In recent years, IL-33 has been found to be involved in various disorders of the central nervous system (CNS), including multiple sclerosis (MS) (5, 6), infection (7, 8), ischemic stroke (9, 10), traumatic brain injury (TBI) (11, 12), spinal cord injury (SCI) (4, 13), brain tumorigenesis (14, 15), and mental disorders (16) (Figure 2). Here, IL33 is linked to mental disorder.