DRD2 and post-traumatic stress disorder: Recently Yuan et al., (2021) have shown that Taq1A polymorphism of the DA D2 receptor (D2R), where the T allele carriers of D2R Taq1A express lower D2R density, higher levels of neuroinflammation and hippocampal atrophy and this causes reduced hippocampal subfield volume of CA3 region and severe PTSD symptoms (Yuan et al. 2021).