FKBP5 and depressive symptom measurement: This team examines COC effect on the HPA axis. FKBP5 encodes a protein regulator of the HPA axis. This SNP is associated with alterations in the expression level of FKBP5, the T allele is associated with increased expression and depression risk when combined with childhood trauma. Because OCs are associated with higher levels of circulating cortisol, the authors test if the combination of Ocs and the SNP cause stress-like alterations in gene expression.