Morris D. Bell

Five-component model of schizophrenia: assessing the factorial invariance of the positive and negative syndrome scale.

A five-component model of schizophrenia has been presented by Kay and Sevy based upon an analysis of the Positive and Negative Syndrome Scale. Kay and Sevy found factorial validity for negative and positive syndromes, and they identified excitement, depressive, and cognitive components as well. They suggested that subtypes and syndromes can be mapped along dimensions presented in their model. The present study compares the five-component solution for a new sample of 146 subjects to a reanalysis of the Kay and Sevy data. Despite divergent demographic characteristics, the two samples produce similar dimensions. Correlations of component loadings and subject scores as well as confirmatory factor analysis are presented. Discussion focuses on points of agreement and important differences in the symptoms assigned to each component. How the dimensions relate to rationally derived models of positive and negative syndromes is reviewed, and implications for subtyping and other methods of examining the heterogeneity of schizophrenia are considered.

Sensory gating deficits during the mid-latency phase of information processing in medicated schizophrenia patients

Sensory gating during preattentive phases of information processing has been extensively examined. Sensory gating processes that occur during subsequent phases of information processing have not been fully examined. The relationship between P50 sensory gating and schizophrenia symptoms remains underspecified and the clinical correlates of N100 and P200 gating are yet to be examined. Sensory gating indices derived from the mid-latency auditory evoked responses during preattentive (P50) and attentive (N100, P200) phases of information processing were collected from schizophrenia patients who were stable and mainly being treated with atypical antipsychotic medications (n=23) and age- and gender-matched healthy control subjects (n=23). Schizophrenia patients had demonstrable habituation or sensory gating difficulties throughout the mid-latency range of information processing. Moreover, we found no correlations between P50-derived sensory gating indices and the amplitude or latency of the more attention-related P300 evoked response. A number of N100 and P200 gating measures correlated with P300 variables. Finally, we found no correlations between sensory gating indices and schizophrenia symptoms clusters. These results suggest that sensory gating is a pervasive abnormality in schizophrenia patients that is not limited to the preattentive phase of information processing. Furthermore, the data suggest that N100 and P200 gating indices may influence subsequent information processing.

Positive and negative affect recognition in schizophrenia: a comparison with substance abuse and normal control subjects

This study had three aims: to compare a schizophrenia sample (n = 50) with a substance abuse (n = 25) and normal sample (n = 81) on affect recognition; to compare differences in their performance between positive and negative affect recognition; and to introduce a new videotape method of stimulus presentation. Subjects were asked to identify the predominant affect depicted in 21 5-10-s vignettes containing three trials of seven affect states. Results demonstrate significant group differences: normal subjects scored in the normal or mild range, substance abuse (s/a) subjects scored in the mild and moderate ranges, and the schizophrenia sample scored predominantly in the moderate to severe ranges. Accuracies were 92.3% for the normal sample, 77.2 for the s/a sample and 64.8 for the schizophrenia sample. Response dispersions were 97.6% for the schizophrenia group, 69% for the s/a sample and 38% in the normal sample. A repeated measures ANOVA revealed a group by type of affect interaction with schizophrenia subjects showing far greater differential impairment on negative affect recognition. Difficulty of item did not contribute to this difference. Test-retest reliability at 5 months for this new method was r = 0.76, and stability of categorization was very high over 5 months (weighted kappa = 0.93). These affect recognition deficits in schizophrenia are discussed as they relate to lateralization of brain function, high EE families, social skills impairment and implications for rehabilitation services.

