 9 modeled variables, however, limits the number of factors that can be extracted. To explicate this structure more fully, the authors conducted item-level factor analyses of the SPQ in a large student sample that completed the instrument twice within a 2-week interval. The authors' analyses failed to support either the 3-factor model of SPD or the 9 existing DSM-based subscales of the SPQ. Instead, 5 replicable dimensions emerged that capture recurrent symptom pairings found in the broader SPD literature: Social Anhedonia, Unusual Beliefs and Experiences, Social Anxiety, Mistrust, and Eccentricity/Oddity. These factors are only weakly correlated with each other and show differential correlational patterns with the Big Five personality traits, dissociative tendencies, and symptoms of obsessive-compulsive disorder. Moreover, they are congruent with dimensional models of personality psychopathology. Implications for SPD in DSM-V are discussed.     

Schizotypy and pathological personality profile in siblings of patients with psychosis

Schizotypy has been proposed to be the expression of the genetic vulnerability to schizophrenia. Schizotypal features have been associated with personality dimensions found in patients with psychosis. In this study, we compared the Dimensional Assessment of Personality Pathology - Basic Questionnaire (DAPP-BQ) scores of patients with psychosis, siblings scoring higher on schizotypy (SSHS), and siblings scoring lower (SSLS). The SSHSs displayed a DAPP-BQ profile characterized by high scores in the dimensions of affective lability, anxiousness, submissiveness, social avoidance, identity problems, oppositionality, narcissism, and restricted expression, distinguishing them from the SSLS. Due to these dimensions, SSHSs are more similar to the patients' DAPP-BQ profile. The results suggest that this pathological personality profile might contribute to increase the risk of developing psychosis in siblings who have more schizotypal features.     

Intra-individual reaction time variability in schizophrenia, depression and borderline personality disorder

Intra-individual reaction time variability (IIV) in neuropsychological task performance reflects short term fluctuations in performance. Increased IIV has been reported in patients with schizophrenia and could be related to a deficient neural timing mechanism, but the role of IIV in adult patients with other psychiatric disorders has not been established. Therefore, we compared IIV measures obtained in a Go/Nogo task from patients with schizophrenia, major depression and borderline personality disorder. IIV was increased for patients with schizophrenia. When correcting for differences in mean reaction time, depressive and borderline patients also showed increased IIV. Importantly, all groups showed a strong association between IIV and accuracy of task performance. This suggests that increased IIV might be a sensitive marker for the efficiency of top-down attentional control in all diagnostic groups. Aside from these similarities, the complete results including measures of IIV, mean reaction time and accuracy show differential patterns for patients with schizophrenia compared to those with borderline personality disorder or depression. These results are discussed with respect to common versus disorder-specific neural mechanisms underlying increased IIV.     

Sex differences in schizotypal personality in a nonclinical population.

This study tests the hypothesis that normal women will score higher on the more "positive" features of schizotypal personality and normal men will score higher on more "negative" schizotypal features. Two samples (n = 393, 394) were administered the Schizotypal Personality Questionnaire, which contains subscales corresponding to the 9 schizotypal personality traits outlined in the Diagnostic and Statistical Manual of Mental Disorders (rev. 3rd ed.; American Psychiatric Association, 1987). Women scored significantly higher on the positive subscales of Ideas of Reference and Odd Beliefs/Magical Thinking, and men scored significantly higher on the negative subscales of No Close Friends and Constricted Affect. These findings replicated from one sample to another. These results are broadly consistent with previous findings on schizotypal personality and schizophrenia. It is hypothesized that sex differences in schizophrenic symptomatology may in part reflect an exaggeration of normal sex differences in the general population.     

Emotional responses in patients with borderline as compared with avoidant personality disorder

The aim of this study was to assess psychophysiological affect correlates, in addition to the usual self-report in borderline personality disorder (BPD) compared with avoidant personality disorder (APD) and normal controls (NCs), when responding to standardized experimental stimuli. In 24 BPD female patients, 23 APD female patients, and 27 female NCs, skin conductance response (SCR), heart rate (HR) change, and startle response were recorded while the subjects viewed slides with emotional content. Neither the self-report nor the psychophysiological data supported the hypothesis that affective responses of BPD individuals are generally stronger than those with APD. BPD patients showed no potentiation of the affective modulation of the startle reflex and their electrodermal reactivity was lower than in either the APD subjects or the NCs. The hypothesis of a general affective hyperresponsivity could not be confirmed. Low somatic arousal in BPD can interfere with the anticipation of signal stimuli and may explain the exaggerated openness borderline personalities show to stimuli, particularly in interpersonal situations.