Studies of FKBP5 show support for an interaction between negative/stressful environments and genotype (including the SNP rs1360780) predicting adverse mental health outcomes, such as PTSD, depression and suicidality (Appel et al., 2011; Binder et al., 2008; Koenen et al., 2005; Roy, Gorodetsky, Yuan, Goldman, & Enoch, 2010; Zimmermann et al., 2011). This evidence concerns the gene FKBP5 and post-traumatic stress disorder.