ADGRG1 and major depressive disorder: To further examine the potential function and regulation of Gpr56 in depression and antidepressant response, we conducted studies in animals, using the unpredictable chronic mild stress (UCMS) paradigm, a well validated murine model of depression5, followed by treatment with fluoxetine, a standard SSRI, to model antidepressant effects (Fig. 2a).