Stimulus generalization and schizophrenia.

Paranoid and nonparanoid schizophrenics, on and off drugs, were compared with medical inpatients for stimulus-generalization responsivity. The stimuli were lines differing in length, and the response alternatives differed in amplitude. There were no significant differences in gradients of stimulus generalization among the groups. This finding opposes Mednick's original anxiety-drive theory of schizophrenia, especially his assumption that schizophrenics overgeneralize. The finding does not oppose Mednick's amended theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Delusional thinking and cognitive organization in schizophrenia.

A delusion can be conceptualized as a form of cognitive reorganization; according to this interpretation a delusion serves to integrate into a meaningful and acceptable whole data which otherwise would be anxiety provoking. On the assumption that the utilization of delusions is representative of a generalized cognitive technique for dealing with ambiguous inputs it was hypothesized that delusional schizophrenics should manifest a stronger tendency to integrate ambiguous stimuli in a laboratory situation than nondelusional schizophrenics. To test the hypothesis 24 delusional and 25 nondelusional schizophrenics were compared on the McGill Closure Test. The results supported the hypothesis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Direct measurement of differential cognitive deficit in acute schizophrenia.

This is a longitudinal study in which 11 standardized tests of cognitive function were administered to 20,000 normal Ss and at a later point in time readministered to those Ss of the original group (N=15) who became schizophrenic and were hospitalized. The tests were also readministered to part of the original group (N=40) who, at the same point in time, were still normal. The results, which revealed significant differential deficit on 5 of the measures, suggest that lack of motivation to reach out and actively manipulate stimuli or experience new learning produced the differences observed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Application of stochastic modeling to the assessment of group and individual differences in cognitive functioning.

This article begins with a guiding schema of relations among cognitive science, clinical science, and assessment technology. Emphasis is placed on stochastic modeling of cognitive processes. Basic models are adjusted so as to parsimoniously accommodate performance deviations occurring with psychopathology. Modified portions of models indicate functions affected by disorder, whereas portions remaining intact indicate spared functions. Findings from clinical cognitive science are applied to the individual case using Bayesian procedures. Methods are instantiated with respect to cognitive psychopathology of paranoid schizophrenia. The authors address observations and issues arising from this application, including integration of these methods with current assessment practices. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Schizophrenia and the immediacy mechanism.

The author comments on the article "The primacy of cognition in schizophrenia," by R. W. Heinrichs (see record 2005-03019-003) and states that to the pursuit of schizophrenic/normal differences, there is no end. Heinrichs used meta-analyses to argue persuasively for the primacy of cognition for this role. His conclusion not only elicited agreement from both researchers and practitioners, but it is supported by his quantitative estimate of those differences through the use of meta-analysis and the associated effect sizes. An interesting question is why cognitive behavior should be so effective in differentiating schizophrenia patients from normal persons. The current author believes one answer is that cognitive behavior involves complex stimulus control. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

SMS text messages as a prosthetic aid in the cognitive rehabilitation of schizophrenia.

Objective: To evaluate the efficacy of short message service (SMS) text messages as a compensatory aid to improve independence in individuals diagnosed with schizophrenia and cognitive deficits. Design: An ABA withdrawal single-case experimental design was used. Eight men diagnosed with schizophrenia took part in the study; all demonstrated memory or planning problems in everyday life. Results: Five participants completed the entire trial. Four were more successful in carrying out daily activities when receiving prompts, whereas 1 did not profit from the intervention. Conclusion: SMS text messages can be effective in compensating for cognitive impairment in some but not all individuals with schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How to fill a half-full glass: Emotion and schizophrenia.

