Innovations In Clinical Neuroscience

NOV-DEC 2017

A peer-reviewed, evidence-based journal for clinicians in the field of neuroscience

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21 ICNS INNOVATIONS IN CLINICAL NEUROSCIENCE November-December 2017 • Volume 14 • Number 11–12 O R I G I N A L R E S E A R C H For interpersonal functioning, the overall regression analysis was significant when the two PANSS negative symptoms factors were entered into the analysis [F (2,627)=75.99, p<0.001]. As can be seen in Table 2, the PANSS experience factor accounted for 21 percent of the variance, with the PANSS expression factor not entering the equation. When predicting everyday activities, the overall regression analysis was not significant [F (2,627)=1.03, p=0.36]. For the prediction of vocational activities, the overall analysis was significant, [F (2,627)=4.44, p<0.05]. The PANSS expression factor entered the equation and predicted one percent of the variance in vocational outcomes. When examining the overall negative symptoms factor, the pattern of significant and nonsignificant overall results was the same. As can be seen in Table 2, total negative symptoms predicted 19 percent of the variance in interpersonal functioning and three percent of the variance in vocational outcomes. In the next set of analyses, we added two other predictors, composite cognitive performance, and UPSA-B total scores, to the two negative symptom factors to predict the three SLOF subscales. For the prediction of interpersonal functioning, the overall analysis was significant [F (4,625)=37.45, p<0.001]. In the stepwise results, the PANSS experience factor again accounted for 21 percent of the variance in social outcomes, with UPSA-B scores adding one percent of the variance. When predicting everyday activities, the overall analysis was significant [F (4,625)=30.86, p<0.001]. As noted in Table 3, neither of the PANSS negative symptoms factors entered the equation, and the cognitive performance composite and UPSA-B scores combined to account for 12 percent of the variance in everyday activities. Finally, when predicting work functioning, the overall regression was again significant [F (4,625)=19.72, p<0.001]. UPSA-B scores and cognitive composite scores accounted for 10 percent of the variance in work outcomes, while the PANSS experience negative factor added an incremental one percent of variance. DISCUSSION A benefit of our approach in this study was the use of the two-factor negative symptom solution, rather than relying on single PANSS NSF items in the model. Reduced experience and reduced expression as negative symptom factors had clearly different patterns of prediction of everyday functioning. Social functioning appears to be related to experience-related negative symptoms, while expression-related symptoms showed no correlation. PANSS experience-related negative symptoms predicted social outcomes slightly more efficiently than total negative symptoms (PANSS NSF). In only one analysis was expression-related symptoms associated with functional outcomes, accounting for one percent of the variance in vocational outcomes. However, separation of negative symptoms into experience-related and expression-related components did not increase the cross-sectional predictability of activities and functioning by negative symptoms measures. There are implications with the use of the PANSS in the assessment of negative symptoms. Although the PANSS was not designed to separate reduced experience and reduced expression symptoms, these two factors seem to have clear discriminant validity in this study. This finding suggests that the PANSS can adequately serve as an assessment measure in trials with an eventual goal of improving social outcomes when separating the PANSS expressive-related and experience- related subfactors. Expression-related symptoms, although more apparently pathological and obvious, do not contribute to indices of disability in this study. Much like flagrant psychotic symptoms, obvious affective flattening appears to be less functionally significant than symptoms more related to motivational factors. Treatment efforts seem better directed toward experience- related symptoms, targeting increases in motivation. Limitations. The limitations of the study include its cross-sectional design and lack of attempt to stratify on the basis of negative symptom severity. Negative symptoms predict other outcomes longitudinally, particularly when the studies begin early in the course of illness. 29 As the goal of these analyses was to test the ability of the PANSS to define separable dimensions of negative symptoms, we made no attempt to perform additional negative symptoms assessments. Positive symptoms had already been shown to fail to predict any aspects of outcome in this large database. CONCLUSION In conclusion, a factor from the PANSS defined by three items was at least as efficient as the total negative symptom score in predicting everyday social outcomes and showed clear separation from symptoms of reduced expression in predicting impairment in social outcomes in people with schizophrenia. This delineation did not improve the prediction of other aspects of outcome, suggesting a reasonably specific correlation between social impairment and symptoms of reduced emotional experience as measured by the PANSS and associated motivational deficits in people with schizophrenia. TABLE 3. Regression results predicting everyday functioning with negative symptoms, cognition, and functional capacity SLOF VARIABLE STEP VARIABLE R 2 INCREMENTAL R 2 TOTAL t p Interpersonal functioning 1 Experience 0.21 0.21 11.78 0.001 2 UPSA-B total 0.01 0.22 2.81 0.005 Everyday activities 1 Cognitive composite 0.1 0.1 7.15 0.001 2 UPSA-B total 0.02 0.21 3.09 0.002 Vocational functioning 1 UPSA-B total 0.08 0.08 6.67 0.001 2 Cognitive composite 0.02 0.1 2.96 0.002 3 Experience 0.01 0.11 2.20 0.02 SLOF: specific levels of functioning; UPSA-B: University of California, San Diego Performance-based Skills Assessment-Brief

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