Tuesday, August 14, 2012
A consortium of U.S. psychiatrists, neurobiologists, data scientists, and more will pool resources in an effort to find a better means of diagnosing and potentially treating post-traumatic stress disorder (PTSD), a condition that can lead to debilitating anxiety or depression as well as cardiovascular disease.
Nearly eight million adults in the United States suffer from PTSD. War veterans are affected at a higher rate than the rest of the population, but civilians who are assaulted, survive a severe accident, or suddenly lose a loved one are also at risk. While there are treatments, clinicians have to use trial and error to determine whether medication, psychological therapy, or a combination will work best, and in some cases none of these strategies are effective.
The consortium plans to study both civilians and military personnel who have recently been in automobile accidents (some 9 percent of American accident survivors develop PTSD, according to the National Center for PTSD). The idea is to enroll people before symptoms begin to appear, so that researches can study how and in whom the disorder unfolds. The consortium will draw from genetic data, brain imaging, physiological measurements, and more to try to identify patterns that can be used to diagnose the disease and potentially improve treatment.
"The overall response rate is only about 50 percent, and there tend to be relapses," says Roger Pitman, a PTSD expert at Massachusetts General Hospital, who is leading the clinical arm of the consortium. "We may be able to develop patterns of biological abnormalities that will help to predict which treatment a person is most likely to benefit from."
PTSD is currently diagnosed solely on the basis of clinical interviews, and patients sometimes misrepresent their feelings, often because they are trying to avoid the memories and emotions associated with their trauma. Nearly half of PTSD patients are not identified, by some estimates.
"Every case of PTSD is unique, and how a person responds to trauma depends on the individual's previous experiences, stress coping mechanisms, and social support, as well as their genetics and hormones," says consortium member David Diamond, a neuroscientist at the University of South Florida and the Veteran Affairs Hospital in Tampa. "We now understand that all of these factors interact with the traumatic experience to leave its mark on its brain," he says. Although research has shown that physical phenomena such as the brain's response to stressful stimuli can be different in PTSD patients and healthy subjects, the consortium wants to go further.
"The goal is to develop quantitative biomarkers, such as from a blood test, urine analysis, or fMRI, that can be used to determine objectively if someone has PTSD," says Len Polizzotto, Draper's vice president in charge of the program. The markers could also help reveal whether treatment is working, he says.
Consortium member Jennifer Vasterling, a clinical investigator and chief of psychology at the Veterans Affairs Boston Healthcare System, says that long-term study could one day guide doctors in preventing symptoms from developing. "If you can look at biological features, psychological features, social features, and see what differentiates those who become symptomatic from those who don't, it gives you some idea where to go with preventative interventions," she says.
In addition to studying human participants, the consortium will also conduct animal studies to learn more about the molecular and cellular changes associated with the condition. "We have good reason to believe that stress in life changes your DNA, which makes it more difficult to produce proteins that nurture the brain," says Diamond, whose work with rats will give the consortium a look at how early-life stress affects the development of PTSD later in life.
Draper Labs, a nonprofit contract research and development organization in Cambridge, Massachusetts, that works in fields ranging from space systems to medicine, will integrate and analyze the disparate data to tease out useful information.
"The Draper Initiative gives us an opportunity to put all that we know together, within single patients and then in large groups of patients, so we can then back-engineer what your biological vulnerability contributes in combination with other biologic vulnerabilities or protective factors to predict either risk for PTSD or capacity to recover," says Ann Rasmusson, a psychiatrist and neuroendocrinologist at VA Boston and the Boston University School of Medicine. "Why keep doing little studies in small populations and not put all the pieces together?"