Next, TRPML1 AcKO mice were subjected to a subthreshold social defeat stress (SSDS) experiment and performed to the SI test before and after SSDS to assess depression‐related stress vulnerability.[23, 27] We found that Ctrl mice spent a similar amount of time in the interaction zone after 3 days of SSDS as before SSDS. Here, MCOLN1 is linked to major depressive disorder.