NPY and post-traumatic stress disorder: Biomarkers like neuropeptide-Y (NPY) and cortisol have been well-established as having significant associations to PTSD; in the case of both biomarkers, these relationships are compelling enough that they have been used in interventional studies using PTSD animal models and human participants (Aerni et al., 2004; Schemletzer et al., 2016; Speer et al., 2019; Nwofakor et al., 2020).