Objective To investigate the differences of the serum levels of inflammatory factors among adolescent patients with depressive disorders at different onset ages, and their correlations with clinical characteristics.

Methods The adolescent patients with depressive disorders aged 13 to 18 years who were hospitalized from January 2023 to June 2024 were selected. According to the age of onset, they were divided into the children group (＜13 years old) with 40 cases and adolescent group (≥13 years old) with 109 cases. Meanwhile, 30 healthy adolescents were selected as the control group. The clinical characteristics were evaluated by the Hamilton Depression Scale (HAMD-17) and Childhood Trauma Scale (CTQ), and the serum concentrations of tumor necrosis factor (TNF)-α and eosinophil activating chemokine (Eotaxin)-3 were detected by enzyme-linked immunosorbent assay.

Results The differences of the age among the three groups were statistically significant difference (P ＜ 0.05). The duration of depression in the childhood group was longer than that in the adolescent group (P ＜ 0.05). Among the depression subgroups, the total CTQ score and physical abuse score in the childhood group were higher than those in the adolescent group (P ＜ 0.05), while there was no statistical significance in the HAMD score (P ＞ 0.05). After controlling the age factors, the TNF-α level in the adolescent group was higher than that in the childhood group (P ＜ 0.05), and which in the depression subgroup was lower than that in normal control group (P ＜ 0.05). There was no statistically significant difference in Eotain-3 among three groups (P ＞ 0.05). The results of correlation analysis showed that in the depression group, the level of TNF-α was positively correlated with age (r = 0.256, P ＜ 0.01), and the concentration of Eotain-3 was positively correlated with the HAMD score (r = 0.218, P ＜ 0.01). The results of multivariate logistic regression analysis showed that the age, disease duration, TNF-α and physical abuse factors were the influencing factors of the onset of adolescent depressive disorder in childhood (OR = 0.141, 1.170, 0.281 and 1.232, P ＜ 0.01).

Conclusions There are differences in the TNF-α levels between adolescent patients with depressive disorders who develop the disease in childhood and those who develop it in adolescence, and the TNF-α is age-related.