Social Cognition as a Mediator Variable Between Neurocognition and Functional
Outcome in Schizophrenia: Empirical Review and New Results by Structural
Stefanie J. Schmidt*, Daniel R. Mueller, and Volker Roder
University Hospital of Psychiatry, University of Bern, Bolligenstrasse 111, 3000 Bern 60, Switzerland
*To whom correspondence should be addressed; e-mail: firstname.lastname@example.org
Cognitive impairments are currently regarded as important
determinants of functional domains and are promising
treatment goals in schizophrenia. Nevertheless, the exact
nature of the interdependent relationship between neuro-
cognition and social cognition as well as the relative con-
tribution of each of these factors to adequate functioning
remains unclear. The purpose of this article is to systemat-
ically review the findings and methodology of studies that
have investigated social cognition as a mediator variable
between neurocognitive performance and functional out-
come in schizophrenia. Moreover, we carried out a study
to evaluate thismediation hypothesisby themeans of struc-
tural equation modeling in a large sample of 148 schizo-
phrenia patients. The review comprised 15 studies. All
but one study provided evidence for the mediating role of
social cognition both in cross-sectional and in longitudinal
designs. Other variables like motivation and social compe-
tence additionally mediated the relationship between social
cognition and functional outcome. The mean effect size of
the indirect effect was 0.20. However, social cognitive
domains were differentially effective mediators. On aver-
age, 25% of the variance in functional outcome could be
explained in the mediation model. The results of our
own statistical analysis are in line with these conclusions:
Social cognition mediated a significant indirect relation-
ship between neurocognition and functional outcome.
These results suggest that research should focus on differ-
ential mediation pathways. Future studies should also
consider the interaction with other prognostic factors, ad-
ditional mediators, and moderators in order to increase
the predictive power and to target those factors relevant
for optimizing therapy effects.
Key words: schizophrenia/social cognition/functional
Despite advances in antipsychotic medications as well as
psychological treatments, schizophrenia remains one of
most disabling disorders worldwide.1Functional impair-
ments in living, work, and leisure are essential diagnostic
They are associated with high direct and indirect costs6
and are often present in periods of symptom remission.7,8
is nowadays part of standardized recovery criteria9–11
and is a main focus of psychiatric rehabilitation efforts
by targeting factors contributing to functional recovery.
A large body of cross-sectional as well as longitudinal
studies provides empirical evidence for the link between
neurocognition and functional outcome in schizophre-
nia.12,13Neurocognition can be defined as processes of
linking and appraising information. It includes abilities
like speed of processing, attention, verbal and visual learn-
problem solving.14,15Despite the significant associations
between neurocognition and functional deficits, the corre-
lations are generally moderate with composite measures of
neurocognition accounting only for 20%–60% of the
variance in functional outcome.13This has prompted the
search for other factors such as mediators that may
enhance the understanding of the relationships between
neurocognition and functional impairments.
One of the most promising mediators is the area of
social cognition as it shows consistent relationships
with neurocognition well as with different functional
domains.16,17The term social cognition is defined in var-
ious ways, but generally refers to the mental operations
underlying social interactions such as the perception, in-
terpretation, and generation of responses to the inten-
tions, dispositions, and behaviors of others.18–20Social
cognition encompasses various abilities. The ones most
Schizophrenia Bulletin vol. 37 suppl. 2 pp. S41–S54, 2011
? The Author 2011. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved.
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frequently studied in schizophrenia are emotion percep-
tion (perceiving and using emotions), social perception
(apprehension of key features of social situations and
interactions), social schema/social knowledge (awareness
characterize social situations), theory of mind (ToM; the
ability to infer intentions, dispositions, and beliefs of
others), and social attributions (the ability to infer the
causes of particular positive or negative events).19Today,
distinctfrom, basicneurocognitionandmaycontribute in
a nonredundant way to functional outcome.21–23This
is consistent with functional neuroimaging research sug-
gesting that the processing of social and nonsocial infor-
mation relies on semi-independent specialized neural
networks.24–27Several studies showed that social cogni-
tion could explain an additional amount of variance after
having controlled for neurocognitive functions.28–31It
seems to be even a better predictor than neurocognition
and clinical symptoms.32Psychiatric symptoms have re-
ceived less attention as predictors of functional outcome.
be consistently associated with functional outcome. The
correlations between positive symptoms and functional
outcome were generally weaker.33
Although there is a growing literature interested in so-
nition to functional consequences, a systematic review
of current findings has been lacking. In spite of recent
advances in testing mediation effects, little attention
has been given to quantify the indirect effect across stud-
ies. In this paper, we aimed to systematically review the
findings and methodology of studies that have investi-
gated social cognition as a mediator variable between
neurocognitive performance and functional status in
schizophrenia. We estimated the strength of the indirect
effect by calculating effect sizes. Many of the reviewed
studies comprised small samples and investigated only
one social cognitive domain. We carried out a study to
evaluate this mediation hypothesis by the means of struc-
tural equation modeling (SEM). We included a large
sample of schizophrenia patients, a wide array of neuro-
cognitive measures and the social cognitive domains of
emotion perception and social knowledge as potential in-
Neurocognition and Functional Outcome in Schizophrenia
Methods of the Review
We identified 15 English language articles published
between January 2004 and December 2010 through
searches in the databases MEDLINE and PsycINFO.
cial cog*, emotion/social perception, theory of mind,
attribution, social knowledge, functional outcome, social
skills, social competence, quality of life combined with
schizophrenia or psychosis. Studies were included 1. if
diator variable between neurocognition and functional
outcome, 2. if the sample consisted of patients with a di-
agnosis of schizophrenia or schizoaffective disorder
according to Diagnostic and Statistical Manual of Mental
Disorders, Fourth Edition (DSM-IV) or International
Classification of Diseases, Tenth Version (ICD-10), and
3. if mediation effects were evaluated by regression anal-
ysis, path analysis, or SEM. These statistical techniques
We classified the neuro- and social cognitive measures
used in the selected studies according to the MATRICS
classification scheme and definitions14,19and current neu-
ropsychological literature.17,35Functional outcome meas-
social skills, social problem solving, social behavior in the
milieu, and community functioning (independent living
skills, work functioning, social functioning) (see table 1).
Results of the Review
Table 1 gives an overview of the 15
included studies,36–50their corresponding sample, and
methodological characteristics as well as the key findings.
with a diagnosis of schizophrenia or schizoaffective disor-
der according to DSM-IV or ICD-10. The mean age was
39.09 years (SD = 6.59) and the majority was male
(mean: 69%, SD = 9.79). Only one sample36,37,49explicitly
comprised first-episode psychosis patients as well as par-
ticipants with a diagnosis of other nonaffective psychotic
There was considerable variability in the reported sta-
tistical parameters (eg, R2, R2change, partial r, standard-
ized regression coefficients b) and the applied statistical
methods, with 6 studies using regression analysis,36–41
5 studies path analysis,37–46and 5 studies SEM.47–50
Moreover, studies differed in the applied statistical pro-
cedure to test mediation effects: Nine studies estimated
the parameters of the mediation model while controlling
for the direct effect of neurocognition on functional out-
come.47,48Others excluded the estimation of the direct
effect a priori or in the final mediation model.44,45Al-
though being the most important criterion for a media-
tion effect,51only 8 studies39,48reported size and
significance level of the indirect effect.
with wide variation among the studies in the selection
of measures and in the applied statistical methods, some
general conclusions are warranted. In summary, all but
one study38found evidence for the mediating role of social
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