Although clinical and animal studies already identified PTSD candidate molecules like FK506 binding protein 5 (FKBP5) [1] and cyclin-dependent kinase 5 (CDK5) [2] and revealed gene x environment interactions [3]–[5] as well as alterations of the HPA axis [6] and sympathetic nervous system overdrive [7] to contribute to PTSD pathogenesis, the molecular pathomechanisms underlying this anxiety disorder still remain elusive. This evidence concerns the gene FKBP5 and post-traumatic stress disorder.