Short answers, pulled from the story.
The American Psychiatric Association officially added post-traumatic stress disorder to its third edition of the Diagnostic and Statistical Manual in 1980. This decision followed decades of observing soldiers returning from Vietnam with symptoms that did not fit existing diagnoses.
Research indicates approximately 30% of the variance in susceptibility to PTSD is caused by genetics alone. Neuroscientist Dr. Rachel Yehuda studied how psychological trauma travels across generations through specific stress genes like FKBP5 linked to PTSD development.
In the United States about 3.5% of adults have post-traumatic stress disorder in a given year while 9% develop it at some point in their lives. The National Comorbidity Survey Replication estimated lifetime prevalence among adult Americans is 6.8%.
Eye movement desensitization and reprocessing developed by Francine Shapiro involves voluntary rapid eye movements while focusing on memories about particular trauma. A 2018 systematic review found moderate strength of evidence supporting EMDR efficacy for reduction in PTSD symptoms and loss of diagnosis.
The DSM-III published in 1980 classified post-traumatic stress disorder as an anxiety disorder before reclassifying it as a trauma-and-stressor-related disorder in the DSM-5 released in 2013. Symptoms must persist longer than one month after the inciting traumatic event to be classified as PTSD rather than acute stress disorder.