Similarly, as serotonin and norepinephrine reuptake inhibitors (SSRI and SNRI) remain the first line pharmacotherapy for PTSD, and numerous candidate gene studies have identified a link between variants in serotonin related genes, including HTR2a (27, 28), our observation of differential expression of HTR2a is consistent with the previous literature and support for this neurotransmitter system in the consequences of threat and trauma exposure. This evidence concerns the gene HTR2A and post-traumatic stress disorder.