Associations between structural brain measures and cognitive function in bipolar disorder: a systematic review and...

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Science

Background:

• Bipolar disorder (BD) is a chronic mental health condition associated with significant cognitive deficits impacting daily functioning.
• Understanding the neural basis of these cognitive impairments is essential for developing targeted interventions.

Purpose of the Study:

• To systematically review and meta-analyze the relationship between structural brain measures and cognitive performance in adults with bipolar disorder.
• To identify factors that may moderate the observed brain-cognition associations.

Main Methods:

• Systematic review and meta-analysis of 80 studies, with 50 included in meta-analyses.
• Inclusion of studies with adults diagnosed with BD, utilizing structural and diffusion-weighted MRI and cognitive assessments.
• Meta-regression analysis to explore moderating factors such as bipolar subtype and mood state.

Main Results:

• Significant associations found between grey matter and white matter indices and cognitive functioning, with moderate effect sizes.
• Substantial heterogeneity observed in these associations.
• Bipolar I subtype and euthymic mood state showed stronger associations with grey matter metrics; cognitive domain differences also played a key role.

Conclusions:

• Structural alterations in grey and white matter are meaningfully associated with cognitive difficulties in bipolar disorder.
• Brain networks may offer a global framework for understanding these brain-cognition relationships.
• Findings emphasize the need to consider both global and specific neural factors in the pathophysiology of cognitive impairment in BD.