Performance characteristics of the PTSD Checklist in retired firefighters exposed to the World Trade Center disaster.

BACKGROUND: Since the World Trade Center (WTC) attacks on September 11, 2001, the Fire Department, City of New York Monitoring Program has provided physical and mental health screening services to rescue/recovery workers. This study evaluated performance of the self-report PTSD Checklist (PCL) as a screening tool for risk of posttraumatic stress disorder (PTSD) in firefighters who worked at Ground Zero, compared with the interviewer-administered Diagnostic Interview Schedule (DIS).
METHODS: From December 2005 to July 2007, all retired firefighter enrollees completed the PCL and DIS on the same day. Sensitivity, specificity, receiver operating characteristic (ROC) curves, and Youden index (J) were used to assess properties of the PCL and to identify an optimum cutoff score.
RESULTS: Six percent of 1,915 retired male firefighters were diagnosed with PTSD using the DIS to assess DSM-IV criteria. Depending on the PCL cutoff, the prevalence of elevated risk relative to DSM-IV criteria varied from 16% to 22%. Youden index identified an optimal cutoff score of 39, in contrast with the frequently recommended cutoff of 44. At 39, PCL sensitivity was 0.85, specificity was 0.82, and the area under the ROC curve was 0.91 relative to DIS PTSD diagnosis.
CONCLUSIONS: This is the first study to validate the PCL in retired firefighters and determine the optimal cutoff score to maximize opportunities for PTSD diagnosis and treatment.