IJCNMH ARCpublishing

Issue: Issue 3 (2016) – Supplement 3

Review Article

The inflammatory perspective of depression in the context of chronic medical conditions

Sara Azevedo-Pinto, Susana Santos, Orlando von Doellinger, Mário Barbosa, and Rui Coelho
Background: The inflammatory hypothesis of depression implies that an unbalance of the immune system may trigger abnormal responses, affecting neural signalling mediators and the hypothalamic-pituitary-adrenal axis. This theory underlies a bidirectional hypothesis on the influence of depressive symptoms in the clinical course of chronic inflammatory disorders (CID), as well as in the genesis of mood disturbances. We aim to review current knowledge on depressive disorders and chronic inflammatory diseases as comorbidities and the underlying pathophysiologic mechanisms. 
Methods: We performed a bibliographic search in PubMed, including publications released in the last 5 years, written in English, Portuguese and Spanish, containing the key words: depression, chronic inflammatory disorders, psoriasis, arthritis, inflammatory bowel disease and multiple sclerosis. 
Results: According to the literature, the incidence of depressive disorders is significantly higher in patients with CID. The medical conditions also present a worse clinical progression, with more frequent flares and decreased response to treatment. At the cellular and biochemical level, there is a deregulation of innate and adaptive immune responses, common to both medical and psychiatric pathologies, as well as an increase of the pro-inflammatory and acute phase reactants, with a inhibition of anti-inflammatory mechanisms. CID exert a major impact on the patients, at social, relational, functional and working levels, leading to decreased global performance, and enhancing several risk factors for depressive disorders. 
Conclusion: Besides the life stressing factors associated to CID, there are cellular and biochemical alterations triggering the dysfunction of the immune system, establishing a bridge with the pathophysiology of depressive disorders.

Keywords: Depression, Chronic inflammatory disorders, Psoriasis, Arthritis, Inflammatory bowel disease, Multiple sclerosis.

Special Issue on Inflammatory Demyelinating Diseases of the Central Nervous System

International Journal of Clinical Neurosciences and Mental Health 2016; 3(Suppl. 3):S11 
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