Disasters expose unselected populations to traumatic events and can be used to study the mental health effects. The Oklahoma City, Okla, bombing is particularly significant for the study of mental health sequelae of trauma because its extreme magnitude and scope have been predicted to render profound psychiatric effects on survivors. To measure the psychiatric impact of the bombing of the Alfred P. Murrah Federal Building in Oklahoma City on survivors of the direct blast, specifically examining rates of posttraumatic stress disorder (PTSD), diagnostic comorbidity, functional impairment, and predictors of postdisaster psychopathology. Of 255 eligible adult survivors selected from a confidential registry, 182 (71%) were assessed systematically by interviews approximately 6 months after the disaster, between August and December 1995. Diagnosis of 8 psychiatric disorders, demographic data, level of functioning, treatment, exposure to the event, involvement of family and friends, and physical injuries, as ascertained by the Diagnostic Interview Schedule/Disaster Supplement. Forty-five percent of the subjects had a postdisaster psychiatric disorder and 34.3% had PTSD. Predictors included disaster exposure, female sex (for any postdisaster diagnosis, 55% vs 34% for men; chi2 = 8.27; P=.004), and predisaster psychiatric disorder (for PTSD, 45% vs 26% for those without predisaster disorder; chi2 = 6.86; P=.009). Onset of PTSD was swift, with 76% reporting same-day onset. The relatively uncommon avoidance and numbing symptoms virtually dictated the diagnosis of PTSD (94% meeting avoidance and numbing criteria had full PTSD diagnosis) and were further associated with psychiatric comorbidity, functional impairment, and treatment received. Intrusive reexperience and hyperarousal symptoms were nearly universal, but by themselves were generally unassociated with other psychopathology or impairment in functioning. Our data suggest that a focus on avoidance and numbing symptoms could have provided an effective screening procedure for PTSD and could have identified most psychiatric cases early in the acute postdisaster period. Psychiatric comorbidity further identified those with functional disability and treatment need. The nearly universal yet distressing intrusive reexperience and hyperarousal symptoms in the majority of nonpsychiatrically ill persons may be addressed by nonmedical interventions of reassurance and support.
