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Lookup NU author(s): Dr Beth LittleORCiD,
Dr Peter GallagherORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
Objectives: Cognitive impairment is a core feature of bipolar disorder (BD) and major depressive disorder (MDD). Deficits in processing speed (PS) and sustained attention (SA) may be particularly impaired and may underpin a broader profile of deficits, however current knowledge of the nature of these impairments is limited by heterogeneous results in the literature. Few reviews to date have attempted to disentangle sources of heterogeneity to assess the presence and magnitude of impairments in PS and SA in BD and MDD. Methods: One hundred and three studies were reviewed to examine performance in tests of PS and SA in BD (n=3,452) and MDD (n=5,461) compared to healthy controls (n=8,016). Neuropsychological methodology used in the literature was summarised. Data were meta-analysed to assess impairments in PS and SA for each neuropsychological test separately. Subgroup analysis was performed across mood states to investigate sources of heterogeneity. Results: Impairments were found across most neuropsychological tests, with small to large effect sizes for BD (range: d=0.19 to d=0.96) and MDD (range: d=0.29 to d=0.86). Impairments were present in symptomatic states and euthymia in most cases. Some outcome measures were not impaired in euthymia. Heterogeneity was observed for most neuropsychological tests and remained after separating by mood state. There was inadequate data to meta-analyse some outcome measures, particularly for symptomatic groups. Conclusion: Impairments in PS and SA in BD and MDD can be observed across most neuropsychological tests. Future research should further investigate the nature of these impairments across mood states, controlling for clinical confounds.
Author(s): Little B, Anwyll M, Norsworthy L, Corbett L, Schultz-Froggatt M, Gallagher P
Publication type: Review
Publication status: Published
Journal: Bipolar Disorders
Pages: epub ahead of print
Online publication date: 16/11/2023
Acceptance date: 08/11/2023
ISSN (print): 1398-5647
ISSN (electronic): 1399-5618