Spalletta et al. believe that the occurrence of PSD may be related to immune activation, leading to increased secretion of cytokines, and proposed a “cytokine hypothesis.” After stroke, astrocytes and microglia in the central nervous system produce cytokines and their receptors, including IL-1, IL-6, TNF-α, and IFN-γ. The gene discussed is IL1B; the disease is Stroke.