Cognitive functioning has been found to be a predictor of functional outcome of schizophrenia. It is unclear, however, whether clinical recovery can be predicted by scores on specific cognitive domains. The predictive value of specific neurocognitive domains and other clinical variables for symptomatic and functional outcome and clinical recovery after a 2-year follow-up is explored in a group of 51 patients with non-affective first-episode psychosis. A comprehensive neurocognitive battery was administered 18 and 41 weeks after inclusion. Other patient characteristics, which were expected to independently predict clinical recovery, were assessed at baseline. Several neurocognitive tests, especially tests measuring speed of processing, and among others, Duration of Untreated Psychosis (DUP), were significant predictors of clinical recovery. Poor neuropsychological performance accurately predicted non-recovery, but improved neuropsychological performance did not accurately predict recovery. This study confirms previous findings of an association between neurocognition and outcome, but the results also suggest that in order to accurately predict recovery, the role of other factors needs to be investigated.
Schizophrenia is a disabling psychiatric disorder in which neurocognitive defects are common (Heinrichs and Zakzanis, 1998).Negative and positive symptoms are core features of the disorder according to current classification systems such as the Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV). Although disturbance in neurocognition is not incorporated in these classification systems, cognitive functioning has been found to be related to functional outcome of the disorder in cross-sectional studies in chronic patients (Green et al., 2002) and in longitudinal studies in chronic and first episode patients (Green et al., 2004, Robinson et al., 2004, Milev et al., 2005, Holthausen et al., 2007 and Gonzalez-Blanch et al., 2010). However, the relationship between neurocognitive defects and long-term functional outcome is not evident. The data do not clarify whether any, and if so, which cognitive domains predict functional outcome (Nuechterlein et al., 2008). An additional problem is the definition of functional outcome, which is a broad and multifaceted concept. Consequently, there is a need for standardized criteria for functional outcome that can be reliably assessed.
In this study, clinical recovery was defined as the combination of both symptomatic and functional remissions, sustained during a certain time frame, according to the criteria proposed by Wunderink et al. (2009). In short, the criteria for symptomatic remission were adopted from Andreasen et al. (2005), incorporating a selection of items from the Positive and Negative Syndrome Scale (PANSS) (Kay et al., 1987) with an observational period of the last 9 months of a 2-year follow-up period. Functional remission was assessed with the use of the Groningen Social Disabilities Schedule (GSDS) (Wiersma et al., 1990), with the same time frame.
The predictive value of specific neurocognitive domains and clinical variables for clinical recovery was explored in a group of patients with non-affective first-episode psychosis. First we investigated the extent to which symptomatic remission and functional remission were associated with achieving clinical recovery and the extent to which symptomatic remission was associated with functional remission.
Secondly, we investigated whether clinically recovered and non-recovered patients differed at baseline in general psychopathological and sociodemographic characteristics, and whether they differed in neurocognitive performance 18 weeks and 41 weeks after inclusion (i.e. after achieving remission status). Based on these analyses, we then applied a binary logistic regression analysis to identify factors predicting clinical recovery.
Several studies show that although neurocognitive impairments in patients, relative to controls, seem to be stable after the onset of psychosis, neurocognitive performance improves over time, both in controls and in patients (Hoff et al., 1999 and Albus et al., 2006). This may be the result of practice effects (Goldberg et al., 2007), but in patients it may also be related to clinical recovery (either as a facilitator or as a result). We therefore additionally investigated whether a greater improvement in neuropsychological performance from the first to the second test is associated with a greater chance of clinical recovery
