Abstract
BACKGROUND: Cognitive impairment in major depressive disorder (MDD) may be driven by neuro-inflammatory processes involving pro-inflammatory cytokines. AIMS: This study aimed to examine the relationship between serum tumour necrosis factor-alpha (TNF-α) levels and cognitive performance across different domains in individuals with MDD. METHOD: Sixty patients with MDD and 60 healthy controls were recruited. Cognitive function was assessed using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), and serum TNF-α levels were measured via flow cytometry. RESULTS: After adjusting for covariates, RBANS total and subscale scores were significantly lower in MDD patients compared with controls (P < 0.001), while log(10)-transformed TNF-α levels were significantly higher in the MDD group (P = 0.006). In MDD patients, log(10)TNF-α levels were inversely correlated with immediate memory scores after adjusting for confounding factors (r = -0.35, P = 0.009); however, this relationship was not observed in healthy controls (r = -0.02, P = 0.90). Stepwise multivariate regression analysis further confirmed the negative association of log(10)TNF-α with immediate memory scores in MDD patients (β = -14.58, t = -4.14, P < 0.001), but not in healthy controls (β = -0.02, t = -0.14, P = 0.89). CONCLUSIONS: These findings suggest that elevated serum TNF-α may contribute to the pathophysiology of MDD and is specifically associated with deficits in immediate memory.