Past Issues

Psychosocial adverse conditions involving interpersonal processes are among
the strongest proximal risk factors for mood disorders. In this overview, I propose
a biologically plausible, multilevel theory that link experiences of social adverse
condition with internal neuroimmune mechanisms that drive pathogenesis for
mood disorders. Central to this neuroimmune mechanism hypothesis is a novel
axis of immune-to-brain bidirectional communication that infl uences mood and
behavior. Under social adverse conditions, sympathetic nervous system and hypothalamic–
pituitary adrenal axis can up-regulate myelopoiesis, monocyte traffi cking
and the expression of pro-infl ammatory genes encoding a conserved transcriptional
response to adversity (CTRA). Then elevated pro-infl ammatory cytokines
caused by central microglia activation and recruitment of monocytes to the brain
contribute to development of mood symptoms such as anhedonia, aggression, psychomotor
retardation and social-behavioral withdrawal. Because C-reactive protein
(CRP) determined by high-sensitivity methods currently is the most extensively
studied infl ammatory biomarker, therefore, this article provides a
comprehensive review of current knowledge concerning the current rôle of CRP in
neuroimmune mechanisms of mood disorders from a translational perspective.
The author suggests that the serum CRP levels is to be used as a biomarker for
mood statuses and a predictor of treatment response in mood disorders. The author
will also review the data of the clinical trials that used anti-infl ammatory medications
as adjunct pharmacotherapy in treating mood disorders. Finally, the author
concludes that the neuroimmune mechanisms might link mood disorders with
multiple system co-morbidities and sequential dementing change. Insights from
this theory may thus shed light on understanding of immune-to-brain bidirectional
communications, the rôle of psychosocial adverse conditions, the neuroimmune
mechanisms of co-morbidities and late life consequence in mood disorders.
Knowledge of the neuroimmune mechanisms may provide opportunities for preventing
and treating mood disorders by targeting infl ammation.