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Washington University School of Medicine, the University of Oklahoma and the Oklahoma State Department of Health have found that almost half suffered from psychiatric disorders in the months after the explosion. And the researchers were able to identify the symptoms that indicated the need for treatment.
In the Aug. 25 issue of the Journal of the American Medical Association, the investigators reported that 45percent of the survivors surveyed had psychiatric problems in the six months following the bombing. Just over 34 percent had post-traumatic stress disorder (PTSD).
"This tragic event was extremely severe both in scope and intensity," said principal investigator Carol S. North, M.D., associate professor of psychiatry at the medical school. "Over the years, our group has studied survivors of 13 different disasters, and the 34 percent rate of post-traumatic stress disorder after the Oklahoma City bombing is the highest in any of the studies we've done to date."
Part of the reason might have been the magnitude of the disaster. The bombing of the Alfred P. Murrah Federal Building killed 167 people, including 19 children. Another 684 people were injured. More than 800 structures in the area were either demolished or damaged, and the estimated property losswas $625million.
For this study, the investigators randomly selected 255 people from a confidential registry of 1,098 survivors maintained by the Oklahoma State Department of Health. Some were unreachable, and others refused to be interviewed, so 182 eventually were surveyed, using a structured interview called the Diagnostic Interview Schedule/Disaster Supplement, which assesses the mental health of disaster survivors and their disaster experience. The disaster supplement was developed by Washington University psychiatric epidemiologists Lee N. Robins, Ph.D., professor of psychiatry, and the late Elizabeth M. Smith, Ph.D. It was further revised and developed by Smith and North to assess the mental health of disaster survivors.
Of the survivors interviewed, 87 percent were injured in some way by the blast, and 82 percent saw someone injured or killed. Almost half (46 percent) reported thinking they were going to die at the time of the explosion, and 43percent lost a family member or friend. Of the 182 survivors surveyed, 92 percent knew someone who was injured or killed in the bombing. The survivors were interviewed an average of six months after the bombing.
Post-traumatic stress disorder is the classic psychiatric disorder seen in disaster survivors, and some symptoms occur in just about everyone, but an official diagnosis of PTSD requires several things.
First, a person must be exposed to an event that threatens life or limb: an accident, an explosion, combat or some other threatening circumstance. After exposure to such an event, mental health professionals look for three groups of symptoms that comprise PTSD.
The first group involves intrusive re-experience symptoms -- these include flashbacks and nightmares about the event. Another group involves hyperarousal symptoms, including feeling jumpy, having trouble sleeping or being startled easily. The remaining set involves avoidance and numbing symptoms. They include not wanting to think about an event, feeling distant and feeling numb or isolated from people. For an official diagnosis of PTSD, those symptoms must linger for at least a month and cause distress or problems in daily life.
The experience of some post-traumatic stress symptoms was nearly universal. Almost all survivors had flashbacks, nightmares or other intrusive reexperience symptoms. Hyperarousal symptoms also were common.
The least common PTSD symptoms also were the best predictors of the disorder. Survivors with at least three avoidance and numbing symptoms had an eventual diagnosis of PTSD 94percent of the time.
"Therefore," North said, "we recommend that disaster intervention workers be alert for avoidance and numbing symptoms because they are most predictive of post-traumatic stress disorder, for which referral for psychiatric evaluation is needed." Other survivors, she said, "tend to be distressed and hyperaroused and to have intrusive reexperience, but this doesn't mean that they're psychiatrically ill. Those symptoms may represent a normal or understandable response to abnormal events."
Although North thinks that the scope of the Oklahoma City bombing makes it difficult to compare with other disasters, she believes some important implications emerge from this study. First, because virtually all the cases of PTSD started almost right away, it is possible to begin to identify survivors with PTSD almost immediately. In addition, since most people who developed any psychiatric disorder also developed PTSD, concentrating on diagnosis of PTSD could identify those most likely to need psychiatric care.
The study also found that without avoidance and numbing, the nearly universal PTSD symptoms of intrusive reexperience and hyperarousal were not necessarily associated with later serious problems. Although survivors with those symptoms might benefit from reassurance and support, most will not require psychiatric intervention.
"There are two things for mental health providers to think about after a disaster, and our data on the Oklahoma City bombing reaffirm these," North said. "One is that some people become psychiatrically ill, but the other is that the majority of people do not. Most of them may have unpleasant symptoms and feelings and experiences, but that doesn't mean that they're ill."
