Impairment of story memory organization in patients with schizophrenia

The aim of the present paper was to examine the organization of story memory in schizophrenia. Participants were 35 patients with schizophrenia and 24 healthy subjects who completed the Wechsler Memory Scale-Revised. The organization of story memory was evaluated with the Logical Memory subtest. Schizophrenia patients scored significantly lower than controls on thematic sequencing, and significant negative correlations were found between positive symptoms and thematic sequencing. These findings suggest that schizophrenia has deficits in organization of story memory, which are related to symptoms such as disorganized thoughts and behavior.     

精神分裂症患者的工作记忆损伤研究

目的 探讨精神分裂症患者和正常人之间空间、语音及面孔工作记忆的差异.方法 分别对44名精神分裂症患者和40名健康成年人进行空间、语音及面孔工作记忆测试,比较两组任务成绩及反应时间的差异.结果 患者在进行空间工作记忆和面孔工作记忆任务时,准确率明显低于对照组,空间工作记忆(患者组:86.12+12.4%,对照组:91.63+6.18%,P1=0.014),面孔工作记忆(患者组:63.01+9.04%,对照组:69.14+9.24%,P2=0.003),而进行语音工作记忆任务时,两组准确率无统计学差异(P=0.42)患者在进行三项工作记忆测试时,耗时均较对照组长(P<0.05).结论 患者工作记忆损伤存在不均衡性,可能与精神分裂症损伤的脑区不同有关.     

Visuospatial working memory in schizotypal personality disorder patients

BACKGROUND: Cognitive processing deficits have been identified as an abnormality that schizotypal personality disorder (SPD) individuals share with schizophrenic patients. It has been hypothesized that impaired working memory may be a critical component of several of the more complex cognitive deficits found in schizophrenia spectrum patients. METHOD: 18 DSM-III-R SPD patients, and 17 normal comparison subjects were compared on a pen and paper visuospatial working memory task. Moreover, we identified a second psychiatric comparison group comprised of nine patients with other, non-odd cluster personality disorder diagnoses who met no more than one of the SPD criteria and were also tested on the same task. Each person was given 14 immediate recall trials and 10 trials using a 10 s delay. RESULTS: SPD patients performed significantly worse than normal control subjects on the working memory task. SPD patients also performed significantly worse compared to the non-schizophrenia-related personality disorder psychiatric comparison group. CONCLUSIONS: Like schizophrenic patients, SPD patients demonstrate working memory impairment compared to normal controls. This impairment may be specific to the schizophrenia-related personality disorders.     

Impairment of incidental memory for frequency in patients with obsessive-compulsive disorder.

The aim of our study was to investigate whether patients with obsessive-compulsive disorder (OCD) have impaired incidental memory for frequency. Fifty-four subjects (27 OCD patients and 27 matched control subjects) performed a task assessing estimation of occurrence of previously heard words. Performance on this task was compared with other intentional verbal memory tasks (recognition, recall and learning of common words). We also correlated memory for frequency with frontal lobe tests (Wisconsin Card Sorting Test, Trail Making Tests A and B, and verbal fluency). Performance on incidental learning of frequency was significantly worse in the OCD group than in control subjects. Other verbal memory measures did not show significant differences. Performance in the frequency task correlated with verbal fluency. Although intentional verbal memories are normal in OCD patients, incidental memory for frequency is impaired, suggesting that prefrontal systems are involved in OCD.     

Visuo-perceptual organization and working memory in patients with schizophrenia

We explore the mechanisms sub-tending the re-organization and memorization of visual information by studying how these mechanisms fail in patients with schizophrenia. Several studies have suggested that patients have difficulties in organizing information in perception and memory. We explore to what extent prompting patients to group items influences memory performance. We distinguish automatic grouping from top-down grouping processes, which are especially involved in re-organizing information. The main task was to memorize pairs of figures. Following manipulation of proximity, pairs of figures were part of the same perceptual group (within-group pair, formed on the basis of automatic grouping) or belonged to different groups (between-group pairs, re-grouped through top-down processes). Prior to the memory task, subjects ran a perception task prompting them to prioritize either within-group or between-group pairs. Unlike patients, controls globally benefited from grouping by proximity in the memory task. In addition, the results showed that prioritizing between-group pairs had a deleterious effect in patients, but with a large decrement in memory performance in the case of within-group rather than between-group figures. This occurred despite preserved focalization on within-group figures, as shown by eye-movement recordings. The suggestion is that when patients are prompted to re-group separate items, they can do so, but the benefit derived from automatic grouping is then not only lost but also reversed. This suggests re-organizing visual information not only involves re-grouping separate items but also integrating these new groups in a unified representation, which is impaired in patients with schizophrenia.     

