Measurement of cognitive functions is an increasingly important goal for clinicians and researchers. Many neuropsychological test batteries are comprehensive and require specialized training to administer and interpret. The Trail Making Test is an accessible neuropsychological instrument that provides the examiner with information on a wide range of cognitive skills and can be completed in 5-10 min. Its background, psychometric properties, administration procedures and interpretive guidelines are provided in this protocol.

Real-world adaptive life skills are predicted by neuropsychological performance, symptoms, and functional capacity. Neuropsychological performance contributes little to the prediction of real-world performance after accounting for functional capacity. In some domains, negative and depressive symptoms influenced real-world performance while not relating to functional capacity or neuropsychological performance.

Differential predictors of functional competence and performance were found from discrete NP domains. Separating competence and performance provides a more precise perspective on correlates of disability. Changes in specific NP or functional skills might improve specific outcomes, rather than promoting global functional improvement.

OBJECTIVE Schizophrenia (SZ) and Bipolar Disorder (BD) are associated with multidimensional disability. This study examined differential predictors of functional deficits between the disorders. METHODS Community dwelling individuals with SZ (N=161) or BD (N=130) were administered neuropsychological tests, symptom measures, performance-based social and adaptive (i.e., everyday-living skills) functional competence measures, and rated on domains of real-world functioning: 1) Community and Household activities, 2) Work skills, and 3) Interpersonal relationships. We used confirmatory path analysis to find the best fitting models to examine the direct and indirect (as mediated by competence) prediction of the three domains of real-world functioning. RESULTS In all models for both groups, neurocognition’s relationship with outcomes was largely mediated by competence. Symptoms were negatively associated with outcomes but unassociated with competence, with the exception of depression, which was a direct and mediated (through social competence) predictor in BD. In both groups, neurocognition was related to Activities directly and through a mediated relationship with adaptive competence. Work Skills were directly and indirectly (through mediation with social competence) predicted by neurocognition in SZ and entirely mediated by adaptive and social competence in BD. Neurocognition was associated with Interpersonal Relationships directly in the SZ group, and mediated by social competence in both groups. CONCLUSIONS Although there was greater disability in SZ, neurocognition predicted worse functioning in all outcome domains in both disorders. Our study supports the shared role of neurocognition in BD and SZ in producing disability, with predictive differences between disorders observed in domain-specific effects of symptoms and social and adaptive competence.

Evidence suggests that differences in NP performance between schizophrenia and psychotic affective disorders are largely quantitative. NP impairment is also common in psychotic affective disorders. A significant minority of schizophrenia patients are NP normal.

Abstract:Cognitive dysfunction is a core feature of schizophrenia. Deficits are moderate to severe across several domains, including attention, working memory, verbal learning and memory, and executive functions. These deficits pre-date the onset of frank psychosis and are stable throughout the course of the illness in most patients. Over the past decade, the focus on these deficits has increased dramatically with the recognition that they are consistently the best predictor of functional outcomes across outcome domains and patient samples. Recent treatment studies, both pharmacological and behavioral, suggest that cognitive deficits are malleable. Other research calls into question the meaningfulness of cognitive change in schizophrenia. In this article, we review cognitive deficits in schizophrenia and focus on their treatment and relationship to functional outcome.

Negative symptoms and cognitive deficits in schizophrenia share many features and are correlated in their severity on a cross-sectional basis. The question arises as to the nature of this relationship: are these symptoms the same, caused by the same factor (or factors); or is the nature of their relationship determined by other factors, such as definitional issues and common correlates? In this article we provide a conceptual overview for addressing this question and provide a selective review of the literature on the cross-sectional and longitudinal relationships between these two features of the illness. We describe 4 different models of the "true" relationship between these variables. Some data suggest that the relationship between these variables is determined by the definition of negative symptoms employed and that, in general, the correlation is moderate at the most. Further, path modeling suggests the possibility, to be addressed with later research, that correlations between negative and cognitive symptoms and everyday functional outcomes may influence the observed correlations between these variables. Thus, we conclude that negative and cognitive symptoms may be separable, if not conceptually independent, domains of the illness and that it might be possible to develop treatments that target negative symptoms and cognitive deficits independently.

With new treatments targeting features of schizophrenia associated with functional disability, there is a need to evaluate the validity of ratings of everyday outcomes. It is unknown whether patients can validly self-report on aspects of their functional status, which would be a potentially economical method for obtaining outcome data. In this study, 67 older schizophrenia outpatients provided self-ratings of everyday real-world functioning using the specific levels of functioning scale (SLOF). They were also administered assessments of neuropsychological performance, performance-based measures of functional capacity and social skills, clinical symptoms, and quality of life. Case managers, unaware of other ratings, also generated SLOF ratings. Based on discrepancy scores, participants were categorized as accurate raters (n = 24), underestimators (n = 16), or overestimators (n = 27) of their functional status as compared to case managers' ratings. Patients' self-rated functional status was correlated with their subjective quality of life, but remarkably unassociated with case manager ratings of functional status or their own performance on functional capacity or social skills measures. Case manager ratings, however, were highly correlated with performance on functional capacity and social skills measures. Patients who underestimated their real world performance had better cognitive skills and greater self-rated depression than those who overestimated. Accurate raters demonstrated greater social skills than both overestimators and underestimators, while overestimators were most cognitively and functionally impaired. Accurate ratings of everyday outcomes in schizophrenia may require systematic observation of real world outcomes or performance-based measures, as self-reports were inconsistent with objective information.