Ongoing episode of major depressive disorder is not associated with elevated plasma levels of kynurenine pathway markers

The obtained results do not support the hypothesis that MDD depressive episodes are associated with elevated activity in the kynurenine pathway. This suggests that the pathophysiology underlying depressive episodes in common MDD differs from that of interferon induced depression. Our results warrant further study of the interplay between the kynurenine pathway and the cytokine activation patterns in these conditions.