Longitudinal volume changes of the pituitary gland in patients with schizotypal disorder and first-episode schizophrenia

An enlarged volume of the pituitary gland has been reported in the schizophrenia spectrum, possibly reflecting the hypothalamic-pituitary-adrenal (HPA) hyperactivity. However, it remains largely unknown whether the pituitary size longitudinally changes in the course of the spectrum disorders. In the present study, longitudinal magnetic resonance imaging (MRI) data were obtained from 18 patients with first-episode schizophrenia, 13 patients with schizotypal disorder, and 20 healthy controls. The pituitary volume was measured at baseline and follow-up (mean, 2.7 years) scans and was compared across groups. The pituitary volume was larger in the schizophrenia patients than controls at baseline, and both patient groups had significantly larger pituitary volume than controls at follow-up. In a longitudinal comparison, both schizophrenia (3.6%/year) and schizotypal (2.7%/year) patients showed significant pituitary enlargement compared with controls (− 1.8%/year). In the schizophrenia patients, greater pituitary enlargement over time was associated with less improvement of delusions and higher scores for thought disorders at the follow-up. These findings suggest that the pituitary gland exhibits ongoing volume changes during the early course of the schizophrenia spectrum as a possible marker of state-related impairments.     

Early stage vision in schizophrenia and schizotypal personality disorder

Previous studies of visual perception have reported deficits in contrast sensitivity and dot motion discrimination in schizophrenia. We tested whether these deficits also appear in schizotypal personality disorder (SPD). SPD appears to be genetically and symptomatically related to schizophrenia, but without the marked psychosocial impairment associated with psychotic disorders. The present study investigated contrast sensitivity for moving and static gratings, form discrimination and dot motion discrimination in 24 patients with schizophrenia or schizoaffective disorder (SZ), 16 individuals with SPD, and 40 control subjects. SZ, but not SPD subjects, showed impairments on tests of contrast sensitivity for static and moving gratings, form discrimination in noise, and dot motion discrimination. Visual performance did not differ between medicated SZ patients and patients withdrawn from medication. These results confirm early stage visual deficits in schizophrenia regardless of medication status. SPD subjects, in contrast, show intact early stage visual processing despite the presence of marked schizotypal symptoms.     

Visual perception and working memory in schizotypal personality disorder

OBJECTIVE: Patients affected by schizophrenia show deficits in both visual perception and working memory. The authors tested early-stage vision and working memory in subjects with schizotypal personality disorder, which has been biologically associated with schizophrenia. METHOD: Eleven subjects who met DSM-III-R criteria for schizotypal personality disorder and 12 normal comparison subjects were evaluated. Performance thresholds were obtained for tests of visual discrimination and working memory. Both form and trajectory processing were evaluated for each task. RESULTS: Subjects with schizotypal personality disorder showed intact discrimination of form and trajectory but were impaired on working memory tasks. CONCLUSIONS: These data suggest that subjects with schizotypal personality disorder, unlike patients affected by schizophrenia, have relatively intact visual perception. Subjects with schizotypal personality disorder do show specific deficits on tasks of comparable difficulty when working memory demands are imposed. Schizotypal personality disorder may be associated with a more specific visual processing deficit than schizophrenia, possibly reflecting disruption of frontal lobe systems subserving visual working memory operations.     

