The Effect of Depression on Disease Activity and Treatment Response in Patients with Inflammatory Arthritis: Results from a Narrative Literature Review.

Background: Inflammatory arthritis refers to a group of diseases that have a common presentation of joint pain, stiffness, and inflammation. Meanwhile, major depressive disorder is a mental health disorder characterized by anhedonia and low mood. Inflammatory arthritis patients have high rates of major depressive disorder, estimated at being up to 38.8%. Depression leads to a significant reduction in patient's health-related quality of life, treatment adherence, and many other measures of health, both subjective and clinical. Purpose: This literature review explores the effect that depression has on treatment response for the drugs used in inflammatory arthritis. Methods: A systematic search using PubMed was conducted identifying articles which were each reviewed for relevance and eligibility. Results: Depression was negatively associated with treatment response to all classes of drugs used to manage inflammatory arthritis, with an increased disease activity and/or number of swollen/tender joints, as well as a reduced rate of remission being recorded for patients with depression compared to those without. However, this effect on treatment response was less clear when conventional synthetic Disease Modifying Anti-rheumatic Drugs were studied, possibly because their anti-inflammatory effects have wide impacts on the whole immune system, whereas biologic Disease Modifying Anti-rheumatic Drugs have very specific targets. Conclusion: Inflammatory arthritis patients have a significantly lowered response to most drugs when they have depression. Screening and treating depression may attenuate this association. It is recommended that further research focuses on screening for and treating depression in inflammatory arthritis patients.