Executive functions and memory in bipolar disorders I and II: new insights from meta-analytic results.Objective: To perform a systematic review and meta-analysis of executive functions (EF) and episodic memory in bipolar disorder (BD). Methods: A literature search was conducted on three electronic databases. Results were combined using random-effects meta-analysis. Results: A total of 126 studies (6424 patients with BDI, 702 with BDII, and 8276 controls) were included. BDI was associated with moderate to large impairments across all cognitive functions and BDII with small-tomedium impairments. Small significant differences were identified between BDI and BDII on all cognitive functions except inhibition. The Trail Making Test (TMT) (g = 0.74, 95% CI: 0.67-0.80), Hayling Test (g = 0.58, 95% CI: 0.34-0.81), Digit Span Total (g = 0.79, 95% CI: 0.57-1.01), and Category Fluency (g = 0.59, 95% CI: 0.45-0.72) tasks were most sensitive to cognitive impairment in BDI. The TMT (g = 0.65, 95% CI: 0.50-0.80) and Category Fluency (g = 0.56, 95% CI: 0.37-0.75) were also sensitive to cognitive alterations in patients with BDII. Conclusion: BD type I was associated with more severe and widespread impairments than BDII, which showed smaller impairments on all functions except inhibition, where impairments were larger. Education and (hypo)manic symptoms should be further investigated in future studies due to their possible influence on the neuropsychological profile of BD. The instruments identified in this review should be considered for inclusion in cognitive assessment batteries in BD.
Summations• Patients with BD type I performed worse than control subjects with moderate to large effect sizes, while patients with BD type II showed impairments with small-to-medium effect sizes. Small significant differences were identified between BD types I and II on all cognitive functions except inhibition.• Education, (hypo)mania symptom scores, and lithium use moderated cognitive impairments in BD.• The TMT B, Hayling Test B, Digit Span Total, and Category Fluency were most sensitive to cognitive impairments and to differences between cognitive performance in individuals with BD types I and II.
Limitations• Small number of studies involving BD type II. • Large heterogeneity in effect sizes. • Inconsistent reporting of potential moderator variables (mood symptoms, medication use, comorbidities).
Objectives: Cognitive dysfunction is a key feature of major depressive (MDD) and bipolar (BD) disorders. However, rather than a single cognitive profile corresponding to each diagnostic categories, recent studies have identified significant intra-and cross-diagnostic variability in patterns of cognitive impairment. The goal of this study was to contribute to the literature on cognitive heterogeneity in mood disorders by identifying cognitive subprofiles in a population of patients with MDD, BD type I, BD type II, and healthy adults. Methods: Participants completed a neuropsychological battery; scores were converted into Z-scores using normative data and submitted to hierarchical cluster analysis. Results: Three distinct neuropsychological clusters were identified: (1) a large cluster containing mostly control participants, as well as some patients with BD and MDD, who performed at above-average levels on all neuropsychological domains; (2) a cluster containing some patients from all diagnostic groups, as well as healthy controls, who performed worse than cluster 1 on most tasks, and showed impairments in motor inhibition and verbal fluency; (3) a cluster containing mostly patients with mood disorders with severe impairments in verbal inhibition and cognitive flexibility. Conclusions: These findings revealed multiple cognitive profiles within diagnostic categories, as well as significant cross-diagnostic overlap, highlighting the importance of developing more specific treatment approaches which consider patients' demographic and cognitive profiles in addition to their diagnosis. (JINS, 2017, 23, 584-593)
The increased intensity with which emotions were perceived by patients with BD and MDD has important repercussions for patient functioning and clinical practice. A tendency to overestimate the intensity of certain facial expressions in mood disorders may lead patients to interpret social cues erroneously and engage in dysfunctional behaviors and cognitive patterns. Future studies should focus on this variable in addition to the accuracy of emotion identification.
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