The positive and negative syndrome scale and the brief psychiatric rating scale : reliability, comparability, and predictive validity

In a psychiatric rehabilitation study, 154 concurrent ratings were performed using the 30-item Positive and Negative Syndrome Scale (PANSS) and the 18-item Brief Psychiatric Rating Scale (BPRS). Although both instruments had excellent interrater reliability, the PANSS was consistently better: on the 18 symptom items the two instruments share, the PANSS had higher intraclass rs on 14; for the syndromes, the PANSS was higher than the BPRS on positive, negative, and total. Weighted Kappas comparing shared items revealed that most were not interchangeable, with only three coefficients in the excellent range. However, syndrome scale scores were very highly correlated and resulted in similar classification for negative schizophrenia. Ten of the 12 items of the PANSS not included in the BPRS had low zero-order correlations with BPRS items, which suggests that they measure symptoms distinct from those measured by the BPRS and should add to clinical predictive power. This proved true in our study of rehabilitation of patients with schizophrenia PANSS symptom ratings explained up to 55% of the variance on seven measures of work performance, whereas the BPRS had lower predictive power on six of the seven measures. We concluded that the PANSS may be superior to the BPRS in clinical research on schizophrenia and that most BPRS items are not interchangeable with identically named PANSS items.

Theory of mind performance in schizophrenia: diagnostic, symptom, and neuropsychological correlates.

The purpose of this study was to explore the relationship between Theory of Mind (ToM) performance and schizophrenia subtype, symptom, and neuropsychological variables. One hundred twenty-eight stable outpatients with schizophrenia or schizoaffective disorder were assessed during the intake phase of a vocational and cognitive rehabilitation study. Results indicate that ToM performance differed significantly by schizophrenia diagnosis, with people diagnosed with disorganized schizophrenia performing the most poorly. Theory of Mind performance was also significantly correlated with measures of thought disorder and verbal memory. Regression analysis revealed that thought disorder and verbal memory measures explained 30% of the variance in ToM scores. Findings suggest that there is theory of mind variance in the schizophrenia population and theory of mind is strongly related to thought disorder, verbal memory, and cognitive disorganization. Contrary to previous reports, ToM was not related to measures of paranoia.

Neurocognition, Social Cognition, Perceived Social Discomfort, and Vocational Outcomes in Schizophrenia

Social cognition has been suggested to be an important mediating variable in the relationship between neurocognition and functional outcome. The present study tested this model in relation to work rehabilitation outcome and added self-reported social discomfort as a possible mediator. One hundred fifty-one participants with schizophrenia or schizoaffective disorder participated in a 26-week work therapy program. Neurocognition was constructed as a latent construct comprised of selected variables from our intake test battery representing executive functioning, verbal memory, attention and working memory, processing speed, and thought disorder. Social cognition at intake was the other latent construct comprised of variables representing affect recognition, theory of mind, self-reported egocentricity, and ratings of rapport. The 2 latent constructs received support from confirmatory factor analysis. Social discomfort on the job was based on their self-report on a weekly questionnaire. In addition, we constructed a composite rehabilitation outcome that was based on how many hours they worked, how well they worked, and how complex was the job that they were doing. Path analysis showed direct effects of neurocognition on rehabilitation outcome and indirect effects mediated by social cognition and social discomfort. This model proved to be a good fit to the data and far superior to another model where only social cognition was the mediating variable between neurocognition and rehabilitation outcome. Findings suggest that neurocognition affects social cognition and that poorer social cognition leads to social discomfort on the job, which in turn leads to poorer rehabilitation outcomes. Implications for rehabilitation interventions are discussed.

Review on vocational predictors: a systematic review of predictors of vocational outcomes among individuals with schizophrenia: an update since 1998

Objective: Predictors of employment outcomes of individuals with schizophrenia have continued to be studied over the past decade with implications for the development of vocational interventions to help the mentally ill get and keep jobs. Methods: A total of 62 relevant studies since 1998 were systematically reviewed by means of meta-analysis and frequency counts. Frequency count allowed all 62 studies to be included, whereas the meta-analysis excluded studies with inadequate information but made it possible to estimate the magnitude of effects. Results: Both methods resulted in similar findings. In contrast to an earlier review, cognitive functioning received overwhelming support as a significant predictor. Other significant predictors included education, negative symptoms, social support and skills, age, work history (previous history of successful employment), and rehabilitation service to restore community functioning and well-being by occupational therapists, psychiatrists, psychologists, social workers and other mental health professionals. Positive symptoms, substance abuse, gender and hospitalization history were found to be non-significant predictors. The frequency count did not support marital status as a significant predictor but the meta-analysis did. Conclusions: This review highlights increasing sophistication in understanding the links between individual characteristics and functional impairments. It also suggests that more research is needed into other potentially important predictors that may be changeable and relate to recovery. These include attitudes and beliefs about disability payments and psychological processes such as self-stigmatization, negative beliefs, and social skills deficits for which intervention may be possible.

