Inflammation may underlie the link between major depressive disorder and RA.
References1. Vallerand IA, Lewinson RT, Frolkis AD, et al. Depression as a risk factor for the development of rheumatoid arthritis: a population-based cohort study. RMD Open. 2018;4:e000670. doi: 10.1136/rmdopen-2018-000670.2. Lewinson RT, Vallerand IA, Lowerison MW, et al. Depression is associated with an increased risk of psoriatic arthritis among patients with psoriasis: a population-based study. J Invest Dermatol. 2017;137:828-835.