Relationship of schizotypal personality disorder to schizophrenia: genetics

The adoptive, family, and twin studies show that schizotypal personality features are found among the relatives of schizophrenics. However, it has not been shown that there is a higher risk of schizophrenia among the relatives of schizotypals. An explanation may be that the current DSM-III criteria of schizotypal personality disorder do not adequately define schizotypals genetically related to schizophrenia. While some of the cases that meet DSM-III criteria are within the schizophrenia spectrum, others are unrelated to schizophrenia. There is reason to believe that schizotypals characterized by distant relationship to others, suspiciousness, eccentricity, peculiar communication, and dysfunctional school and work performance are within the schizophrenic sphere, while individuals with psychotic-like symptoms phenomenologically similar to schizophrenia and diagnosed as schizotypal personality disorders in DSM-III represent decompensation of other personality disorders.     

Childhood-onset schizotypal disorder: a follow-up study and comparison with childhood-onset schizophrenia

OBJECTIVE: This paper presents results from the UCLA Follow-Up Study of Childhood-Onset Schizophrenia (SZ) Spectrum Disorders. METHOD: We assessed 12 children with schizotypal personality disorder (SPD) and 18 children with schizophrenia 1-7 years following initial project intake. RESULTS: There was significant continuity between SZ spectrum disorders in childhood and adolescence. Although not all children who presented initially with SZ spectrum disorders continued to meet criteria for SZ spectrum disorder as they progressed through the follow-up period, rates of SZ spectrum disorders ranged from 75% to 92% across the 3 follow-up years for children initially presenting with SPD, and from 78% to 89% for children initially presenting with SZ. CONCLUSION: The most common clinical outcome for children with SPD was continuing SPD, supporting the hypothesis of continuity between childhood and later SPD. However, 25% of the SPD sample developed more severe SZ spectrum disorders (schizophrenia or schizoaffective disorder), also supporting the hypothesis that SPD represents a risk or precursor state for more severe SZ spectrum disorders.     

Functional impairment in patients with schizotypal, borderline, avoidant, or obsessive-compulsive personality disorder

OBJECTIVE: The purpose of this study was to compare psychosocial functioning in patients with schizotypal, borderline, avoidant, or obsessive-compulsive personality disorder and patients with major depressive disorder and no personality disorder. METHOD: Patients (N=668) were recruited by the four clinical sites of the Collaborative Longitudinal Personality Disorders Study. The carefully diagnosed study groups were compared on an array of domains of psychosocial functioning, as measured by the Longitudinal Interval Follow-Up Evaluation--Baseline Version and the Social Adjustment Scale. RESULTS: Patients with schizotypal personality disorder and borderline personality disorder were found to have significantly more impairment at work, in social relationships, and at leisure than patients with obsessive-compulsive personality disorder or major depressive disorder; patients with avoidant personality disorder were intermediate. These differences were found across assessment modalities and remained significant after covarying for demographic differences and comorbid axis I psychopathology. CONCLUSIONS: Personality disorders are a significant source of psychiatric morbidity, accounting for more impairment in functioning than major depressive disorder alone.     

Psychopathy and violent behavior among patients with schizophrenia or schizoaffective disorder.

OBJECTIVE: Although a strong association between violence and psychopathy has been demonstrated in nonpsychotic forensic populations, the relationship between psychopathy and violence among patients with schizophrenia has not been thoroughly explored. Patients with and without a history of persistent violent behavior were compared for comorbidity of psychopathy and schizophrenia or schizoaffective disorder. METHODS: Violent and nonviolent patients were identified through reviews of hospital charts and records of arrests and convictions. The Psychopathy Checklist: Screening Version was administered to 51 patients, 26 violent patients and 25 matched nonviolent patients. Analysis of variance was used as the principal statistical method for comparing violent and nonviolent groups. RESULTS: Mean psychopathy scores were higher for violent patients than nonviolent patients. Five of the violent patients (19 percent) had scores exceeding the cutoff for psychopathy, and 13 (50 percent) scored in the possible psychopathic range. All of the nonviolent patients scored below the cutoff for possible psychopathy. Higher psychopathy scores were associated with earlier age of onset of illness and more arrests for both violent and nonviolent offenses. CONCLUSIONS: The comorbidity of schizophrenia and psychopathy was found to be higher among violent patients than among nonviolent patients. Violent patients with schizophrenia who score high on measures of psychopathy may have a personality disorder that precedes the emergence of psychotic symptoms, or they may constitute a previously unclassified subtype of schizophrenia, characterized by early symptoms of conduct disorder symptoms and persistent violent behavior.     

