Predicting depressive symptoms and psychological distress by circulating inflammatory mediators: A 16-month prospective study in Japanese white-collar employees.

Objective: Although increasing evidence suggests that depression/distress involves inflammatory processes, its potential sex differences and the temporal directions for this association remain elusive.

Methods: We examined the temporal association between serum inflammatory mediators and depression/distress as measured by the Center for Epidemiologic Studies Depression Scale (CES-D) and the Kessler Psychological Distress Scale (K6), in non-depressed working men and women (n = 61 and 43, respectively) by a 16-month prospective design.

Results: Fully-adjusted partial correlation analyses revealed that in men, a lower IFN-γ predicted subsequent increases in CES-D and K6 scores, while a higher TNF-α predicted increased K6 scores. In women, a higher IFN-γ predicted a subsequent increase in the CES-D score. CES-D and K6 scores did not predict inflammatory mediators at follow-up.

Conclusions: The finding suggests that inflammatory activation precedes depression/distress with distinct sex differences.