We found that the effect of the intervention (i.e., intranasal oxytocin) on the outcome (i.e., self-reported number of intrusions) differed significantly between participants with different covariate profiles (e.g., differences in SNP rs53576, especially with GG polymorphism, cortisol, HRV, and PTSD PRS; Fig. 3). This evidence concerns the gene OXT and post-traumatic stress disorder.