IL-6 was correlated with the MFSI Emotional subscale (r = 0.75, p < 0.001, n = 18) and Total score (r = 0.82, p < 0.001, n = 18), the SF-36 Social Functioning scale (r = −0.71, p = 0.002, n = 16), the POMS Depression (r = 0.70, p = 0.001, n = 18) and Fatigue (r = 0.71, p < 0.001, n = 18) subscales and Total Mood Disturbance score (r = 0.77, p < 0.001, n = 17), MDASI Severity (r = 0.80, p < 0.001, n = 17), and VAS Fatigue (r = 0.71, p = 0.002, n = 16). This evidence concerns the gene IL6 and major depressive disorder.