Trait sensitivity to negative feedback determines the effects of chronic stress and chronic mirtazapine treatment on anxiety and stress-coping strategies in rats.

In this study, we examined whether trait sensitivity to negative feedback (NF) can interact with the effects of chronic stress and antidepressant treatment on anxiety and stress-induced coping strategies in rats. Results of the conducted experiments indicated that animals displaying trait insensitivity to NF were more prone to develop stress-induced anxiety than their NF-sensitive conspecifics. Moreover, an analysis of the behavioral patterns displayed by the NF-insensitive animals during the forced swim test (FST) revealed complementary (anxiety-driven) effects of trait sensitivity to NF on the strategy of coping with an acute, stressful situation. Finally, an analysis of the interactions between NF sensitivity and the effects of antidepressant drug - mirtazapine - revealed that in animals subjected to chronic stress, the effects of the drug on anxiety and coping strategies differ significantly between animals classified as NF insensitive and NF sensitive. The present results suggest that NF sensitivity screening could be potentially used to determine individual vulnerability to development of affective disorders and effectivity of their treatment.