13/03/2025
This study is a systematic review and meta-analysis on processing speed (PS) and sustained attention (SA) deficits in individuals with bipolar disorder (BD) and major depressive disorder (MDD).
Key Findings
1. BD and MDD patients exhibit significant PS and SA deficits:
• Effect sizes for BD: d = 0.19–0.96
• Effect sizes for MDD: d = 0.29–0.86
• Most neuropsychological tests showed significant impairments.
2. Cognitive impairments persist in both symptomatic and euthymic states:
• Many BD and MDD patients still show PS and SA deficits even during euthymia.
• Some measures were not impaired in euthymia, suggesting partial recovery but persistent deficits in core cognitive functions.
3. Heterogeneity exists among different neuropsychological tests:
• Variability in assessment methods contributed to heterogeneity in results, which remained even after separating by mood state.
• Different PS tests (e.g., Trail-Making Test vs. Digit Symbol Substitution Test) and SA tests (e.g., Continuous Performance Test) showed varying results across patient groups.
4. Limited data for some analyses:
• Some outcome measures lacked sufficient data, particularly in symptomatic BD and MDD groups, limiting meta-analysis in those areas.
Key Contributions
• This is the first systematic study to quantify PS and SA deficits in BD and MDD using meta-analysis.
• Findings confirm that cognitive deficits persist even in euthymic states, suggesting PS and SA impairments as core features of BD and MDD.
• Highlights the need to address heterogeneity in neuropsychological testing methods for more reliable assessments.
• Suggests future research should control for clinical confounds and further investigate the effects of mood states on cognitive dysfunction.
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Little, B., Anwyll, M., Norsworthy, L., Corbett, L., Schultz‐Froggatt, M., & Gallagher, P. (2024). Processing speed and sustained attention in bipolar disorder and major depressive disorder: a systematic review and meta‐analysis. Bipolar Disorders, 26(2), 109-128.
