IL2 and major depressive disorder: IL-2 was not significantly altered after treatment in schizophrenia patients (g: −0.18; CI −1.00 to 0.65; p = 0.676; I2 = 91%) nor after treatment in MDD patients (g: −0.98; CI −3.82 to 1.86; p = 0.50; I2 = 97%).