Inflammatory cytokines and functional impairment in drug-free subjects with mood disorder

OBJECTIVE: To assess the association between peripheral levels of inflammatory cytokines and functional impairment in subjects with Bipolar Disorder (BD), Major Depressive Disorder (MDD) and population controls. METHODS: This was a cross-sectional study with a matched sample of drug-free young adults with BD (n=48), MDD (n=48) and population controls (n=48). Mood disorder was confirmed by a certified psychologist using the Structured Clinical Interview for DSM-IV (SCID-I). Functional impairment was assessed using the Functional Assessment Short Test (FAST). Serum levels of IL-6 and IL-10 were measured by ELISA. RESULTS: Peripheral levels of IL-6 and IL-10 were not significantly different between subjects with BD, MDD compared to controls. Higher levels of functional impairment were verified in subjects with BD and MDD compared to population controls (p≤0.001). In addition, IL-6 and IL-10 levels were positively correlated with functional impairment in subjects with BD (IL-6: r=0.349, p=0.016; and IL-10: r=0.351, p=0.016). CONCLUSION: Inflammatory dysregulation was associated with functional impairment among drug-free subjects with BD. This finding suggests that inflammatory dysregulation may be involved in the neuroprogression of BD.