Three cognitive factors measured at a stabilized baseline point predicted very well whether our participants with a recent first episode of schizophrenia returned to paid work or schooling within 9 months, accounting for 52% of the variance. These 3 factors reflect working memory, verbal memory and processing speed, and attention and early perceptual processing abilities, all of which typically show prominent deficits in the early course of schizophrenia.2,36
In addition to this very strong multivariate prediction of work outcome, several individual cognitive performance scores at baseline predicted work outcome with medium to large effect sizes, supporting the view that several cognitive deficits are good predictors of return to work or school following an initial psychotic episode.
The strength of the relationship between cognitive performance and functional outcome in this study is at the high end of those reported in some prior studies of patients with chronic schizophrenia.12,14–16
Thus, it appears that the mixed results of prior studies examining relationships between individual cognitive components and functional outcome in recent-onset schizophrenia17
might be attributable to particular features of individual studies rather than the early phase of schizophrenia per se. Features of the current study that may have aided detection of a strong relationship may include the relatively standardized treatment package offered to the participants, a reasonably wide range of cognitive predictors, and focus on an aspect of functional outcome (work/school functioning) that may particularly require neurocognitive abilities.
The current report focuses on cognitive factors in predicting work outcome in recent-onset schizophrenia, but the larger study from which these data are drawn examined several additional factors that are part of our conceptual model of influences on work functioning in recent-onset schizophrenia, as shown in . We readily acknowledge that non-cognitive factors also influence work functioning in schizophrenia and that neurocognitive factors may operate through various mediators, as has been explored in some recent studies of chronic schizophrenia.37,38
In addition, we did not include measures of social cognition in this study, which have been shown to have, if anything, stronger relationships to functional outcome than do neurocognitive measures14
and may partially mediate the relationships between neurocognition and functional outcome.39
Nevertheless, it is striking that neurocognitive measures predict return to work or school in the early phase of schizophrenia as well as shown here.
Conceptual Model Showing Possible Factors Influencing Work Functioning in Recent-Onset Schizophrenic Disorders.
Limitations of the current study include the relatively small sample size, the lack of a standardized cognitive battery widely used to assess cognition in schizophrenia, and the absence of social cognition and functional capacity measures. We reduced the number of primary cognitive predictor variables to 3 to avoid chance findings, but a larger sample would allow greater statistical power to examine a wider range of cognitive predictors. We agree with the conclusion of Allott et al17
that inclusion of a widely used standardized cognitive battery intended for schizophrenia, such as the MATRICS Consensus Cognitive Battery,40
would allow improved comparison of results across such studies, but these data were collected before that battery had been developed. Subsequent studies would also benefit by examining possible mediators such as social cognition and functional capacity to clarify pathways of effects between neurocognition and work recovery in early psychosis. Thus, it would be very useful to determine the extent to which better neurocognitive functioning in the early course of illness directly leads to return to work or whether it contributes to other skills (eg, social competence, adaptive competence) that are in turn needed for successful transition into real-world work functioning, as recent models of predictive relationships within chronic schizophrenia and bipolar disorder have suggested.37,39
The present results certainly support the importance of finding effective ways to improve cognitive deficits in schizophrenia, a treatment target that has been increasingly recognized.41–43
Cognitive deficits appear to be strong rate-limiting factors in recovery of everyday functioning in the early phase of schizophrenia as well as in chronic schizophrenia. Many approaches to cognitive training have focused on different components of neurocognition and offer promise for significantly improving these core deficits of schizophrenia.44,45
Meta-analyses and a recent randomized trial with chronic schizophrenia patients suggest that cognitive training has stronger effects on work functioning if combined with active vocational rehabilitation approaches, such as supported employment.44–46
Supported employment and supported education approaches have recently started to be successfully applied in the initial period of schizophrenia to substantially increase rates of return to work or school,47–49
so the combination of cognitive training and supported employment/education seems like a very promising next early intervention step. Longitudinal predictive relationships such as those demonstrated in this study clearly support the view that improvements in neurocognition should increase functional capacity and functional outcome. Application of cognitive training and other cognition-enhancing interventions during the early phase of schizophrenia may be particularly promising, particularly if combined with supported employment/education because it may allow work recovery to occur before chronic disability develops.