Neuropsychological differences among empirically derived clinical subtypes of schizophrenia.

Neuropsychological profile differences between empirically derived clinical subtypes of schizophrenia were examined. Two hundred five patients and 209 demographically matched controls were administered a neuropsychological battery examining 8 domains. Subtypes included negative, disorganized, paranoid, Schneiderian, and mild. All subtypes displayed a neuropsychological profile of generalized impairment with greater deficits in learning, memory, and attention. Results were suggestive of diffuse cognitive dysfunction in schizophrenia with more severe deficits in learning and memory relative to executive skills. This pattern of greater learning and memory impairment was pronounced for disorganized patients. In contrast, paranoid patients outperformed disorganized and negative patients in several domains. These findings reflect bilateral frontal–temporal dysfunction, particularly in disorganized and negative patients. Subtype differences highlight the importance of conceptualizing schizophrenia as a multifocal disorder. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive processing of multidimensional stimuli in schizophrenia: Formal modeling of judgment speed and content.

This article presents a formal, mathematical account of relations between response times on simple cognitive tasks and content of complex judgments involving multiple stimulus dimensions for people with schizophrenia. Changes in multidimensional judgments were viewed as the result of interference from increased stages of encoding with respect to the individual dimensions. Information on dimensional properties encoded earlier in a judgment trial was considered to be more susceptible to loss over the rest of the trial, because of a larger number of encoding stages applied to the remaining dimensional properties. Model predictions were tested with samples of paranoid and nonparanoid schizophrenic participants and controls. Unidimensional encoding speed was assessed by reaction times in an explicit similarity ratings task, and multidimensional judgment content was assessed by the relative importance of different stimulus dimensions to participants' ratings in an implicit similarity ratings task. Results support validity of the model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recognition of posed and genuine facial expressions of emotion in paranoid and nonparanoid schizophrenia.

Most previous research reporting emotion-recognition deficits in schizophrenia has used posed facial expressions of emotion and chronic-schizophrenia patients. In contrast, the present research examined the ability of patients with acute paranoid and nonparanoid (disorganized) schizophrenia to recognize genuine as well as posed facial expressions of emotion. Evidence of an emotion-recognition deficit in schizophrenia was replicated, but only when posed facial expressions were used. For genuine expressions of emotion, the paranoid-schizophrenia group was more accurate than controls, nonparanoid-schizophrenia patients, and depressed patients. Future research clearly needs to consider the posed versus genuine nature of the emotional stimuli used and the type of schizophrenia patients examined. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Can I trust you? Negative affective priming influences social judgments in schizophrenia.

Successful social interactions rely on the ability to make accurate judgments based on social cues as well as the ability to control the influence of internal or external affective information on those judgments. Prior research suggests that individuals with schizophrenia misinterpret social stimuli and this misinterpretation contributes to impaired social functioning. We tested the hypothesis that for people with schizophrenia, social judgments are abnormally influenced by affective information. Twenty-three patients with schizophrenia and 35 healthy control participants rated the trustworthiness of faces following the presentation of neutral, negative (threat-related), or positive affective primes. Results showed that all participants rated faces following negative affective primes as less trustworthy than faces following neutral or positive primes. Importantly, this effect was significantly more pronounced for participants with schizophrenia, suggesting that schizophrenia may be characterized by an exaggerated influence of negative affective information on social judgment. Furthermore, the extent that the negative affective prime influenced trustworthiness judgments was significantly associated with patients' severity of positive symptoms, particularly feelings of persecution. These findings suggest that for people with schizophrenia, negative affective information contributes to an interpretive bias, consistent with paranoid ideation, when judging the trustworthiness of others. This bias may contribute to social impairments in schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impairment of the semantic network in schizophrenia

It is well established that patients with schizophrenia display a variety of language impairments. Despite considerable research, however, the underlying mechanisms of the language deficits in schizophrenia remain unclear. Representations of semantic networks of 56 patients with schizophrenia and 28 normal comparison (NC) subjects of similar ages and educational levels were generated by multidimensional scaling and Pathfinder analyses of their responses on the Animal Fluency Test. On the basis of traditional scoring techniques (i.e., total number of correct animal names generated in 60 s), all patients performed significantly worse than the NC subjects. More detailed analyses of the underlying semantic networks revealed that performance in the patients varied according to age of onset and subtype of schizophrenia. The semantic network of patients with late-onset schizophrenia (i.e., with onset after age 45) was virtually identical to that of the NC group. In contrast, the semantic network of patients with a younger age of onset was disorganized and differed significantly from that of the NC subjects. Findings demonstrated that patients with nonparanoid subtypes displayed greater disorganization in their semantic networks than patients with a paranoid subtype. Although general fluency impairments (e.g., difficulties in initiation, retrieval, and search mechanisms) may be sensitive to schizophrenia, per se, specific deficits in the structure of semantic knowledge may be associated with certain characteristics of individual patients with schizophrenia, such as an earlier age of onset and nonparanoid subtype.     

Same–different judgments in paranoid and schizophrenic patients: A laterality study.

