Supplemental Materials
Relationship of CNTRACS and MATRICS Tasks to Symptoms in Schizophrenia
Another important question is the degree to which tasks from the MATRICS and
CNTRACS batteries relate to clinical symptom severity. One concern in using cognitive
tasks in treatment trials has been the issue of “psuedospecificity” (Breier, 2005), or the
degree to which changes in psychotic symptoms may lead to the appearance of
changes in cognitive function. Fortunately, there is a good deal of evidence to suggest
that the severity of higher cognitive deficits in schizophrenia is not related to the severity
of psychotic symptoms such as hallucinations and delusions (Ventura et al., 2010),
although, consistent with Bayesian models of psychosis (Clark, 2013; Corlett et al.,
2010), visual processing tasks that measure the influence of stored knowledge on
perception have shown strong relationships with positive symptoms (e.g., patients who
fail to see common illusions, and therefore see test objects veridically, tend to be those
with higher levels of positive symptoms, with both phenomena through to reflect the
same core abnormality; Keane et al., 2013). However, it has recently been shown that
the working memory and processing speed tasks in the MATRICS battery, as well as the
composite score, significantly correlated with negative symptoms. Further, disorganized
symptoms correlated with the overall composite score, processing speed, verbal
learning, visual learning and social cognition (August et al. 2012). The CNTRACS task of
goal maintenance (AX- CPT/DPX) has also shown a significant relationship with
disorganized symptoms (Gold et al. 2012), as has an earlier version of the JOVI when
used in inpatient samples (Silverstein et al., 2000; Uhlhaas et al., 2005, Uhlhaas et al.,
2006). Given that these previous studies on the relationships to symptom severity in the
MATRICS versus CNTRACS batteries were conducted in different samples, one of the
goals of the current study was to compare performance on the CNTRACS tasks and a
subset of the MATRICS tasks to clinical symptoms in the same participants.
Are clinical symptoms related to cognition or function?
Correlations between the cognitive tasks and symptom measures were nonsignificant after correcting for multiple comparisons (Supplemental Table). This was true
even when looking at the common factor score. At a nominal p-value of .05, the AX-CPT,
the DPX, and the HVLT-R were correlated with mania, and the HVLT-R was also
correlated with disorganized symptoms. Interestingly, however, the measures of function
were significantly correlated with symptoms. The MSIF and UPSA-B correlated
significantly with all measures of clinical symptoms (positive, disorganized, negative,
manic, and depressed). The SLOF Patient report was significantly correlated with
positive, disorganized, and depressed symptoms, but the SLOF Informant report only
showed a significant relationship with manic symptoms. To better understand the
contribution of clinical and cognitive measures to functional outcome, we also performed
partial correlations. After controlling for all clinical symptoms, the RISE, AX-CPT, DPX,
and BACSsc all remained significantly correlated with the UPSA-B, and the HVLT-R
remained significantly correlated with the MSIF and SLOF Patient report. After
controlling for performance on all cognitive paradigms, disorganized, negative, and
depressed symptoms remained significantly correlated with the UPSA-B. In addition,
positive, disorganized, negative, and depressed symptoms remained significantly
correlated with the MSIF, and positive and disorganized symptoms remained
significantly correlated with the SLOF Patient report. Thus, symptoms and cognitive
function seem to make independent contributions to performance of life skills.
Associations with Clinical Symptoms
None of the tasks significantly correlated with clinical symptom severity after
correcting for multiple comparisons. For positive symptoms, these results are consistent
with a large body of literature (Addington et al. 1991; Nieuwenstein et al. 2001).
However, the lack of association with negative or disorganization symptoms is
somewhat surprising. As noted in the main text, this was a fairly highly functioning
sample with relatively low levels of symptoms, and the low scores and limited variance
might have reduced our sensitivity to detect such correlations. That said, the majority of
functioning measures were associated with symptom levels across domains, indicating
that reduced variance was not the only explanation for non-significant relationships
between cognition and symptoms. Further, most of the function and symptom measures
remained significantly correlated after controlling for variance associated with the
cognitive tasks, and most of the cognitive tasks remained significantly correlated with the
UPSA-B after controlling for clinical symptoms. Previous work has shown this pattern in
a large group of schizophrenia patients, whose changes in neuropsychological
performance were seemingly independent from changes in clinical symptoms (Harvey et
al. 2006). Our findings are consistent with this prior work, and suggest that cognitive
function and clinical symptoms make independent contributions to levels of function.
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Supplemental Table: Clinical Characteristic Correlation Coefficients with Cognitive Performance and Functional Outcome in Patients
Positive Symptoms
Disorganized
Symptoms
Negative Symptoms
Manic
Symptoms
Depressed
Symptoms
RISE IRIE
-.05
-.05
.01
-.05
.09
RISE IRAE
-.06
-.11
-.01
-.05
.06
RISE AR
.05
-.03
.08
.03
.14
AX-CPT D’-context
.01
-.09
-.04
-.21*
.02
DPX D’-context
-.04
-.13
-.08
-.26*
-.06
JOVI Threshold
-.10
.07
-.01
.08
.01
BACSsc
-.00
-.15
-.09
-.00
.01
HVLT-R
-.18
-.22*
-.09
-.20*
-.15
UPSA-B
-.22*
-.39***
-.40***
-.38***
-.19*
MSIF Global
.47***
.43***
.37***
.25*
.32**
SLOF Patient
-.31**
-.36***
-.12
-.06
-.38***
SLOF Informant
-.15
-.27*
-.18
-.37**
.00
* p<.05, ** p<.01, *** p<.001