ROC curve analysis of optimal cutoff value of PTSD Checklist-Civilian Version for PTSD screening early after earthquake

Abstract

Objective To early assess post-traumatic stress disorder (PTSD) symptoms and study the optimal cutoff value of PCL-C for screening PTSD among victims of Wenehuan earthquake.Methods By random selection strategy,223 victims were measured by PTSD Checklist-Civilian Version (PCL-C).Then data were analyzed according to symptom criteria of DSM-IV PTSD,and the result of symptomatology analysis was taken as actual state variable of ROC curve and total score of PCL-C as the test variable.The point on ROC curve having the highest Youden Index was considered as the optimal cutoff value.Results Twenty-six percent of victims met symptom criteria of DSM-IV PTSD and 77.6% had at least one PTSD symptom.The most common three symptoms were upset when reminded (65.0%),intrusive recollection(63.2%),and hypervigilance(51.6%).The rarest two symptoms were irritability/anger (7.2%) and psychogenic amenesia(4.5%).Area under the curve (AUC)of ROC was 0.966±0.011 (95% CI:0.945 -0.988,P＜0.01).The point of 41 had the highest Youden Index of 0.815,and had a sensitivity of 0.948 and specificity of 0.867.Conclusion PTSD symptoms are common among victims in temporary settlements till the second week after Wenchuan earthquake,and 41 may be the optimal cutoff value of PCL-C for screening PTSD symptoms. Key words: PTSD; Psychological assessment; ROC curve