12 normal, 12 paranoid, and 12 nonparanoid schizophrenic Ss were presented with arrays of stimuli to the left, right, or both hemispheres and told to say whether all the stimuli in the array were the same or different. Results fail to confirm the hypothesis that there is a dysfunction of hemispheric operation in paranoid or nonparanoid schizophrenia. There was, however, some evidence that paranoid patients scanned more than did nonparanoid or control Ss. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parietal lobe syndrome and schizophrenia: Comparison of neuropsychological deficits.

Investigated reported communalities in the perceptual impairments and body image distortions found after parietal lobe lesions and in schizophrenia. To compare these 2 syndromes, 15 patients with lesions of the parietal lobe and 15 patients with schizophrenia were tested on a neuropsychological battery designed to assess deficits in proprioception, tactile functions, and body image experience. Control groups consisted of 15 normal persons and of a series of 15 brain-injured cases in which the parietal lobe had been spared. Results indicate that both schizophrenic and parietally damaged Ss showed significant impairments in weight-discrimination measures of proprioceptive acuity when compared to the control brain-injured and normal Ss. No significant differences among groups were found on a comparable tactile size-estimation task, but the group with parietal injury exhibited a significant deficit in tactile sensory perception on the Finger Agnosia Test. Only the schizophrenic group showed evidence of disturbed body image when reality factors of body dysfunction were taken into account in the brain-injured patients. It is concluded that persons with schizophrenia and parietal lobe damage share a deficit in proprioception that may be based on different neurological substrates leading to (a) tactile impairments in cases with parietal damage, and (b) body-image disturbance in schizophrenia. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Connectionism and human learning: Critique of Gluck and Bower (1988).

M. A. Gluck and G. H. Bower (see record 1989-00340-001) argued that their data supported a connectionist model of human learning. Their Ss judged the probabilities of two diseases, given a target symptom; these probabilities were in fact equal. Because one disease was more frequent than the other, the target symptom was a better predictor of the less frequent disease than of the other. The Ss rated the two probabilities as unequal. In addition, Gluck and Bower argued that a simple connectionist model would be able to simulate the judgment bias. They assumed that Ss estimated the probabilities of the two diseases across all trials on which the target symptom occurred, either alone or with other symptoms, rather than the probability of each disease given only the target symptom. In fact, it is possible that the Ss were estimating the latter, in which case the bias in probability judgments was justified. Last, even if the Ss were estimating the former, the connectionist model cannot account for the bias seen in the probability judgments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emotion recognition and social competence in chronic schizophrenia.

This study evaluated (a) whether chronic, medicated schizophrenia patients show deficits in emotion recognition compared to nonpatients, and (b) whether deficits in emotion recognition are related to poorer social competence. Two emotion recognition tests developed by S. L. Kerr and J. M. Neale (1993) and Benton's Test of Facial Recognition (A. Benton, M. VanAllen, K. Hamsher, & H. Levin, 1978) were given to patients with chronic schizophrenia and nonpatient controls. Patients' social skills, social adjustment, and symptomatology were assessed. Like Kerr and Neale's unmedicated patients, these patients performed worse than controls on both emotion recognition tests and the control test. For patients, facial perception was related to the chronicity of illness and social competence. Chronicity of illness may contribute to face perception deficits in schizophrenia, which may affect social competence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modification of glassy carbon surfaces with synthetic laminin-derived peptides for nerve cell attachment and neurite growth

Working memory and its contribution to performance on strategic memory tests in schizophrenia were studied. Patients (n = 18) and control participants (n = 15), all men, received tests of immediate memory (forward digit span), working memory (listening, computation, and backward digit span), and long-term strategic (free recall, temporal order, and self-ordered pointing) and nonstrategic (recognition) memory. Schizophrenia patients performed worse on all tests. Education, verbal intelligence, and immediate memory capacity did not account for deficits in working memory in schizophrenia patients. Reduced working memory capacity accounted for group differences in strategic memory but not in recognition memory. Working memory impairment may be central to the profile of impaired cognitive performance in schizophrenia and is consistent with hypothesized frontal lobe dysfunction associated with this disease. Additional medial-temporal dysfunction may account for the recognition memory deficit.     

Everyday action in schizophrenia: Performance patterns and underlying cognitive mechanisms.

Everyday action is impaired among individuals with schizophrenia, yet few studies have characterized the nature of this deficit using performance-based measures. This study examined the performance of 20 individuals with schizophrenia or schizoaffective disorder on the Naturalistic Action Test (M. F. Schwartz, L. J. Buxbaum, M. Ferraro, T. Veramonti, & M. Segal, 2003). Performance was coded to examine overall impairment, task accomplishment, and error patterns and was compared with that of healthy controls (n = 28) and individuals with mild dementia (n = 23). Additionally, 2 competing accounts of everyday action deficits, the resource theory and an executive account, were evaluated. When compared with controls, the participants with schizophrenia demonstrated impaired performance. Relative to dementia patients, participants with schizophrenia obtained higher accomplishment scores but committed comparable rates of errors. Moreover, distributions of error types for the 2 groups differed, with the participants with schizophrenia demonstrating greater proportions of errors associated with executive dysfunction. This is the 1st study to show different Naturalistic Action Test performance patterns between 2 neurologically impaired populations. The distinct performance pattern demonstrated by individuals with schizophrenia reflects specific deficits in executive function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

In support of rational conceptualizations of schizophrenia.

