Diane Evans puts down the phone to remove her pecan pie from the oven in preparation for holiday festivities with her family. When she returns, she continues recounting her war terrors -- this time, the ones that came back to her in dreams: bloodied faces and dismembered bodies of soldiers and children covered in third-degree burns, patients she treated and some she watched die in Vietnam more than 40 years ago.
"They started to come back one by one," says Evans, 69, of the nightmares that started 13 years after she returned home from her one-year deployment in Vietnam from 1968 to 1969. "I would see the fire, and then I would wake up in a cold sweat."
Evans, who was 21 at the time of her deployment, worked for the U.S. Army Nurse Corps in two evacuation hospitals in Vung Tau and Pleiku.
Cases like Evans', in which post traumatic stress symptoms occur years after a traumatic event, are common, experts say. They say misconceptions about when symptoms present themselves can lead to misdiagnosis -- or no diagnosis at all -- stressing the importance of continued and repeated screening of veterans to ensure they don't fall through the cracks.
"We've kept moving the timeline as we've seen people develop symptoms decades later," says Dr. Elspeth Cameron Ritchie, professor of psychiatry at the Uniformed Services University of the Health Sciences in Maryland. "We do know that if you develop symptoms early, you are more likely to have them over time."
According to a recent study, almost 16 percent of female veterans who were stationed in Vietnam experienced post traumatic stress disorder symptoms within the past year. Around 8 percent who were stationed near Vietnam and around 9 percent who were stationed in the U.S. experienced PTSD symptoms within the past year. Most were 21- to 22-years-old at the time of enlistment, the study reported.
PTSD is a mental health condition that affects people who have experienced or witnessed a traumatic event, including war, sexual assault, natural disasters, accidents or abuse. It can develop at any age and affect anyone, according to the National Institute of Mental Health.
Symptoms include nightmares, intrusive thoughts, flashbacks, anxiety, depression and avoiding things that remind the person of the traumatic event.
"You see this gradual shrinking world as this person tries to avoid it," says Jeffrey Mann, clinical psychologist at Capital Institute for Cognitive Therapy in Washington, D.C. "They start to organize their life around their avoidance, even to the point of avoiding sleep because they have nightmares."
Sights, sounds and smells can trigger symptoms. TV footage from 9/11 triggered many memories for Vietnam veterans, says Ritchie, adding that they are at a higher risk of developing PTSD as they age and become more vulnerable.
Evans' PTSD was triggered when she visited the dedication of the Vietnam Veterans Memorial Wall in Washington on Nov. 13, 1982. She was 36. Seeing the names of fallen soldiers on the wall was her "Pandora's box," she says.
Evans founded the Vietnam Women's Memorial Foundation in Washington shortly after the wall's dedication, to provide support for other female veterans and to demand awareness of their contributions in the Vietnam War.
Between 5,000 and 7,500 women served in Vietnam. Almost 80 percent of them were nurses, according to a study published in JAMA Psychiatry. Another 2,000 were based in surrounding countries including Guam, the Philippines, Japan, Korea and Thailand, and 250,000 were stationed in the U.S.
Researchers involved in the study surveyed 4,219 female Vietnam veterans beginning in 2011 using mailed questionnaires and phone interviews. Veterans surveyed were active in Vietnam, in areas around Vietnam, and in the U.S. for at least 30 days. They screened for PTSD symptoms using the Women's Wartime Exposure Scale-Revised, which consists of a series of questions about their wartime experiences, like how often they were involved in mass casualty situations and whether they assisted someone who was dying. If they answered yes, they were asked more specific questions.
Women from the Vietnam era have been understudied, says Kathryn Magruder, a professor of psychiatry and public health sciences at the Medical University of South Carolina and lead author of the study. She says little is known about their wartime experiences and the effects PTSD will have on other health conditions as they age. "For some women, it was the first time they had spoken about any of these experiences."
Getting male or female veterans to speak up about their symptoms is one of the biggest challenges in identifying those who need help, mental experts say, because of a fear of showing weakness. This is especially true in the military's "toughen up" culture. And women serving in the military might be particularly reluctant to voice their condition, partly because they are outnumbered.
"For women, there is very much a desire to conform to that military culture … you are already a minority and there can be a tremendous pressure to conform, just to push it down and pretend it's not there," Mann says.
