IL1B and post-traumatic stress disorder: According to Jones and colleagues, the severe stressor (stress‐enhanced fear learning) increases IL‐1β immunoreactivity and mRNA expression in the dentate gyrus of the dorsal hippocampus (DH), leading to posttraumatic stress disorder (PTSD) in mice, and the treatment of PTSD reduces IL‐1 expression in the DH region as a result of severe stress.38