Baseline immune activation as a risk factor for the onset of depression during interferon-alpha treatment

Background: Major depression has been associated cross-sectionally with increased cell-mediated immune activation but causality has been cl difficult to establish. This study prospectively investigated the hypothesis that baseline level qf of immune activation predicts the development of depression during interferon-alpha (IRV-alpha) treatment.

Methods: Sixteen hepatitis C patients without psychiatric disorder underwent IFN-alpha treatinent. Proinflammatory and anti-infammtory cytokines were determined before starting treatment. Presence of a major depressive disorder (MDD) was assessed at baseline and several limes during treatment.

Results: Baseline soluble interleukin-2 receptor (sIL-2r), interleukin-6 (IL-6), and interleukin-10 (IL-10) concentrations were sign ficantlv increased in the five subjects that developed MDD during treatment compared with those that did not, with standardized effect sizes 1.08,./1.16, and 1.25, respectively, controlling for marijuana use, cigarette smoking, and baseline level of depressive symptoms.

Conclusions: Results suggest that increased nninune activation, rather than an epiphenomenon, is a causal risk.factorfir the development of MDD.