A systematic review by Horn et al. (2018), including 26 studies in the most methodologically rigorous stage, reported a significant but attenuated relationship between circulating CRP concentrations and depression, with a small effect size (r = 0.05) after adjusting for confounding variables such as age, sex, obesity, and others [9, 18]. Here, CRP is linked to obesity due to melanocortin 4 receptor deficiency.