Objective: This study aimed to compare miR-135a and miR-221 levels among patients with first-episode depression and recurrent depression, examining their association with cognitive performance.
Method: A total of 97 first-episode depression patients, 104 recurrent depression patients hospitalized from April 2019 to December 2021, and 60 healthy individuals as a control group underwent cognitive function assessment using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Serum inflammatory cytokine levels and miR-135a and miR-221 levels were measured. The correlation between miR-135a, miR-221, cognitive function, and inflammatory cytokines in depression patients was analyzed.
Results: Significant differences were observed in immediate memory, speech function, visual span, delayed memory, attention, and total RBANS scores among the three groups (P < .05). Both first-episode and recurrent depression groups scored lower than the control group across all cognitive function measures (P < .05), with the recurrent depression group exhibiting lower scores than the first-episode depression group (P < .05). Inflammatory markers (hs-CRP, TNF-α, IL-6) showed substantial variations among the groups (P < .05). miR-135a and miR-221 levels significantly differed among the three categories (P < .05). Correlation analyses revealed a negative association between miR-135a and IL-6, TNF-α, hs-CRP (P < .05), and a positive correlation with cognitive function. MiR-221 demonstrated significant connections with inflammatory markers and negative correlations with immediate memory, verbal function, visual span, delayed memory, attention, and RBANS total score ( < .05).
Conclusion: Patients with depression exhibit cognitive impairment, with recurrent depression associated with more severe impairment. The downregulation of miR-135a and upregulation of miR-221 may play a role in the cognitive impairment process by regulating inflammatory responses. The findings suggest a potential link between microRNA expression and cognitive dysfunction in depression.