The authors comment on the article "The primacy of cognition in schizophrenia," by R. W. Heinrichs (see record 2005-03019-003). They state that Heinrichs persuasively argued as to the primacy of cognition in schizophrenia by citing an impressive body of evidence in favor of the view that schizophrenia is a complex biobehavioral disorder that manifests itself primarily in cognition. His conclusion is something of an anticlimax. At the same time, however, he acknowledged that "the glass of evidence is half empty as well as half full" (Heinrichs, 2005, p. 238). That is to say, the symptoms that mark out schizophrenia--the hallucinations, delusions, and so forth--do not appear to map onto cognitive deficits, or at least they do not map onto those that are measured with traditional neuropsychological tests. To fill the other half of the glass, the authors propose that a focus on emotion (largely neglected in the target article) will be of crucial importance. Furthermore, they commend the methods of cognitive neuropsychiatry as being eminently suitable to guide this research. The authors briefly illustrate the value of this approach with reference to affective characteristics of hallucinations and cognitive-emotional interactions in source monitoring. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Identical neural risk factors predict cognitive deficit in dyslexia and schizophrenia.

In previous work, the authors found that an anatomical risk index created from the combination of 7 neuroanatomical measures predicted reading and oral language skills in individuals with learning disabilities. Individuals with small auditory brain structures and reduced asymmetry had more deficits than those with large structures and exaggerated asymmetry. In the present study, the same anatomical index predicted reading and other cognitive abilities in 45 individuals with chronic schizophrenia. The anatomical risk index was significantly associated with broad cognitive ability (Pearson r = .53, p     

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)     

Bifactor and item response theory analyses of interviewer report scales of cognitive impairment in schizophrenia.

A psychometric analysis of 2 interview-based measures of cognitive deficits was conducted: the 21-item Clinical Global Impression of Cognition in Schizophrenia (CGI-CogS; Ventura et al., 2008), and the 20-item Schizophrenia Cognition Rating Scale (SCoRS; Keefe et al., 2006), which were administered on 2 occasions to a sample of people with schizophrenia. Traditional psychometrics, bifactor analysis, and item response theory methods were used to explore item functioning and dimensionality and to compare instruments. Despite containing similar item content, responses to the CGI-CogS demonstrated superior psychometric properties (e.g., higher item intercorrelations, better spread of ratings across response categories) relative to the SCoRS. The authors argue that these differences arise mainly from the differential use of prompts and how the items are phrased and scored. Bifactor analysis demonstrated that although both measures capture a broad range of cognitive functioning (e.g., working memory, social cognition), the common variance on each is overwhelmingly explained by a single general factor. Item response theory analyses of the combined pool of 41 items showed that measurement precision is peaked in the mild to moderate range of cognitive impairment. Finally, simulated adaptive testing revealed that only about 10 to 12 items are necessary to achieve latent trait level estimates with reasonably small standard errors for most individuals. This suggests that these interview-based measures of cognitive deficits could be shortened without loss of measurement precision. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Visual filtering and focusing among persons with schizophrenia, major depressive disorder, and no psychiatry history.

Assessed filtering and the ability to narrow attentive focusing among 30 persons with schizophrenia (mean age 44 yrs), 14 persons with major depression (MDD; mean age 46 yrs), and 20 normal persons (mean age 46 yrs). Conditions varied with the presence of distracters and their proximity to a target, and the presence of a window cue used to facilitate filtering. Among both the persons with schizophrenia and those with no psychiatric history, RTs were longest with distracters located closest to targets, and performance was not related to the presence of the window. The performance of persons with MDD was adversely affected with distracters located closest to targets, and facilitated with the presence of the window. These findings are consistent with relatively intact filtering and focusing in schizophrenia, and a filtering deficiency in MDD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intrinsic motivation in schizophrenia: Relationships to cognitive function, depression, anxiety, and personality.

