Because it was reported that delirium is associated with brain regions that play an important role in executive functions (e.g., frontal lobes, diencephalon), memory (e.g., hippocampus, BLA), and attention (e.g., parietal cortex, cerebellum) [19], neurotransmitters including NE, DOPAC, HVA, 5-HIAA and 5-HT1A in hippocampus, amygdala, prefrontal cortex and striatum were measured. This evidence concerns the gene HTR1A and delirium.