Certain people may be at increased risk of developing post-traumatic stress disorder (PTSD) long after exposure to a traumatic event, a study suggests.
PTSD typically arises in the months after a trauma or highly stressful experience like wartime combat, rape, assault or natural disaster. In some cases, however, onset of the disorder is delayed, becoming apparent years later.
In the new study, published in the journal Social Psychiatry & Psychiatric Epidemiology, researchers followed nearly 1,700 people who had lived in New York City during the September 11 attacks on the World Trade Center.
Study participants were evaluated for symptoms of PTSD one and two years after the disaster.
Nearly 92 percent of study participants showed no signs of PTSD at either time point, while 3 percent had the disorder at the first-year evaluation but not at the year two, and about 1 percent had symptoms at both one and two years.
On the other hand, just over 4 percent had PTSD at the second evaluation only, report Dr. Joseph A. Boscarino of the Geisinger Clinic in Danville, Pennsylvania, and Dr. Richard E. Adams at Kent State University, Ohio.
The researchers found that people with generally low self-esteem, relatively more negative life experiences – such as divorce or the death of a close family member – or a history of other traumas were at increased risk of delayed PTSD.
In addition, Hispanic and foreign-born New Yorkers were at greater risk than other ethnic groups and native-born residents, respectively.
“PTSD onset and course is complex and appears to be related to trauma exposure, individual predispositions, and external factors not directly related to the original traumatic event,” write Boscarino and Adams.
The findings could have implications for today’s military veterans, Boscarino said in a written statement.
“This country,” he said, “needs to be prepared to deal with veterans who could be experiencing war-related mental health stress years after combat.”
SOURCE: Social Psychiatry & Psychiatric Epidemiology, online May 6, 2009.