Predictors of current functioning and functional decline in schizophrenia

Abstract

Positive, negative, and cognitive symptoms of schizophrenia may affect functional outcomes. However, these factors alone do not account for a large percentage of variance in outcomes. We investigated demographic, cognitive, symptom, and functional capacity predictors of current functional status in 280 outpatients with schizophrenia or schizoaffective disorder. Functional decline over the lifespan was also examined in a subset of participants. Stepwise regressions modeled predictors of current functional status and functional decline as measured by the Assessment of Lifespan Functioning Attainment (ALFA). ALFA functional domains included paid employment, independence in living situation, romantic relationships, close friendships, and recreational engagement. More severe depressive symptoms were consistently associated with worse current community integration (lower levels of close friendships and recreational engagement). Better working memory performance was associated with higher rates of current paid employment. There were no consistent modifiable predictors of decline in functioning, but women reported less functional decline in the domains of employment and close friendships than men. Better cognitive performance was associated with less decline in living independence and romantic relationships, but more decline in paid employment and recreational engagement. Increased assessment and treatment of comorbid depressive symptoms may improve functional outcomes in people with schizophrenia.

Introduction

Schizophrenia is now largely considered to be a group of syndromes, rather than a single illness, due to significant genetic (Sebat et al., 2009, Stefansson et al., 2008, Walsh et al., 2008), symptom (Carpenter and Buchanan, 1994, Liddle and Morris, 1991, Wagman, 1988), and social risk factor (Cantor-Graae and Selten, 2005, Janssen et al., 2004, Zammit et al., 2004) heterogeneity. While different factors are associated with the various syndromes (Liddle, 1987, Liddle et al., 1992, Silverstein et al., 2000, Williams et al., 2000), schizophrenia spectrum disorders consistently lead to poor functional outcomes across multiple domains, including employment, living independence, and social functioning (Green et al., 2000, Green et al., 2004, Harvey et al., 1998).

Currently validated measures of real world functioning (Leifker et al., 2011) only consider a snapshot in time and do not provide a comprehensive lifespan perspective for outcomes relevant to schizophrenia. In addition, the factors predicting current functional status may be different from predictors of functional decline. Moreover, the factors associated with functional outcomes vary greatly (Barnes et al., 2008, Kolakowska et al., 1985, Marwaha and Johnson, 2004, Milev et al., 2005, Sabbag et al., 2012, Wölwer et al., 2014). Therefore, improved characterization of the set of factors that moderate functional outcomes in schizophrenia may be useful in developing and targeting treatments.

Studies of lifespan functioning in schizophrenia are very few and have been limited primarily to investigations of neurocognitive impairment (Friedman et al., 2001, Kalache et al., 2014, Kurtz, 2005) or qualitative assessments (Shepherd et al., 2012). A new scale, the Assessment of Lifespan Functioning Attainment (ALFA; Joseph et al., 2015), enables the quantitative assessment of various stages in lifespan functioning including current status and post-psychosis decline for five different functional domains: paid employment, living independence, romantic relationships, close friendships, and recreational engagement.

The aim of this study was to model predictors of current functional status and post-psychosis functional decline using the ALFA scale in a large sample of individuals with schizophrenia-spectrum disorders. We predicted that demographic, illness burden, cognitive, and functional capacity factors would account for a significant amount of variance in functional outcomes.