Comments that E. Zigler and M. Glick (see record 1988-23546-001) in their article on paranoid schizophrenia and depression, in attempting to remove "paranoid schizophrenia" from schizophrenia, ignored, misinterpreted, and failed to recognize a substantial research base bearing on the definition of schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A review of neuropsychological differences between paranoid and nonparanoid schizophrenia patients

This review examines the literature on neuropsychological differences between paranoid and nonparanoid schizophrenia subjects. Thirty-two studies related to intellectual functioning, attention, memory, language, visual-spatial, and motor functions are discussed. Subjects with paranoid schizophrenia did not demonstrate higher intellectual functioning than those with nonparanoid schizophrenia, and both groups performed similarly on tests of verbal ability and visual-spatial functions. Several studies suggest that the paranoid subtype is associated with higher performance on tests of executive functions, attention, memory, and motor skills. However, the findings are inconsistent. Methodological issues in the literature are examined, including varying degrees of participants' chronicity and severity of illness among studies, criteria for diagnostic group membership, medication effects, reliability and validity of the neuropsychological measures, and statistical power.     

Therapy for metastatic melanoma: effective combination of dacarbazine, carmustine, cisplatin and tamoxifen

Violence in the workplace is sometimes a manifestation of an untreated psychiatric disorder. Paranoid personality disorder, paranoid schizophrenia, and delusional (paranoid) disorder are three psychiatric syndromes in which paranoid ideation is a prominent feature. While the vast majority of people with these conditions are not violent, paranoid workers can exhibit violent behavior as a reaction to beliefs that co-workers or supervisors are threatening or persecuting them. Three cases are described to illustrate the clinical presentation of these disorders and their management in an occupational setting.     

Encoding and retrieval processes in velo-cardio-facial syndrome (VCFS).

Velo-cardio-facial syndrome (VCFS) is a neurogenetic disorder associated with very high risk for developing schizophrenia. More than half of affected individuals experience transient psychotic symptoms during childhood and a third may develop schizophrenia. Memory regulation deficits disturbing both the encoding and retrieval stages of memory represent core deficits in the cognitive profile associated with schizophrenia. In this study, the authors investigate memory regulation processes in 33 individuals with VCFS along with 33 age- and sex-matched control participants. By using a directed forgetting paradigm and a continuous recognition paradigm, the authors examined selective encoding and suppression of irrelevant contents during retrieval in VCFS. Group comparison analyses revealed comparable performances on selective encoding and recognition accuracy between the VCFS group and control group. However, individuals with VCFS were more likely to make false recognitions and showed deficits in the suppression of irrelevant contents. Results suggest that trait-like deficits of memory regulation in VCFS can be observed during the retrieval stage, while selective encoding remains efficient. Memory regulation processes during retrieval may constitute a trait deficit in the memory profile of individuals with VCFS and may contribute to the cognitive deficits underlying an increased risk for developing schizophrenia in this population. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Paranoid schizophrenia: non-specificity of neuropsychological vulnerability markers

During stages of remission, patients with paranoid schizophrenia seldom show severe attentional or information-processing dysfunctions, except in cases of long-term chronicity. The diagnostic specificity of four putative psychological vulnerability indicators of schizophrenia - the Span of Apprehension, the degraded stimulus Continuous Performance Test (dsCPT), the degraded stimulus visual backward masking task and the Wisconsin Card Sorting Test (WCST) - was examined in a group of patients with paranoid schizophrenia. Since no single test seems to identify all patients, the use of a combination of measures may be a useful strategy. Accordingly, the four tests were administered to 18 paranoid schizophrenic patients, 18 depressed patients and 18 normal subjects. Paranoid schizophrenic patients could be distinguished from normal subjects primarily on the basis of their performance on the backward masking task and secondarily by the dsCPT and the WCST. Paranoid schizophrenic and depressed patients could be differentiated to some extent by their performance on an information-mask condition of the backward masking task. Thus, of the four measures studied, only the degraded stimulus backward masking appeared to be a specific indicator of paranoid schizophrenia.     

Understanding normal and impaired word reading: Computational principles in quasi-regular domains.

A connectionist approach to processing in quasi-regular domains, as exemplified by English word reading, is developed. Networks using appropriately structured orthographic and phonological representations were trained to read both regular and exception words, and yet were also able to read pronounceable nonwords as well as skilled readers. A mathematical analysis of a simplified system clarifies the close relationship of word frequency and spelling–sound consistency in influencing naming latencies. These insights were verified in subsequent simulations, including an attractor network that accounted for latency data directly in its time to settle on a response. Further analyses of the ability of networks to reproduce data on acquired surface dyslexia support a view of the reading system that incorporates a graded division of labor between semantic and phonological processes, and contrasts in important ways with the standard dual-route account. (PsycINFO Database Record (c) 2010 APA, all rights reserved)