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Processing speed and sustained attention in bipolar disorder and major depressive disorder: A systematic review and meta-analysis

Lookup NU author(s): Dr Beth LittleORCiD, Laura Norsworthy, Luke Corbett, Mia Schultz-Froggatt, 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.

Publication metadata

Author(s): Little B, Anwyll M, Norsworthy L, Corbett L, Schultz-Froggatt M, Gallagher P

Publication type: Review

Publication status: Published

Journal: Bipolar Disorders

Year: 2024

Volume: 26

Issue: 2

Pages: 109-128

Print publication date: 01/03/2024

Online publication date: 16/11/2023

Acceptance date: 08/11/2023

ISSN (print): 1398-5647

ISSN (electronic): 1399-5618


DOI: 10.1111/bdi.13396