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The concept of functional recovery transcends the traditional medical model of symptom remission (Andreasen et al., 2005) to include the attainment of meaningful roles in the CT99021 (Harvey & Bellack, 2009). As such, community functioning is an increasingly important treatment target for schizophrenia. Unfortunately, full functional recovery is rarely attained and even less frequently maintained, even after symptoms have remitted (Robinson et al., 1999; 2004). Profound impairments persist after clinical stabilization across multiple domains of functioning, including occupational and academic achievement, interpersonal relationships, and independent living (Abdallah et al., 2009; Bowie et al., 2008; Green et al., 2004).
Functioning can be considered to consist of two distinct constructs: competence (what one can do under optimal conditions) and performance (what one actually does in the real world; Gupta et al., 2012). Competence, typically indexed by performance on measures of various cognitive and functional abilities, accounts for a substantial, but still minority, portion of the variance in performance, typically indexed through ratings of community behavior by third-party observers. In a recent report, Gupta et al., (2012) examined this competence-performance discrepancy and found that both intrinsic (e.g., neurocognitive ability, depressive symptoms, motivation) and environmental (e.g., residential and vocational opportunities, hospitalization, disability rules) factors predict whether an individual under-performs in the real world relative to performance on laboratory measures of various functional and cognitive abilities.
Positive and negative symptoms have been consistently found to be minimally related to functional competence, but they are often found to be associated with poorer everyday real world performance even after other factors, such as functional competence, are considered (e.g., Bowie et al., 2006; 2008; 2010; Leifker et al., 2009; Sabbag et al., 2012; Smith et al., 2002; Stefanopoulou et al., 2011). Positive symptoms tend to respond well to pharmaceutical treatment, but approximately 15-20% of people with schizophrenia experience treatment-resistant negative symptoms (Buchanan, 2007) that are strongly associated with poor functional outcomes (e.g., Herberner & Harrow, 2004; Leifker et al., 2009; Milev et al., 2005; Sabbag et al., 2012). Depressive symptoms are also important to consider in schizophrenia, and are present in up to 83% of patients at first admission for schizophrenia (Häfner et al., 2005), 40% meeting lifetime criteria for major depression (Harvey et al., in press), and in any month approximately 35% of patients with schizophrenia present with at least one of the core symptoms of depression (an der Heiden et al., 2005). Patients in the community still experience symptoms of depression, even after remission of positive symptoms (Baynes et al., 2000; Pogue-Geile, 1989). These residual depressive symptoms are overlooked in schizophrenia, yet they may interfere with everyday task performance (Bowie et al., 2006; 2008; 2010; Harvey, 2011; Sabbag et al., 2012). Thus, negative and depressive symptoms provide insight into persistent functional impairment in spite of positive symptom reduction. Although negative symptoms are well known to be associated with functional disability, depressive symptoms in schizophrenia have not yet received much attention in the research literature.
Results from this study suggest that specific classes of prominent symptoms moderate the relationship between functional competence at baseline and functional performance at an 18month follow-up for both adaptive and interpersonal functioning in individuals with schizophrenia. No moderation was observed for the relationship between neurocognition and capacity or performance. A relationship existed between competence and performance for individuals with primarily positive symptoms and undifferentiated symptoms, such that greater competence in an optimized assessment setting was associated with better future real world performance. No significant relationship was found between baseline competence and real world performance 18months later for individuals with primarily negative or primarily depressive symptoms.