According to immune checkpoint gene differential analysis, we found that CD274, CTLA4, TIGIT, PDCD1LG2, PDCD1, LAG3 and HAVCR2 in ICD gene high expression group were higher than those of the ICD low expression group whereas SIGLEC15 was lower in ICD high group (Figure 6E). The gene discussed is PDCD1LG2; the disease is impulse control disorder.