substantial proportion of men were from military cohorts and most women were civilian samples, while the UKB cohort had few to no participants exposed to military-related trauma (Nievergelt et al., 2019). Other sample differences include measurement/diagnosis of the PTSD phenotype (i.e., UKB PTSD status was determined with a brief self-report survey screen, as compared to the typical PGC-PTSD samples from PTSD-focused studies which include more diagnostic interviews), as well as power (i.e., sample size for UKB was substantially larger than PGC1.5) and heterogeneity (i.e., age differences across samples, with UKB being on average older than the PGC1.5 samples). All will have notable impacts on both heritability and genetic correlation estimates. Planned analyses as samples continue to grow include examination of detailed trauma and phenotypic information and their impact on measurement variability and heritability estimates (Nievergelt et al., 201).
