Cognitive impairment in schizoaffective disorder:
greater or lesser impairment than schizophrenia or
bipolar disorder?
Carla Torrent
Bipolar Disorder Program
Hospital Clínic Barcelona
IRPB, Lisbon, 26th april 2015
Neurocognition and schizoaffective
disorder (SAD)
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The classical, kraepelinian classification of mental disorders
makes a distinction between dementia praecox and manicdepressive disorder.
In clinical practice, some patients present a mixture of
schizophrenic and affective signs and symptoms.
In more recent nosologic systems, a new diagnostic
category: schizoaffective disorder
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A form of schizophrenia (SZ)
A form of bipolar disorder (BD)
An independent disorder
A disorder intermediate between SZ and BD
One of the aims of research on neurocognition is to
validate these diagnostic categories.
Psychiatric disorders are associated with
complex patterns of cognitive impairment
• Attention
• Executive function
• Verbal learning and memory
• Speed of processing
• Social cognition
• Language
Genetic
Epigenetic
Developmental
Environmental
Adapted from Millan et al., Nature, 2012
Cognitive impairment by cognitive domains
Millanet al, 2012
Epidemiological, genetic, neuroimaging and neurocognitive studies show similarities
between SZ and BD.
Cognitive impairment in SQZ and BD
Schizophrenia
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Prevalence 85-100%
Impairment across domains deficits 1-2
SD (verbal memory and processing
speed)
Present at illness onset and remain
relatively stable over the course of the
illness
Do not change substantially with
antipsychotic medications
Account for much of the functional
disability associated with the illness.
Broad cognitive impairment is not
attributable to reduced general intellect
Bipolar disorder
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Prevalence 40-60%
Cognitive impairment during
remission
Impairments present early in the
course of illness
Do not change substantially with
available treatments
Bipolar I > Bipolar II
Higher number of manic episodes
Related to functional dysfunction
Increased in patients with history
of psychotic symptoms
Cognitive development in subjects with
schizophrenia, bipolar disorder and healthy
controls
Lewandowski et al, Psych Med, 2010
A longitudinal study of cognitive functioning in
schizophrenia
N=132
Mean age: 43.7 years
The results showed an absence of
cognitive decline for most measures
and modest gains in some measures
over a period of up to 10 years
Dickerson et al, Schiz Res, 2014
Premorbid intellectual, behavioral and language
functioning in schizophrenic, schizoaffective and
nonpsychotic bipolar patients
SAD showed premorbid deficits on 3 of 4 intellectual measures, as well as on four of 5 behavioral measures.
Future SAD scored worse than future BD on all four premorbid intellectual measures and on the reading and
comprehension tests.
Reichenberg et al, Am J Psychiatry, 2002
Neuropsychological function and dysfunction
in schizophrenia and psychotic affective
disorders
N=235
Prevalence of NP normality ranged between:
All groups
demonstrated
impairments in
16% and
45% in schizophrenia,
cognitive
domains. However,
SZ
20%all
and
33% in schizoaffective
disorder,
patients
were
impaired
than the
42% and
64%more
in bipolar
disorder,
other
and 42% and
77%groups.
in depression
Reichenberg et al, Schizophr Bull, 2009
Studies comparing SAD with SZ
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Cognitive deficits in SAD do not differ significantly
from those of SZ.
In the absence of comparisons with BD, no
conclusions can be drawn with regard to SAD as a
form of SZ or an intermediate disorder between
BD and SZ.
In some studies SZ and SAD patients were pooled
together.
Studies comparing SAD with SZ
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In other studies, patients with psychotic disorders and
those with affective disorders presenting psychotic
symptoms were pooled together.
Beatty et al, 1993; Bornstein et al, 1990; Evans et al, 1999; Glahn et
al, 2006; Goldstein et al, 2005; Gooding et al, 2002; Jeste et al, 1996;
Miller et al, 1996; Stip et al, 2005, Simonsen et al, 2009
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Other studies show that SAD perform better than SZ
on neuropsychological measures
Heinrichs et al, 2008; Stip et al, 2005; Szoke et al, 2008
Neuropsychological studies comparing SAD with
BD
Study
Characteristics
Findings
Evans et al, 1999
N=154 SZ
N=29 SAD
N=27 non psychotic mood
disorder
SAD and SZ more impaired that non psychotic
mood disorder patients,
No significant differences between SZ and SAD
Psychotic spectrum
Glahn et al, 2006
N=15 SZ
N=15 SAD
N=15 BD non psychotic
Lack of significant differences between the groups
Psychotic spectrum
Szoke et al, 2008
N=26 SAD
N=52 BP with psychosis
N=51 BD
N=65 controls
Executive functions: non significant differences in a
executive measure (TMT)
SZ<SAD<BP with psychosis<BD<C on the
WCST perseverative errors
Continuum in psychosis
Reichenberg et al, 2009
N=94 SZ
N= 15 SAD
N=78 psychotic BD
N=48 psychotic MD
Greater impairment in SZ and SAD in
comparison to both psychotic mood disorders,
no differences between SZ and SAD
Cognitive deficits are common to the psychotic spectrum regardless of specific
diagnostic
N= 28 SAD
N= 32 BP
Schizoaffective patients showed more impairment than
bipolar patients on tests of attention, psychomotor speed
and memory, but there were not significant differences on
measures of cognitive flexibility
A worse cognitive outcome of SAD compared to BP patients in remission
Studentkowski et al., 2010
N=34 SAD N=41 BD without psychosis N=35 healthy controls
Cognitive functioning in SAD and nonpsychotic BD
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SAD showed greater impairment than controls and BD
in verbal memory, executive functions and attentional
measures.
BD performed similar to the controls except for verbal
fluency.
