This study examined the relationships between neurocognition, social cognition, and initial functional level and the rates of functional rehabilitative change in community-based psychosocial rehabilitation interventions for individuals diagnosed with schizophrenia. We also tested a moderator hypothesis about service intensity. These findings have relevance to our understanding of the heterogeneity in functional rehabilitative outcomes, to our understanding of the conditions of rehabilitative change, and for the design of psychosocial interventions in the community.
Our first finding was that the initial level of psychosocial functioning was related to both social cognition and neurocognition at baseline. This cross-sectional finding corroborates a large body of literature showing that better neurocognition is associated with higher levels of psychosocial functioning in schizophrenia across a range of settings and outcomes.55
There is much less research on social cognition, but this finding corroborates those few studies as well.23
The effect size for social cognition was in the medium range, and for neurocognition, it was near the medium range. The magnitude of the effects are notable given that it has been argued that the impact of neurocognitive and social cognitive factors will attenuate as the outcomes become closer to real world functioning which is what was measured in this study21,23
. These findings further establish the ecological validity of the impact of neurocognition and social cognition on functional status and support notions that both capacities underlay successful functioning in the community for individuals diagnosed with schizophrenia. Cross-sectional relationships, however, do not suggest that any factor will actually influence rates of change in desired outcomes during an intervention. Change rate was the focus of the second study hypothesis.
While change in functional outcome is not consistently achieved in randomized studies of community-based psychosocial interventions for schizophrenia, when they do occur, there is large between-individual heterogeneity in the occurrence and rates of change in even the most effective interventions.2–14
The present findings suggest that when significant rehabilitative change occurs, pretreatment levels of neurocognition and social cognition both significantly influence the rate of functional rehabilitative change over 12 months. Specifically, higher neurocognition and social cognition scores at baseline predicted higher rates of functional change over the subsequent 12 months. This suggests that these are rate-limiting factors for rehabilitative change and must be considered when understanding the factors responsible for promoting change in psychosocial rehabilitation, and, further, that they offer one explanation for the wide heterogeneity in functional change for individuals who participate in effective community-based interventions. This study also provides support for the ecological validity of the relationship between neurocognition and functional rehabilitative change. While previous studies have identified neurocognition as a rate-limiting factor for aspects of behavioral change in the hospital, this influence has rarely been examined in the community-based contexts where most rehabilitation occurs.
Our findings on social cognition are the first to establish it as a rate-limiting factor for rehabilitative change. This suggests that better social cognition is important to improving rates of functional rehabilitative change in community-based interventions. In a previous study,19
neurocognition and social cognition combined in a causal model to influence community-based psychosocial functioning. Our present findings suggest that understanding how these factors interact in treatment to influence rehabilitative change could be a useful line of research.
We also found that greater service intensity was related to higher rates of improvement in functional outcome over time. This finding replicates earlier studies28,29
and lays the foundation for examining whether service intensity moderates the relationships between neurocognition and functional outcome, and social cognition and functional outcome.
