The relationship between peripheral insulin resistance and social cognitive deficits among euthymic patients with...

Despite extensive literature documenting emotion-related social-cognitive deficits in euthymic patients with bipolar disorder (BD), the factors contributing to these deficits have not been definitively established. To address this gap, the present study aimed to examine the association between peripheral insulin resistance (IR) and emotion-related social-cognitive abilities in BD patients and controls.

Sixty-five BD patients and 38 non-psychiatric controls were recruited, and their social cognitive ability and IR were measured using the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT) and the homeostasis model assessment of insulin resistance (HOMA-IR), respectively.

The study found that the BD patients scored significantly lower than the non-psychiatric controls in the task of emotional management. The BD patients had a higher mean HOMA-IR value as compared with the controls but this result was not statistically significant (p = 0.051). The interaction between BD diagnosis and HOMA-IR value was significant on the MSCEIT Facilitating emotions branch and Facilitation subscale (p = 0.024, p = 0.010), and post-hoc analyses revealed that the BD patients in the higher HOMA-IR group had significantly lower scores than BD patients in the lower HOMA-IR group and the non-psychiatric controls in the higher HOMA-IR group on both the MSCEIT Facilitating emotion branch and Facilitation subscale.

Due to the cross-sectional nature of the study, causality could not be inferred. The study did not examine potential mediators or moderators between IR and social cognition.

The results suggested that BD patients with IR experience additional impairment in specific domains of social cognition.