The relevance of the endocannabinoid system in behavior is highlighted by expression of CB1 and PPAR-α in glutamatergic neurons of emotion-relevant areas that have been identified by brain imaging to be critical in PTSD (amygdala, hippocampus, frontal cortex) (Moreno et al., 2004; Lo Verme et al., 2005; Shin et al., 2006; D'Agostino, 2007; D'Agostino et al., 2009; Katona, 2009; Petrosino and Di Marzo, 2017). This evidence concerns the gene PPARA and post-traumatic stress disorder.