Stress in early childhood different stages in early childhood. In the first stage, stress usually causes alarm. Next, in the second or appraisal stage, the child attempts to find meaning from the event. Stage three consists of children seeking out coping strategies. Lastly, in stage four, children execute one or more of the coping strategies. However, children with lower tolerance for stressors are more susceptible to alarm and find a broader array of events to be stressful. These children often experience chronic or toxic stress. Children from a lower socioeconomic status are more prone to exposure to all the early life stress listed above.
Epigenetics of anxiety and stress-related disorders triggered PTSD. "Nr3c1" is a gene that encodes a glucocorticoid receptor (GR) and contains many GR response elements. Early life stress increases methylation of the 1 promoter in this gene (or the 1 promoter analog in rodents). Because of its role in stress response and its link to early life stress, this gene has been of particular interest in the context of PTSD and has been studied in PTSD of both combat veterans and civilians. In studies involving combat veterans, those who developed PTSD had lowered methylation of the "Nr3c1" 1 promoter compared to those who did not develop PTSD.