Cores 2017-06-03T01:25:31+00:00

Diagnosis and Trauma Exposure Harmonization Core

The harmonization of measures of trauma exposure across studies is an additional complication for PTSD genetics research. Though the DSM offers a broad definition of the types of events known to cause PTSD, there is no uniform or generally agreed-upon framework for categorizing or measuring them. A variety of self-report measures of trauma exposure are represented among PGC–PTSD studies. Most consist of a list of events that meet the DSM-IV PTSD Criterion A1 trauma definition including exposure to sexual or physical assault, combat or warfare, sudden death of friend/loved one, and so on. Most also make it possible to re-classify events for harmonization purposes into broader categories such as childhood vs adult trauma, or interpersonal versus non-interpersonal trauma, or to compute a measure of total trauma load.

Statistical Core

Standardized quality control procedures and GWAS analysis based on the PGC GWAS analysis pipeline will be used. Our primary analysis will be a GWAS meta-analysis of PTSD followed by a GWAS of PTSD severity, both controlling for potential sources of bias as well as trauma-exposure variables.

Patient Stratification Core

Psychiatric research including GWAS in the PGC have been performed primarily using subjects of European ancestry. In contrast, PTSD studies have recruited subjects primarily from high-risk populations, such as combat-veteran cohorts, or in urban areas with high rates of violent crime, and thus PGC–PTSD samples include a large proportion of subjects of African-American and Hispanic/Latino ancestry. GWAS on such heterogeneous and admixed samples require additional considerations. Our pipeline will account for greater population stratification between and within PGC–PTSD groups compared with the typical PGC analysis. Both within-ancestral group and cross-ancestral group meta-analysis will be performed.