WCST performance and schizotypal features in the first-degree relatives of patients with schizophrenia.

Since the findings concerning the Wisconsin Card Sorting Test (WCST) performance of healthy first-degree relatives of patients with schizophrenia are equivocal, it still remains unclear whether the WCST may serve as a neuropsychological indicator of vulnerability to schizophrenia. The aim of this study was to evaluate whether the first-degree relatives' schizotypal features could account for these discrepancies. The subjects were 24 schizophrenic probands, 49 of their first-degree relatives and 41 normal controls. The computerized version of the WCST was used and schizotypy features were assessed using four of Chapman's scales. The patient group performed worse on the WCST and had higher scores of schizotypy than the control group. The relatives group did not significantly differ from the control, neither on the WCST performance nor on the scores of schizotypy. However, the subgroup of relatives and the subgroup of patients with high scores on the negative dimension of schizotypy showed a worse performance on the WCST than the subgroups with low scores. There were no differences on the WCST performance between the subgroups with high vs. low scores on the positive dimension of schizotypy. Thus, discrepancies across studies could be explained by a confounding factor represented by the negative dimension of schizotypy.     

Striatal size and relative glucose metabolic rate in schizotypal personality disorder and schizophrenia.

BACKGROUND: Schizotypal personality disorder (SPD) shares social deficits and cognitive impairment with schizophrenia, but is not typically characterized by frank psychosis. Because striatal size and functional activity have both been shown to be associated with psychotic symptoms, we carried out the first study of SPD to assess the caudate and putamen for comparison with findings in schizophrenia. METHODS: Patients with SPD (n = 16), schizophrenic patients (n = 42), and age- and sex-matched normal control subjects (n = 47) were assessed with magnetic resonance imaging. All of the patients with SPD and subsamples of the schizophrenic patients (n = 27) and control subjects (n = 32) were also assessed with positron emission tomography using fluorodeoxyglucose F-18. RESULTS: The relative size of the putamen in controls was significantly larger than in patients with SPD and significantly smaller than in schizophrenic patients, while the relative size of the caudate was similar in all 3 groups. Compared with control values, relative glucose metabolic rate in the ventral putamen was significantly elevated in patients with SPD and reduced in schizophrenic patients. When subsamples of schizophrenic patients (n = 10) and patients with SPD (n = 10) both of whom never received medication were compared, this pattern was more marked, with the highest value for the putamen being found in patients with SPD for the ventral slice and the lowest value for the right dorsal putamen. CONCLUSIONS: Patients with SPD showed reduced volume and elevated relative glucose metabolic rate of the putamen compared with both schizophrenic patients and controls. These alterations in volume and activity may be related to the sparing of patients with SPD from frank psychosis.     

Neuropsychological performance in schizotypal personality disorder: importance of working memory

BACKGROUND: Cognitive deficits consistently have been reported in schizophrenia patients and in patients with schizotypal personality disorder. For this study, the authors wanted to identify which of the domains of cognitive impairment represent "core" deficits of schizophrenia, comparing subjects with schizotypal personality disorder to two comparison groups: healthy volunteers and patients with personality disorders unrelated to schizophrenia. METHOD: Three groups completed a neuropsychological battery: patients with DSM-III-R schizotypal personality disorder (N=82); patients with DSM-III-R personality disorders unrelated to schizophrenia (i.e., a personality disorder other than schizotypal, schizoid, or paranoid [N=44]); and healthy volunteers (N=63). The battery included the California Verbal Learning Test, Trailmaking Test parts A and B, the Dot test of working memory, the Stroop Color and Word Test, the Paced Auditory Serial Addition Test, the WMS visual reproduction test, and the WAIS-R vocabulary and block design. RESULTS: Normative standards for performance that controlled for age, gender, and education were created from the scores of the healthy volunteers. Overall, schizotypal personality disorder patients performed significantly worse than the healthy volunteers and those with personality disorders unrelated to schizophrenia. Specifically, patients with schizotypal personality disorder demonstrated impaired performance on the Paced Auditory Serial Addition Test, WMS visual reproduction test, Dot test, and California Verbal Learning Test. In addition, in a regression analysis, performance on the Paced Auditory Serial Addition Test demonstrated the largest effect size. Indeed, it accounted for unique variance above and beyond all other cognitive measures, since controlling for Paced Auditory Serial Addition Test performance abolished group differences across all other measures. CONCLUSIONS: Patients with schizotypal personality disorder demonstrated moderate cognitive impairment compared with healthy volunteers (significant for seven out of 11 measures). These differences reached statistical significance for tasks of working memory, episodic memory, and delayed recall. Working memory performance accounted for the group differences. This study supports the view that working memory represents a core deficit of schizophrenia spectrum disorders.     