According to the Department of Veterans Affairs, five out of 10 women experience a traumatic event, and women are more than twice as likely to develop PTSD as males. They also have a higher risk of being sexually harassed or sexually assaulted in the military than men.
Certain symptoms are more common among women, according to the site, like jumpiness and avoiding things that remind them of the event, while men are more likely to experience anger and to use alcohol and drugs.
Female veterans interviewed say they were forgotten after the war, and that their experiences were considered less traumatizing than those of soldiers in combat.
"We didn't have a gun, but we would crawl on the floor when bombs were going off to be sure our patients were taken care of," says Joan Furey, 69, a nurse who worked in an intensive care unit in Pleiku, Vietnam, from 1969 to 1970. "You never picked up a weapon, but you certainly understood what it was like to think about dying." Furey has experienced PTSD symptoms on and off throughout her life since Vietnam, including depression and nightmares.
The condition could date back to World War I, to what was known as shell shock, says Andrew Wackerfuss, adjunct professor of military history at Georgetown University. "You can even see it in the label, that they understood it as a physical effect just as much or even more than a mental effect, having to do with the shock waves from artillery in the trenches in World War I."
Wackerfuss says after World War II and the Korean War, the culture was to avoid talking about PTSD because of a social expectation "to move on and not dwell on negative experiences," all of which could show signs of weakness.
PTSD first became recognized as a disorder in 1980, according to the National Institute of Mental Health.
Experts say further research and increased screening are essential as the science around PTSD evolves, including screening, diagnosis and treatment methods. They also say more widespread education in public health could help people identify it more frequently.
"We should acknowledge that problems can develop at various points in life and we don't fully understand how or why or when," says Michael Schoenbaum, senior adviser for mental health services, epidemiology and economics at the National Institute for Mental Health. "So we should be vigilant and we should have mechanisms in place so that if somebody does develop a problem like PTSD, we have a way of figuring this out and of identifying that somebody is suffering sooner rather than later."
PTSD is treated with cognitive processing therapy and prolonged exposure therapy, in which patients are exposed to the situations that cause them anxiety. Medicine is also used to treat it. Experts say some patients see significant improvement in eight to 10 weeks, but for others, it could be a lifelong condition.
According to the Department of Veterans Affairs, veterans using VA health care are screened annually for PTSD for the first five years after their service, then every five years. They began screening all veterans more than 10 years ago using the Primary Care PTSD Screen (PC-PTSD), a four-question survey.
But some experts say screening once a year is not enough.
Dr. Chuck Engel is one of them.
"I really do believe this is a chronic condition with a waxing and waning course," says Engel, a retired colonel and psychiatrist in the U.S. Army who now works as a senior health scientist at the Rand Corporation in Boston. "And I think it is far too easy to catch people in their good times when you're doing this once a year, especially in the military, where part of their job is to get in harm's way and they are regularly traumatized."
There is no clear consensus for how often people should be screened without further research, says Engel, but he says screening at least quarterly is reasonable.
Engel helped develop a collaborative care treatment known as the Re-Engineering Systems of Primary Care Treatment in the Military System, also known as Respect-mil, which was implemented in the U.S. Army in 2007 and expanded to over 90 military clinics around the world. It has also been implemented in some variation in the Air Force and the Navy.
Within the Army's collaborative care system, patients are screened every time they visit a primary care clinic, and provided ongoing treatment if the patient wants it. The nurse acts as a middleman between the patient and the psychiatrist, monitoring the patient's condition and helping them obtain a therapist if needed. Evans say implementing systems like Respect-Mil in primary care clinics beyond the military would better address the challenges in identifying and treating PTSD.
He says veterans often refuse to visit a specialist because of the stigma associated with mental disorders like PTSD, and using a collaborative care system like Respect-Mil ensures the patient has support if and when they need it.
Evans was sent home from Vietnam in 1969 with no post-deployment screening, but she says it likely would not have made a difference in identifying her PTSD.
"If I had been screened immediately following Vietnam, I probably would have answered 'no' to everything ... initial screening can be flawed in that the returning veteran is so much in shock or in a different frame of mind or denial," Evans said. "If they would continue that screening, it would determine the essence of the person's recovery, months or years later."