عوامل موثر بر جنبه های مختلف نتایج روزمره در اسکیزوفرنی: نقش علائم منفی، شناخت، و ظرفیت عملکردی
|کد مقاله||سال انتشار||مقاله انگلیسی||ترجمه فارسی||تعداد کلمات|
|30254||2015||7 صفحه PDF||سفارش دهید||6838 کلمه|
Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)
Journal : Schizophrenia Research, Available online 11 April 2015
Cognition, negative symptoms, and depression are potential predictors of disability in schizophrenia. We present analyses of pooled data from four separate studies (all n > 169; total n = 821) that assessed differential aspects of disability and their potential determinants. We hypothesized that negative symptoms would predict social outcomes, but not vocational functioning or everyday activities and that cognition and functional capacity would predict vocational functioning and everyday activities but not social outcomes. The samples were rated by clinician informants for their everyday functioning in domains of social and vocational outcomes, and everyday activities, examined with assessments of cognition and functional capacity, rated clinically with the Positive and Negative Syndrome Scale (PANSS) and self-reporting depression. We computed a model that tested the hypotheses described above and compared it to a model that predicted that negative symptoms, depression, cognition, and functional capacity had equivalent influences on all aspects of everyday functioning. The former, specific relationship model fit the data adequately and we subsequently confirmed a similar fit within all four samples. Analyses of the relative goodness of fit suggested that this specific model fit the data better than the more general, equivalent influence predictor model. We suggest that treatments aimed at cognition may not affect social functioning as much as other aspects of disability, a finding consistent with earlier research on the treatment of cognitive deficits in schizophrenia, while negative symptoms predicted social functioning. These relationships are central features of schizophrenia and treatment efforts should be aimed accordingly.
Everyday functioning is commonly impaired in schizophrenia, affecting domains of social functioning, vocational performance, and performance of everyday activities. Even among those patients classified as ‘responders’ to available pharmacological and psychosocial treatments, disability rates are high and functional outcomes have changed minimally compared to success in treating psychosis (Hegarty et al., 1994). Cognitive deficits and negative symptoms are thought to represent the main drivers of disability, (Breier et al., 1991 and Carone et al., 1991) although influences outside of the individual such as opportunities and disincentives such as disability compensation meaningfully affect certain domains of functioning (Rosenheck et al., 2006 and Harvey et al., 2009). While positive symptoms usually improve with treatment, or can otherwise be compensated for (Ventura et al., 2009) both cognitive deficits and negative symptoms receive minimal benefit despite the fact that current antipsychotics control psychosis to the point that clinical remission rates are close to 50% in some studies (Harvey and Bellack, 2009). Moreover, negative and cognitive symptoms of schizophrenia, often present prior to the emergence of frank psychosis (Meyer et al., 2013), appear to be related but separable domains with different functional implications (Harvey et al., 2006 and Couture et al., 2011). Ventura et al. (2009) concur that cognitive and negative symptoms both predict outcome, but note that negative symptoms partially mediate the longitudinal relationship between cognition and outcome, and suggest therefore that cognition has both direct and indirect effects on functioning. Similarly, Lin et al. (2013) suggest that negative symptoms mediate the influence of cognition on outcome. Some of our own work has suggested that different domains of everyday functioning may not be as highly intercorrelated as previously thought and may also have different potential determinants. For instance, we previously reported that cognitive and functional capacity deficits predicted impairments in everyday activities (with the exception of social outcomes) and that negative symptoms were related to poor social outcomes to a greater extent than to other aspects of everyday outcome (Leifker et al., 2009). Meta-analyses have suggested that non-social cognitive deficits show less relation to social deficits when compared to the influence of social cognition (Green et al., 2000, Green et al., 2004 and Fett et al., 2011), and we have found that social deficits were less responsive to interventions aimed at treatment of cognition and functional skills deficits compared to work and instrumental functions (Bowie et al., 2012). Finally, achievement of different functional milestones (work, residence, and social achievements) is minimally intercorrelated in schizophrenia, suggesting that global indices of disability may lack the requisite specificity (Harvey et al., 2012) and that there are likely specific predictors of impairments in different domains of everyday functioning. In this paper we present analyses of a unique set of data: four separately collected datasets with similar methodological strategies that allowed for the evaluation of the relationship between three different aspects of real-world functional outcomes: social functioning, vocational skills, and performance of everyday activities, assessed with the same scales and informant strategies, and an identical set of potential determinants of functioning: neuropsychological test performance, performance-based measures of functional capacity, and negative and depressive symptoms. All four separate large-scale (n = 169 in the smallest; total n = 821) studies contribute information on the correlational relationships between everyday outcomes and an array of potential predictors. These studies were conducted in five separate geographical areas (New York, Atlanta, San Diego, Miami, and Dallas), have no overlap of patients or clinicians, and reflect a wide range of demographic and ethnic variation in the patients assessed, while the same real-world functional outcome measure, clinical ratings, self-reports of symptoms, and functional capacity measures were used. Cognition was assessed with batteries that have overlap of identical tests in 3/4 studies and a highly similar battery in the other study. While some results regarding correlational aspects between symptoms, functional capacity, and everyday outcomes have been published from three of the studies (see below), there has never been a systematic comparison of the influences of negative symptoms, depression, cognition, and functional capacity on everyday functioning across sequentially completed studies with the same assessment strategies. Based on previous research delineated above, we hypothesized that negative symptoms would predict social deficits, but not impairments in everyday activities and vocational outcomes, while cognition and functional capacity would predict deficits in everyday activities and vocational outcomes, but not social outcomes. This is a cross-sectional hypothesis in a sample of relatively chronic patients. Previous research (Ventura et al., 2015) has found that negative symptoms early in the course of illness predict both social functioning and work/school functioning at a year after initial contact, suggesting that influences of reductions in motivation or emotional expression have broad impacts. However, in a sample where the illness is already fully developed, we hypothesized that negative symptoms would exert a greater influence on social outcomes than everyday activities. We also hypothesized that depression, negative symptoms, and cognition and functional would exert independent influences on the real-world outcomes of interest. We tested this model in the sample as a whole, as well as in each of the individual subsamples. We also computed a generic model, wherein cognition and functional capacity, depression, and negative symptoms were hypothesized to be equally important for the prediction of all elements of real-world outcomes in the database. We tested several hypotheses in these analyses of the substantive model and its comparator model: 1. A model specifying that negative symptoms will be have a more substantial predictive influence on social deficits than cognition or functional capacity will be the best fit to that data. 2. A model specifying that cognition and functional capacity will predict everyday activities and vocational outcomes more substantially than social outcomes will be the best fit to the data. 3. Depression will impact all aspects of functional outcomes.