In study after study, several treatments have been shown to work in treating Post Traumatic Stress Disorder. One of them, an approach called "prolonged exposure therapy," is effective about 80 percent of the time.
But new research claims that the majority of those suffering PTSD are not receiving this therapy.

The University of Pennsylvania's Edna Foa, one of the world's leading trauma researchers, developed prolonged exposure therapy 20 years ago. In simple terms, it exposes patients to triggers that flood them with memories of their trauma, and coaches them to alter their reactions.

Though Foa's approach has been validated in international and large-scale studies, her latest research shows that it's still not really being used.

Foa says therapists may be reluctant to embrace prolonged exposure because it may feel rigid.

"You have an agenda and you have to follow that agenda, and you have to be disciplined, and the patient has to be disciplined," explained Foa.

Psychologist Seth Gillihan of Haverford College co-authored the new study. He says most PTSD patients receive talk therapy and other treatments that have not been researched enough to show that they work in treating this disorder.

Gilihan says "seeing is believing" for many therapists who may be reluctant to change their approach.

"Once clinicians have first-hand experience of how effective these treatments are, then they become excited about the treatments and willing to use them and unwilling to use something that's not going to be as effective," he said.

Getting widespread adoption of successful treatments is a challenge in the mental health field, Foa said. She says she has had success, however, in the Veterans Affairs system, where close to 5,000 therapists have been trained on this approach.

Foa says she is now studying how to best train therapists and get health-care systems to adopt evidence-based treatments.