The goal of the current project was to assess subjective reports of intrinsic motivation and their relationship to cognitive function, mood, and personality in schizophrenia. The authors used the Motivational Trait Questionnaire to examine 3 components of intrinsic motivation (personal mastery, competitive excellence, motivation related to anxiety). They also examined fluid intelligence, context processing, and working memory, as well as self-reports of mood and personal traits related to motivation. Participants were 66 individuals with schizophrenia or schizoaffective disorder and 44 healthy controls. Self-reports of personal mastery and competitive excellence did not differ between controls and individuals with schizophrenia, though patients did report significantly higher motivation related to anxiety. Among controls, but not patients, self-reports of intrinsic motivation were strongly related to cognitive performance. In contrast, both controls and patients showed similar strong relationships between self-reports of intrinsic motivation and related measures of mood and personality. These results are not consistent with the hypothesis that motivational deficits in schizophrenia reflect impairments in intrinsic motivation. However, they do suggest that the normal relationship between self-reports of intrinsic motivation and cognitive function is disrupted in schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Word meaning and sexual identification in paranoid schizophrenics and anxiety neurotics.

From psychoanalytic theory it is reasoned that the paranoid schizophrenic is one who has not made an adequate identification with the parent of like sex; other theoretical formulations presuppose a lack of identification with either parent. To test which of these hypotheses is valid, Osgood's Semantic Differential was used as a measure of identification (as established by Lazowick, 1955). It was given to a sample of hospitalized paranoid schizophrenics, an outpatient VA mental hygiene clinic sample of anxiety neurotics, and 2 control groups, hopsitalized TB patients and working people. The results indicated that the paranoid schizophrenic showed lack of identification with either parent. To some extent, this was true of the identification pattern of the neurotic group, but the latter also showed confusion of identification. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Easier tasks can have higher processing loads: Task difficulty and cognitive resource limitations in schizophrenia.

A differential deficit on the more difficult of 2 cognitive tasks has been found in numerous studies of schizophrenia. Resource limitations, rather than impairments in particular cognitive abilities, can explain these findings. Researchers often match tasks for difficulty level (healthy participant performance) to rule out resource limitations. This assumes processing resource load can be estimated from task difficulty, which is not always the case. A direct measure of resource allocation is needed. In this study, pupillary responses were recorded to index resource allocation (greater dilation indicates greater allocation) during performance of the digit span distractibility task in participants with schizophrenia (n = 35) and nonpsychiatric participants (n = 35). Nonpsychiatric participants recalled significantly more digits in the distraction, relative to the neutral, condition but also showed significantly greater pupil dilation in the distraction condition. The psychometrically "easier" condition, therefore, had a higher processing load. Participants with schizophrenia showed greater impairment relative to nonpsychiatric participants in the distraction condition. This finding cannot be attributed to a deficit in distractibility, however, because poorer performance was found in the higher-load condition, so resource limitations cannot be ruled out. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The dot pattern expectancy task: Reliability and replication of deficits in schizophrenia.

The dot pattern expectancy (DPX) task was created to efficiently assess context-processing deficits in patients with schizophrenia. Three studies investigated the characteristics of the DPX relevant for clinical applications. To answer questions regarding the psychometric properties of the task, performance on this task was studied in 2 healthy samples. Acceptable reliability and internal consistency and retest reliability were found for most measures of context processing, but not for a difficulty control condition. These characteristics were also found in a suggested brief version (DPXbrf), which may be more practical for clinical purposes. In a 3rd study, schizophrenia patients showed a specific deficit in context processing, replicating previous findings. Findings of these studies indicated some promise for use of this task in measuring context processing and also identified characteristics of this task that need to be strengthened to increase reliability, feasibility, and single-subject interpretability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rat prefrontal dopamine and cognitive control: Impaired and enhanced conflict performance.

