One of the most-profound findings emerging from recent psychiatric genomic studies is the degree to which psychiatric disorders, as defined and classified based on conventional diagnostic nosologies, overlap at a genetic level35,36. To demonstrate this point for PTSD, we chose the largest (n = 150 K) and most successful (108 significant hits) PGC study to date conducted in schizophrenia27, and showed evidence of polygenic overlap with PTSD. For schizophrenia–PRS, the step of choosing the optimal p value threshold (P value thresholding) is skipped in order to avoid multiple testing burden. Instead, a threshold of nominal significance (PT = 0.05) has been shown to be the most predictive in the original publication27, and that threshold is used here.
