High allostatic status impairs cognitive function in patients with first-episode drug-naive bipolar disorder

Patients with bipolar disorder (BD) are often experience cognitive impairment. Allostatic load (AL) represents the cumulative physiological burden on the body resulting from prolonged or chronic stress, which plays a key role in the pathophysiology of BD. This study aimed to investigate the relationship between AL and cognitive function in first-diagnosed, drug-naïve BD patients.

Patients with BD (n = 113) recruited from March 2019 to August 2022, along with healthy controls (HCs, n = 115) recruited during the same period. Body mass index (BMI), waist-to-hip ratio (WHR), high-density lipoprotein cholesterol (HDL), total cholesterol (TC), blood glucose, C-reactive protein (CRP), cortisol and serum dehydroepiandrosterone (DHEA) levels were measured to calculate AL. Clinical symptoms were assessed using the Hamilton Depression Scale (HAMD), Hamilton Anxiety Scale (HAMA), and Young's Mania Rating Scale (YMRS). Cognitive function was evaluated using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and the Stroop Word Test. Differences in AL, eight biological indicators, and cognitive performance were compared between the BD and HC groups. Covariate analyses were conducted to examine correlations between AL and cognitive function, with further gender subgroups analysis to explore specific factors affecting cognition in BD.

AL levels were significantly higher in the BD group (U = 5096, P = 0.004) compared to HC. Cognitive performance, as measured by RBANS (t = 6.359, P < 0.0001) and Stroop test (t = 4.516, P < 0.0001) scores, was significantly lower in BD patients. Cortisol levels were positively correlated with delayed memory performance (r = 0.29, P = 0.027), whereas CRP levels were negatively correlated with delayed memory performance (r = -0.31, P = 0.020). In the male subgroup, a negative correlation was observed between AL and RBANS scores (r = -0.48, P = 0.009).

Elevated AL may contribute to the pathophysiology of BD and the observed reduction of cognitive performance.