Impairment of temporal attention in patients with schizophrenia

Evidence is accumulating that attention impairment is a core cognitive deficit in patients with schizophrenia. Here we investigate whether they are impaired in the temporal deployment of attention. Specifically, we explore how allocation of processing resources at one time point might affect the processing of a subsequent event differently in normal and schizophrenia subjects. Thirty patients and 31 age- and education-matched control subjects participated in a rapid serial visual presentation task, in which two targets (T1 and T2) were presented in rapid succession among a number of distractors. Subjects were required to identify T1 and detect T2. The sensitivity of T2 detection was analyzed with signal detection theory. The results showed that the attentional blink (the impairment in T2 detection following the identification of T1) is increased in magnitude and protracted in the patients. This observation suggests a less efficient mechanism in temporal gating of attention and in processing rapidly changing visual stimuli in schizophrenia patients.     

Neuropsychological deficit in newly diagnosed patients with schizophrenia or schizophreniform disorder

Forty-six patients with schizophrenia or schizophreniform disorder admitted to hospital for the first time were compared with 21 healthy volunteers on neuropsychological tests reflecting prefrontal and left respectively right hemisphere function. The patients with schizophrenia or schizophreniform disorder had a poorer performance on neuropsychological tests (such as Wisconsin Card Sorting) compared with healthy volunteers. Both left and right hemisphere seemed to be involved. Especially poor performance was found on somewhat complicated tests requiring ability of analysis, abstraction and memory, thus indicating dysfunction of prefrontal and temporohippocampal regions. Signs of sulcal enlargement and size of lateral ventricles on computed tomographic scan correlated with poor test performance on some tests both in patients and in healthy volunteers. No correlations were found between performance on neuropsychological test and negative symptoms.     

Discourse cohesion in the verbal interactions of individuals diagnosed with autistic disorder or schizotypal personality disorder

Autistic disorder and schizotypal personality disorder have been characterised as social communication spectrum disorders. However, it is not clear whether, or by what parameters, the two disorders differ with regard to social use of language. This study compares highfunctioning adolescents with autism and cognitively similar adolescents with schizotypal personality disorder in one aspect of social language use, namely referencing. Cohesion analysis is used to examine pronominal, demonstrative, and comparative references in dialogue from semi-structured interviews. The study finds that adolescents with schizotypal personality disorder use cohesiveties of reference more often and more correctly than do the adolescents with autism. However, both groups have similar rates, types, and patterns of cohesive reference errors. These results indicate that referencing skills in individuals with autism and schizotypal personality disorder are faulty in similar ways, producing similar disruptive effects on the smooth flow of discourse. The results lend support to the concept of a continuity of deficits in social language use in autism and schizotypal personality disorder.     

Eye tracking impairment in clinically identified patients with schizotypal personality disorder

Eye tracking accuracy, which has been found to be impaired in schizophrenic patients and their relatives, was assessed in 26 patients with schizotypal personality disorder, 17 control subjects with other non-schizophrenia-related personality disorders, 29 normal control subjects, and 44 schizophrenic patients. Both schizotypal and schizophrenic patients, but not control subjects with other personality disorders, demonstrated significantly more impaired tracking than the normal control subjects. These results suggest that patients with clinically defined schizotypal personality disorder may be biologically related to schizophrenic patients as part of a spectrum of schizophrenia-related disorders.