Furthermore, MAO-A deficiency results in blunted neuroendocrine responses to major stressors in humans and rodents (Brunner et al., 1993; Cases et al., 1995; Popova et al., 2006; Godar et al., 2011; Bortolato et al., 2013), as well as reduced extinction of aversive stimuli, a primary symptom in PTSD (Kim et al., 1997; Parsons and Ressler, 2013). Here, MAOA is linked to post-traumatic stress disorder.