Article

Cognitive Impairment in Affective Psychoses: A Meta-analysis

Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne and Melbourne Health, Alan Gilbert Building NNF Level 3, Carlton 3053, Australia.
Schizophrenia Bulletin (Impact Factor: 8.61). 09/2009; 36(1):112-25. DOI: 10.1093/schbul/sbp093
Source: PubMed

ABSTRACT It has recently been suggested that cognitive impairment should be included in the diagnostic criteria of schizophrenia. One of the main arguments in support of this suggestion has been the hope that cognitive impairment can help distinguish schizophrenia from bipolar disorder (BD). However, recent evidence shows that cognitive deficits occur in BD and persist beyond euthymia. Further, mood disorders with psychotic features might be expected to manifest greater cognitive impairment, which further complicates the potential to differentiate these disorders. The goal of the current meta-analysis was to examine the magnitude and characteristics of cognitive impairments in affective psychoses (AP). A systematic search of the existing literature sourced 27 studies that met the inclusion criteria. These studies compared cognitive performances of 763 patients with AP (550 BD and 213 major depressive disorder) and 1823 healthy controls. Meta-regression and subgroup analyses were used to examine the effects of moderator variables. Meta-analyses of these studies showed that patients with AP were impaired in all 15 cognitive tasks with large effect sizes for most measures. There were no significant differences between the magnitude of impairments between the BD and major depressive disorder groups. The largest effect size was found for symbol coding, stroop task, verbal learning, and category fluency, reflecting impairments in elementary and complex aspects of attentional processing, as well as learning and memory. In general, the pattern of cognitive impairments in AP was similar to reported findings in euthymic patients with BD, but relatively more pronounced.

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    • "It is known that cognitive impairment is not restricted to symptomatic phases, but that it also accompanies euthymia in a substantial number of bipolar patients, even though the published evidence is heterogeneous with regard to the specific functions affected, degree of impairment, and the degree of variability explained by the disorder itself compared to that attributed to moderating and mediating variables (Jamrozinski 2010). There seems to be a correlation between the duration of illness (DOI) as well as the number of illness episodes (especially depressive ones) and the degree of impairment (Bearden et al. 2001, Bora et al. 2010). Data on the latter, however, are discordant and even the causal direction is not yet clear (Martino et al. 2014). "
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    12/2014; 2(1):1. DOI:10.1186/s40345-014-0016-7
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    • "Cognitive deficits represent stable traits in both schizophrenia and bipolar disorder [1]. Studies that have directly compared the two groups show qualitatively similar deficits, but quantitatively, milder deficits in bipolar disorder [2– 4]. "
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    ABSTRACT: Cognitive deficits in various domains have been shown in patients with bipolar disorder and schizophrenia. The purpose of the present study was to examine if residual psychopathology explained the difference in cognitive function between clinically stable patients with schizophrenia and bipolar disorder. We compared the performance on tests of attention, visual and verbal memory, and executive function of 25 patients with schizophrenia in remission and 25 euthymic bipolar disorder patients with that of 25 healthy controls. Mediation analysis was used to see if residual psychopathology could explain the difference in cognitive function between the patient groups. Both patient groups performed significantly worse than healthy controls on most cognitive tests. Patients with bipolar disorder displayed cognitive deficits that were milder but qualitatively similar to those of patients with schizophrenia. Residual negative symptoms mediated the difference in performance on cognitive tests between the two groups. Neither residual general psychotic symptoms nor greater antipsychotic doses explained this relationship. The shared variance explained by the residual negative and cognitive deficits that the difference between patient groups may be explained by greater frontal cortical neurophysiological deficits in patients with schizophrenia, compared to bipolar disorder. Further longitudinal work may provide insight into pathophysiological mechanisms that underlie these deficits.
    06/2014; 2014:785310. DOI:10.1155/2014/785310
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    • "An association between bipolar disorder (BD) and cognitive dysfunction has been established in over 75 studies (Bearden et al., 2001; Robinson et al., 2006; Torres et al., 2007; Arts et al., 2008; Bora et al., 2010). These cognitive impairments are a major contributor to disability in BD, particularly with advancing age (Bowie et al., 2010; Bearden et al., 2011), and are distinct from normal age-related cognitive decline (Gildengers et al., 2005; Andreasen, 2010; Gildengers et al., 2012b). "
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