SAD carries more neurocognitive impairment than
nonpsychotic BD and more occupational difficulties.
Lithium and antipsychotics did not seem to influence
results.
History of psychosis was the best predictor of verbal
memory impairment.
N=545
N=102 SZ
N=27 SAD
N=75 psychotic BD
N=61 non psychotic BD
N=280 heatlhy controls
Simonsen et al, 2011
Results
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SZ, SAD, psychotic BD < nonpsychotic BD, HC
Nonpsychotic BD < HC (only on processing speed)
Psychotic BD < nonpsychotic BD (verbal fluency and
interference control).
Neurocognitive dysfunction in bipolar and SZ spectrum
disorders seems to be determined more by history of
psychosis than by DSM-IV diagnostic category or
subtype.
Neurocognition as an endophenotypic marker for these
disorders.
Simonsen et al. Schizophr Res, 2011
Executive dysfunction and memory impairment
in schizoaffective disorder
WAIS-III / TAP
 SAD schizomanic = 26
 BD manic =51
(psychotic/ non-psychotic)
Acute Schizophrenic =45
 Controls=65
Psychopathological assessment
(Young, PANSS)
Wechsler Memory Scale-III (WMS)
Assessment Dysexecutive
Syndrome (BADS)
The aim of the study was to examine whether there is a pattern of
decreasing cognitive impairment from SZ to SAD to BD.
Amann et al, 2011
Executive dysfunction and memory impairment
in schizoaffective disorder
Memory (WMS-III)
No differences between patient groups on
composite score, verbal memory and
working memory.
Visual memory differences between SZ and HC.
Controls
BD
manic
SAD
schizomanic
Schizophrenic
Executive functions (BADS)
All 3 patient groups were more
impaired in the BADS than controls.
Differences in Action program test:
SZ < Bip= SAD
Controls
BD manic
SAD
schizomanic
Schizophrenic
Amann et al, 2011
Executive dysfunction and memory impairment
in schizoaffective disorder
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Out of 10 tests, there was only one significant difference:
SAD and BD patients peformed better than the SZ
patients on the Action Program Test of the BADS, which
tests problem-solving skills.
SZ, SAD and manic patients show a similar degree of
executive and memory deficits in the acute phase of the
illness.
No significant differences were found between psychotic
(n=22) and nonpsychotic (n=29) bipolar patients.
These findings do not support a categorical differentiation
across different psychotic categories with regard to
neuropsychological deficits.
Cognitive functioning in schizoaffective
disorders
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Cognitive functioning in affective
psychosis and schizoaffective disorder is
much less studied compared with
schizophrenia.
31 studies that compared the
performances of people with SZ
(n=1979) with that of those with
affective psychosis or schizoaffective
disorder (n=1314) were included.
In 6 of 12 cognitive domains, people
with SZ performed worse than people
with schizoaffective disorder or
affective psychosis.
Bora et al, BJP 2009
Cognitive functioning in schizoaffective
disorders
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Between-group differences were driven by a higher
percentage of males, more severe negative
symptoms and younger age at onset of illness in SZ.
Neuropsychological data do not provide evidence
for categorical differences between SZ and other
groups.
However, a subgroup of individuals with SZ with
more severe negative symptoms may be cognitively
more impaired than those with affective
psychosis/schizoaffective disorder.
Bora et al, BJP 2009
Cognitive functioning in schizoaffective
disorders
Two different alternatives of the Kraepelinian dichotomy:
 The most severe SZ and psychotic BD may lie on the
opposite ends of a continuum, with only a quantitative
change in the degree of cognitive dysfuntion along the
continuum from SZ and psychotic mood disorders.
 Only people with SZ with more severe negative symptoms
are more impaired in certain domains (‘deficit’ SZ):
categorical distinction between a subgroup with poor
outcome SZ and other psychotic disorders including
people with SZ with a good prognosis.
Bora et al, BJP 2009
Cross-diagnostic cognitive study
SZ: 293
SAD: 165
Psychotic BD: 227
Healthy Controls: 295
Robust neuropsychological
impairment are present in SZ
and psychotic BD. The
severity of cognitive across
psychotic disorders was
consistent with a continuum .
with SZ having greater
impairment than SAD and
SAD greater than BD
Hill et al. AJP, 2013
Conclusions
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Available evidence strongly supports that a generalized deficit is
present across psychotic disorders that differs in severity more
so than form.
Cognitive performance in groups of psychotic patients may be
influenced by the degree to which they are symptomatic at the
time of testing (8-12 weeks of remission before testing).
SAD vs. BD: One possible reason for the divergent findings may
be the presence or absence of psychotic symptoms in BD.
Findings suggest that SZ, SAD and BDP are on a neurobiological
continuum.
Conclusions
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Cognitive testing as well as functional assessment may be useful
in clinical practice to determine the extent of difficulties,
beyond diagnosis or subtypes.
A more complex, mixed, dimensional-categorical model could
better explain the available data.
Early detection and intervention of cognitive deficits are
essential to reduce disability in SZ, SAD and BD (optimizing
individualized pharmacological treatment + CR). Cognitive
remediation has at least equivalent benefits in affective and
schizoaffective disorder as demonstrated in schizophrenia.
Antoni Benabarre
Mar Bonnín
Francesc Colom
Mercè Comes
Marina Garriga
Jose M Goikolea
Iria Grande
Diego Hidalgo
Esther Jiménez
Anabel Martinez-Arán
Andrea Murru
Isabella Pacchiarotti
Rosa Palaus
Dina Popovic
María Reinares
Jose Sánchez-Moreno
Brisa Solé
Carla Torrent
Imma Torres
Marc Valentí
Èlia Valls
Cristina Varo
Eduard Vieta
Ackowledgements