Interferon-α-induced depressive symptoms are related to changes in the cytokine network but not to cortisol

ObjectiveProinflammatory cytokines have the potential to activate the hypothalamo-pituitary-adrenocortical (HPA) axis, and HPA axis hyperactivity is also encountered in depression. Therefore, the induction of depressive symptoms by interferon-α (IFN-α) may be mediated by changes in the cytokine network and the HPA axis.MethodsIn 17 hepatitis C patients undergoing IFN-α treatment, depressive symptoms were measured using the Montgomery–Asberg Depression Rating Scale (MADRS). In addition, serum cytokine concentrations were measured. Saliva was collected five times over the course of a day in order to assess daily average cortisol (DAC) and awakening response. Assessments were carried out at baseline and six later time points after starting treatment.ResultsDuring treatment, the increases in the MADRS were significantly and positively correlated with soluble interleukin (IL)-2 receptor, tumor necrosis factor α (TNF-α), and IL-6. There were no significant associations between the DAC or cortisol awakening response with the MADRS score.ConclusionResults suggest a clear connection between IFN-α-induced depressive symptoms and cytokine concentrations, but not cortisol.