The level of TGF-β, measured 3 months after surgery, correlates negatively with BDI depression scale scores obtained in the follow-up study a month after SCS (rs = −0.634; p = 0.027)—higher intensity of depressive symptoms in BDI one month after surgery correlates with lower TGF-β level in measurement 3 months after SCS. The gene discussed is TGFB1; the disease is major depressive disorder.