The amygdala in bipolar disorder: A cross-sectional study examining the relevance of structural alterations of amygdala subfields for cognitive functioning in patients with bipolar disorder.

BACKGROUND

Bipolar disorder (BD) is associated with cognitive impairment. Structural alterations of the amygdala may contribute to these deficits, although evidence has been inconsistent. This study examined the relationship between amygdala subfield volumes and cognitive performance to understand the neurobiological basis of cognitive impairment in BD.

METHODS

Amygdala volumes were measured in 42 patients with BD [16 female, 26 male; M(age) = 44.33 ± 12.97 years] and 67 healthy controls [44 female, 23 male; M(age) = 40.53 ± 16.21 years] using 3-Tesla MRI. Cognitive performance was assessed across verbal learning/memory, executive function, and attention. Statistical analysis included partial correlations, analysis of variance (ANOVA) and hierarchical regressions.

RESULTS

Memory performance correlated significantly with left amygdala subfield volumes. No associations were observed for other cognitive functions. ANOVA revealed significantly smaller volumes in some left and right amygdala subfields in BD patients with more severe cognitive impairment, whereas others were not significant. Left amygdala subfield volumes significantly predicted memory performance in BD.

CONCLUSION

Reduced volumes of left amygdala subfields are associated with impairment in verbal learning/memory. These findings highlight a potential role of amygdala structural alterations in BD-related cognitive deficits and suggest the amygdala as a potential biomarker for memory dysfunction in BD.