Cytokines and depression: an analogic approach.

A growing body of evidence suggests that major depressive disorders may be accompanied by immune dysfunction and more particularly by an enhanced production of pro-inflammatory cytokines. The possible involvement of cytokines in depressive illness are based upon an analogic model. Pro-inflammatory cytokines are known to induce behavioral effects, and neuro-endocrine and immune activation similar to those observed in depression; these can be alleviated by antidepressant treatment. In this paper, we review research literature on the links between depressive illness and cytokine production and address further questions on this cytokine pathway. Further research is needed to see whether cytokines sustain specific depressive syndromes or whether cytokines induce depressive-like symptoms.