Diagnosis
The following PIE principles were in place for the "not yet diagnosed nervous" (NYDN) cases:

Proximity – treat the casualties close to the front and within sound of the fighting. Immediacy – treat them without delay and not wait until the wounded were all dealt with. Expectancy – ensure that everyone had the expectation of their return to the front after a rest and replenishment.United States medical officer Thomas W. Salmon is often quoted as the originator of these PIE principles. However, his real strength came from going to Europe and learning from the Allies and then instituting the lessons. By the end of the war, Salmon had set up a complete system of units and procedures that was then the "worlds best practice". After the war, he maintained his efforts in educating society and the military. He was awarded the Distinguished Service Medal for his contributions.Effectiveness of the PIE approach has not been confirmed by studies of CSR, and there is some evidence that it is not effective in preventing PTSD.US services now use the more recently developed BICEPS principles:

Brevity
Immediacy
Centrality or contact
Expectancy
Proximity
Simplicity

Between the wars
The British government produced a Report of the War Office Committee of Inquiry into "Shell-Shock", which was published in 1922.
The NICHD has worked alongside organizations like the World Health Organization to conduct research on the psychosocial development of children with part of their efforts going towards the support of mothers health and safety. Training and education services are offered through the NICHD to equip women and their health care providers with evidence-based knowledge on PPD.Other initiatives include the Substance Abuse and Mental Health Services Administration (SAMHSA) whose disaster relief program provides medical assistance at both the national and local level. The disaster relief fund not only helps to raise awareness of the benefits of having healthcare professionals screen for PPD, but also helps childhood professionals (home visitors and early care providers) develop the skills to diagnose and prevent PPD. The Infant and Early Childhood Mental Health Consultation (IECMH) center is a related technical assistance program that utilizes evidence-based treatments services in order to address issues of PPD. The IECMH facilitates parenting and home visit programs, early care site interventions with parents and children and a variety of other consultation-based services. The IECMHs initiatives seek to educate home visitors on screening protocols for PPD as well as ways to refer depressed mothers to professional help. Links to government-funded programs
National Child and Maternal Health Education Program
National Institute of Child Health and Human Development
Substance Abuse and Mental Health Services Administration
Infant and Early Childhood Mental Health Consultation Center

Psychotherapy
Therapeutic methods of intervention can begin as early as a few days post-birth when most mothers are discharged from hospitals.