It has been proposed that the cognitive dysfunction observed in patients with schizophrenia reflects a failure in cognitive control, in particular an inability to use task-relevant information to guide behavior. Using a prefrontal-dependent task designed to reflect aspects of cue and response conflict seen in human cognitive paradigms, we examined the influence of prefrontal dopamine receptor manipulation on the contextual control of response conflict. Rats were trained on two biconditional discrimination tasks, one auditory and one visual, in two discriminably different contexts. At test, audiovisual compounds of these training stimuli were presented, in extinction, in each of the training contexts. These compounds were formed in such a way that the individual elements previously dictated different responses during training, termed incongruent trials. Studies have shown that rats use contextual information to disambiguate the conflicting information provided by incongruent compounds, responding in manner that is appropriate to the stimulus element that was trained in the test context. Direct infusion of the D1 receptor agonist SKF-38393 into the prelimbic cortex was found to modulate incongruent trial performance in a manner that was dependent upon baseline performance: animals in the low baseline group demonstrated improved incongruent performance following infusion of SKF-38393 into the prelimbic cortex. In contrast, high performers showed a reduction in accuracy during incongruent compounds. This paradigm provides a reliable framework for assessing the efficacy of preclinical agents in treating the cognitive impairments seen in frontal-related disorders such as schizophrenia. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Neurocognition in first-episode schizophrenia: A meta-analytic review.

Compromised neurocognition is a core feature of schizophrenia. Following Heinrichs and Zakzanis’s (1998) seminal meta-analysis of middle-aged and predominantly chronic schizophrenia samples, the aim of this study is to provide a meta-analysis of neurocognitive findings from 47 studies of first-episode (FE) schizophrenia published through October 2007. The meta-analysis uses 43 separate samples of 2,204 FE patients with a mean age of 25.5 and 2,775 largely age- and gender-matched control participants. FE samples demonstrated medium-to-large impairments across 10 neurocognitive domains (mean effect sizes from ?0.64 to ?1.20). Findings indicate that impairments are reliably and broadly present by the FE, approach or match the degree of deficit shown in well-established illness, and are maximal in immediate verbal memory and processing speed. Larger IQ impairments in the FE compared to the premorbid period, but comparable to later phases of illness suggests deterioration between premorbid and FE phases followed by deficit stability at the group level. Considerable heterogeneity of effect sizes across studies, however, underscores variability in manifestations of the illness and a need for improved reporting of sample characteristics to support moderator variable analyses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neuropsychological impairment in patients with schizophrenia and evidence of hyponatremia and polydipsia.

Patients with schizophrenia and water imbalance may represent a subset of patients with distinct pathophysiological abnormalities and susceptibility to cognitive impairment. Specifically, patients with polydipsia and hyponatremia have been shown to have smaller anterior hippocampal volumes, which are also associated with various impairments in neuroendocrine function. To determine whether abnormalities in patients with water imbalance extend to the cognitive realm, the present study evaluated neuropsychological functioning in three groups of patients with schizophrenia: polydipsic hyponatremic, polydipsic normonatremic, and nonpolydipsic normonatremic. Participants were administered cognitive tests assessing intelligence, attention, learning/memory (verbal, nonverbal, emotional), and facial discrimination. Hyponatremic patients showed poorer overall neuropsychological functioning relative to all other patients, and polydipsic normonatremic patients performed intermediate to the other two groups. Results indicate that patients with schizophrenia and polydipsia, and particularly those with hyponatremia, show prominent cognitive deficits relative to patients without water imbalance. The clinical, neuroendocrine, and cognitive abnormalities in these patients may arise from pathology within the anterior hippocampus and associated prefrontal/limbic brain regions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Commentary on two articles concerning generalized and specific cognitive deficits.

This is a commentary on essays in this journal issue by M. E. Strauss (see record 2001-17627-002) and R. A. Knight and S. A Silverstein (see record 2001-17627-003) on research methodology for studying cognitive deficits. Concentrating mostly on Knight and Silverstein's article, the authors review the psychometric issues in the matched-task design, analyze Knight and Silverstein's "process-oriented" objections to that design, and scrutinize their methods for studying cognitive deficits, examining 2 of their empirical studies as examples of those methods. (PsycINFO Database Record (c) 2010 APA, all rights reserved)