Plasma levels of interleukin-6 and antidepressant response to Paroxetine in Chinese depressive patients.

This study aimed to investigate the correlation between interleukin-6 (IL-6) plasma levels and treatment outcomes of selective serotonin reuptake inhibitors in patients with major depressive disorder (MDD). A total of 104 patients (33 males and 71 females), aged 18 to 72 years, were enrolled. Peripheral blood samples were collected before treatment initiation (baseline) and eight weeks after oral paroxetine treatment. The Hamilton Depression Rating Scale (HAMD)-17 was used to evaluate the efficacy of paroxetine. Baseline plasma IL-6 levels were found to be significantly lower in patients who responded to treatment than in non-responders. A negative correlation was found between the HAMD-17 reduction rate and baseline IL-6 levels. Furthermore, associations were examined between HAMD-17 reduction rate in patients and other factors, such as IL-6 levels, sex, age, and body mass index. Baseline IL-6 was the only factor showing a significant impact on the reduction rate of HAMD-17 at week 8. These results suggest that plasma IL-6 level may be a promising biological marker for predicting the likely treatment response to paroxetine in individual patients with MDD.