Once a rate-limiting factor like neurocognition or social cognition is identified, it is important to understand the conditions under which it exerts its influence and also the degree to which the existing interventions can be altered to influence its impact. One of these moderating conditions is the character of the services delivered and, in particular, the intensity of service that has been suggested as a moderator of the rate-limiting influence of neurocognition.20
We tested for 2 possible moderating dynamics. Our results offered some limited support for the compensatory hypothesis where higher service intensity will be associated with a weaker relationship between baseline neurocognition, social cognition, and subsequent functional outcome. First, the relationship between neurocognition and initial functional status is weaker for individuals who had more subsequent days of treatment. This could be because individuals self-select into fewer treatment days when they experience greater rate-limiting impacts or practitioners decrease the intensity of their services when this relationship is palpable to them. Second, there was a trend (P
= .06) for more treatment days to be associated with a weaker influence of social cognition on rehabilitative change. This has more direct relevance to our moderator hypothesis and could suggest that increased practitioner activity reflected in more days of treatment compensates or overrides the rate-limiting impact of social cognition on functional change. Further research is needed to understand the conditions that facilitate the integration of neurocognition and social cognition and how treatment variables and rate-limiting variables interact.56
Overall, our results suggest that neurocognition and social cognition influence the initial functional level and the rates of rehabilitative change and that models of community-based psychosocial rehabilitation need to begin to integrate these factors into their services in several ways. First, practitioners and consumers could benefit from understanding that these factors do impact rates of functional rehabilitative change and that service factors alone cannot account for the individual heterogeneity in treatment outcomes. Second, this knowledge could be used as a foundation for service activities. For example, with relevant assessment, these factors could be used to identify individuals for whom functional change might be easier or more challenging. This can be used to educate both consumers and practitioners so that interventions can be more individually tailored and realistic change goals can be set. Rather than being used to delimit the rates of possible functional change, these assessments can be used to maximize individual change rates by minimizing practitioner and consumer frustration due to inaccurate goal setting and inappropriately low or high expectations for change. Third, there are psychosocial interventions available that are designed to compensate for neuropsychological deficits that have shown effectiveness in improving functional outcomes. Errorless learning57
and Cognitive Adaptation Training58
are central examples. Strategies for transporting and integrating these interventions into existing community-based rehabilitation services are needed.
Another issue with rate-limiting factors is whether they can be directly improved through treatment or intervention. In addition to compensatory interventions that are designed to take cognitive deficits into account, restorative interventions such as cognitive remediation are designed to improve underlying cognitive functions. Such approaches use systematically graded cognitive exercises and have shown some success in improving basic cognitive functions in the serious mentally ill.59,60
In combination with other psychosocial interventions, cognitive interventions have yielded improved processing of social information.56,61
Cognitive remediation approaches are complementary to psychopharmacological approaches intended to identify and evaluate potential cognition-enhancing drugs for schizophrenia and other major mental illnesses, as illustrated by the National Institute of Mental Health-Measurement and Treatment Research to Improve Cognition in Schizophrenia Initiative.55,62
Two recent studies on vocational intervention have shown that modest cognitive change is possible from remediation approaches and that combining cognitive remediation with psychosocial interventions is more effective in improving vocational outcomes than psychosocial intervention alone.20,60
However, it is not yet clear to what degree cognitive change is linked to treatment effects. This is a critical question for future experimental and observational studies.
Concerning social cognition, it is not yet clear whether compensatory or remediation strategies are best suited. There is early work suggesting that some aspects of social cognition respond to remediation strategies.63
It is clear, however, that social cognition must be a topic of investigation in terms of rehabilitation interventions, much as was begun with neurocognition over a decade ago.
There are several limitations to this study. First, there is a wide range of community-based psychosocial interventions. The generalizability of these findings across different models is unknown. Second, we did not test for specificity effects between distinct neurocognitive factors and discrete domains of functional outcome. Future research should address the specificity of effects between specific domains of neurocognition (eg, immediate memory) and distinct functional outcomes (eg, work or social functioning). Third, our measure of social cognition only reflects one aspect of the larger construct. Other aspects of social cognition such as theory of mind and attributional style were not reflected in our measure. Fourth, while we did not find site effects largely because our extensive pilot data gathering allowed us to select homogenous program sites, it is possible that some site effects were undetected. Fifth, there are other moderators that could be investigated in terms of their influence on the relationship between neurocognition, social cognition, and functional outcomes. Certain type of services, such as rehabilitation or case management, might have differential effects. Similarly, the character of the alliance between consumer and practitioner is also a potentially important moderator. Better understanding of these moderators could be integrated into service design and intervention development in order to facilitate rehabilitative change. Finally, Spaulding et al64
found a nonspecific impact of intensive rehabilitation on neurocognitive performance. Prospective measures of neurocognition and social cognition would allow for a test of these effects, and they would also allow for an examination of the degree to which changes in neurocognition and social cognition are linked to changes in functional outcome which is a critical area for future investigation.