Wisconsin Card Sorting Test and work performance in schizophrenia.

Patients with schizophrenia have long been observed to perform poorly on the Wisconsin Card Sorting Test (WCST). Although numerous studies have established links between WCST performance and specific and diffuse structural brain abnormalities, little is known about its relationship to occupational functioning. The present study has investigated the relationship between behavior at a vocational work placement and performance on the WCST test for 89 subjects with schizophrenia or schizoaffective disorder. Multiple regression analyses that examined select WCST raw scores and that covaried out IQ and Digit Symbol Subtest scores found that Task Orientation at work was significantly related to WCST Trials to the First Category and Total Number Correct. Multiple regression analyses that examined standard scores, corrected for age and education, revealed that Task Orientation was related to Percent Conceptual Level and that Social Skills were related to Total Errors and Percent Conceptual Level. Results support the criterion-related validity of the WCST and have implications for understanding impairments in work function.

Neurocognitive enhancement therapy with vocational services: Work outcomes at two-year follow-up

UNLABELLED Neurocognitive enhancement therapy (NET) is a remediation program for the persistent and function-limiting cognitive impairments of schizophrenia. In a previous study in veterans, NET improved work therapy outcomes as well as executive function and working memory. The present study aimed to determine whether NET could enhance functional outcomes among schizophrenia and schizoaffective patients in a community mental health center receiving community-based vocational services. METHOD Patients (N=72) participated in a hybrid transitional and supported employment program (VOC) and were randomized to either NET+VOC or VOC only. NET+VOC included computer-based cognitive training, work feedback and a social information information-processing group. VOC only also included two weekly support groups. Active intervention was 12 months with 12 month follow-up. Follow-up rate was 100%. RESULTS NET+VOC patients worked significantly more hours during the 12 month follow-up period, reached a significantly higher cumulative rate of competitive employment by the sixth quarter, and maintained significantly higher rates of employment. CONCLUSION NET training improved vocational outcomes, suggesting the value of combining cognitive remediation with other rehabilitation methods to enhance functional outcomes.

Initial and final work Performance in schizophrenia: Cognitive and symptom predictors

Studies have shown that cognitive functioning may limit the rate, tenure, and type of work performed by people with schizophrenia. The present study tested the hypothesis that cognitive abilities needed for initial improvement in work performance would differ from those needed in later vocational development. Ninety-six outpatients with schizophrenia or schizoaffective disorder who participated in a work rehabilitation program were administered neuropsychological testing at intake. Their work performance was evaluated biweekly for 26 weeks. Cognitive test variables were entered into regressions predicting the slope of individual performance curves from weeks 1 to 13 and 13 to 26. Neuropsychological variables accounted for 28% of the variance in slope during the initial period. The strongest predictor was a Continuous Performance Task variable that measures inattentiveness. Other important variables were measures of idiosyncratic thinking, cognitive flexibility, and verbal memory. Neuropsychological variables accounted for 19% of the variance in the slope during the final period. The strongest predictor was verbal learning, while measures of cognitive impulsivity and psychomotor functioning were also significant contributors. There was no relationship between work performance and symptoms for weeks 1 to 13 or 13 to 26. These findings suggest that while attention is more important for initial success, verbal memory becomes more important for sustained improvement. Remediating or accommodating such deficits in a time-sensitive fashion may be a necessary feature for successful rehabilitation.