The second optional questionnaire, the MVP Lifestyle Survey, includes the PTSD Symptom Checklist (PCL; DSM-IV version)26, which asks respondents to report how much they have been bothered in the past month by symptoms in response to stressful life experiences. The PCL has 17 items, each scored on a 5-point severity scale (1 = “Not at All” though 5 = “Extremely”). The re-experiencing (REX) symptom domain is covered by 5 items (score range 5–25), the avoidance (AVOID) domain by 7 items (score range 5–35), and the hyperarousal (HYPER) domain by 5 items (score range 5–25), yielding an overall severity score (TOTAL) for the 17 items (score range 17–85). PCL items and their distributions in European Americans and African Americans are shown in Supplementary Table 1. After accounting for missing phenotype data, the final sample size for TOTAL was 186,689 in the EUR sample and 25,318 in the AFR sample.
