Association between increased serum TNF-α levels and immediate memory impairment in patients with major depressive...

Cognitive impairment in major depressive disorder (MDD) may be driven by neuro-inflammatory processes involving pro-inflammatory cytokines.

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.

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.

After adjusting for covariates, RBANS total and subscale scores were significantly lower in MDD patients compared with controls (P < 0.001), while log₁₀-transformed TNF-α levels were significantly higher in the MDD group (P = 0.006). In MDD patients, log₁₀TNF-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 log₁₀TNF-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).

These findings suggest that elevated serum TNF-α may contribute to the pathophysiology of MDD and is specifically associated with deficits in immediate memory.