Inflammatory Biomarkers for Mood Disorders - A Brief Narrative Review

The nervous system and the immune system interact consistently in the brain and peripheries. Inflammation in the brain not only alters the metabolism of neurotransmitters, but also causes network dysfunction, structural changes, and the development of mood symptomology in patients with mood disorders. In addition, the dysregulation of the neuroimmune axis in mood disorders drives multiple-system comorbidities. Furthermore, patients with low-grade inflammation are more likely to exhibit treatment resistance with both pharmacotherapy and non-pharmacotherapy.

The aim of this review was to examine the available data regarding not only evidence of inflammation in the pathophysiology of mood disorders and their comorbid conditions, but also potential inflammatory biomarkers of mood disorders.

Studies of the use of adjunct anti-inflammatory medications in mood disorders, and inflammatory biomarkers that may guide treatment outcomes in mood disorders, were summarized.

Studies have demonstrated that certain adjunct anti-inflammatory medications might help to improve mood symptoms and reduce comorbidities, and the baseline levels of inflammatory biomarkers, such as peripheral C-reactive protein (CRP), could be used to stratify the treatment outcome. All results suggested that the identification of peripheral and brain inflammatory biomarkers for the diagnosis, outcome prediction, staging, and stratification of interventions of mood disorders has emerged as an important area of translational research in psychiatry.

Inflammatory biomarkers could guide interventions and enhance treatment response in patients with mood disorders. The main challenge is that substantial complexities might hamper the attainment of this goal.