The Posttraumatic Stress Disorder Checklist (PCL; Weathers, Litz, Herman, Huska, & Keane, 1993; Weathers, 2008) is one of the most widely used self-report measures of posttraumatic stress disorder (PTSD). The PCL includes 17 items that correspond to the PTSD symptom criteria in Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV; American Psychiatric Association, 1994). Nearly 25 years of research have supported the validity of the PCL to assess PTSD in a wide range of populations (Wilkins, Lang, & Norman, 2011).
The PCL was recently revised for DSM-5, and the new version (PCL-5; Weathers, Litz, et al., 2013) includes several major changes. First, item content was revised to be compatible with DSM-5 PTSD symptom criteria. This involved adding three items to assess the three new PTSD symptoms and rewording existing items to reflect changes to existing PTSD symptoms. Second, the rating scale was revised from 1-5 to 0-4 so that the lowest possible total PCL-5 score is 0 rather than 17 on the PCL. The main implication of these first two changes is that clinicians and investigators will need to become accustomed to different scoring ranges and cutoffs for the PCL-5.
Third, instead of the three versions of the PCL (military, civilian, and specific, or PCL-M, PCL-C, and PCL-S), there is only one version of the symptom items for the PCL-5, which follows the PCL-S in referring to the index event as “the stressful event.” Last, there are three versions of the PCL-5, but they differ only in how Criterion A is assessed. The first version does not assess Criterion A. The second version defines Criterion A and provides examples of stressful events, asks individuals to identify their worst event, and then assesses whether the worst event meets Criterion A. The third version includes the Life Events Checklist for DSM-5 (LEC-5; Weathers, Blake, et al., 2013) and a more detailed assessment of Criterion A.
The aim of our research was to investigate the psychometric properties of the PCL-5 in two studies of trauma-exposed college students (N=278 for Study 1, N=558 for Study 2). Study 1 compared the PCL-5 to the PCL and two other self-report PTSD measures. Study 2 was a replication of Study 1. Overall, our results indicate that the PCL-5 is very strong psychometrically, with excellent test-retest reliability, internal consistency, and convergent and discriminant validity. Also, confirmatory factor analyses (CFA) revealed that a 6-factor model provided the best fit for the symptom structure of the PCL-5. This is inconsistent with the rationally derived DSM-5 symptom clusters, but consistent with other recent CFA studies (Liu et al., 2014).
Further, the PCL-5 was equivalent to the PCL with regard to its psychometric performance. This equivalence, along with the fact that 9 of 20 PCL-5 items are unchanged from the PCL and 3 more are only slightly reworded, suggests that the PCL-5 has substantial backward compatibility with the PCL. Finally, although we did not compare the PCL-5 to a diagnostic interview, we did calibrate the PCL-5 against the PCL by identifying cutoff scores on the PCL-5 that best predicted commonly used cutoffs on the PCL. These analyses revealed that PCL-5 scores of 28, 31, and 37 best predicted PCL scores of 40, 44, and 50, respectively. More research is needed to verify these PCL-5 cutoffs, but in the interim they can be used as provisional equivalents for their corresponding PCL scores.
To our knowledge, this is the first comprehensive psychometric evaluation of the PCL-5 in a mixed civilian trauma sample. Taken together, the two studies we conducted indicate that the PCL-5 is a psychometrically sound self-report measure of the DSM-5 PTSD symptom criteria and is closely comparable to the PCL. Like the PCL, the PCL-5 can be used for a variety of clinical and research assessment tasks, including quantifying PTSD symptom severity, measuring the underlying construct of PTSD, establishing a provisional PTSD diagnosis, and estimating prevalence of PTSD. Although our research only addresses the first two tasks, the strong comparability of the PCL-5 with the PCL suggests that the PCL-5 will prove to be useful for the other tasks as well.
Discussion Questions:
- What are the major changes for the PCL-5, and what are the implications of these changes for clinicians and investigators?
- How does the PCL-5 compare to the PCL in terms of reliability and validity?
About the Authors:
Christy Blevins, Ph.D., is a psychologist at the VA Portland Health Care System. Her clinical and research interests include assessment and treatment of posttraumatic stress disorder and other traumatic stress responses.
Frank Weathers, Ph.D., is a Professor of Psychology at Auburn University. His research interests include the assessment and treatment of posttraumatic stress disorder and psychometric evaluation of psychological assessment instruments. He is co-author of the PTSD Checklist and Clinician-Administered PTSD Scale, and recently led the effort to revise these measures for DSM-5.
Reference Article:
Blevins, C. A., Weathers, F. W., Davis, M. T., Witte, T. K., & Domino, J. L. (2015). The Posttraumatic Stress Disorder Checklist for DSM-5 (PCL-5): Development and Initial Psychometric Evaluation. Journal of Traumatic Stress, 28(6), 489-498. doi: 10.1002/jts.22059
References:
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American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Washington, DC: Author.
Liu, P., Wang, L., Cao, C., Wang, R., Zhang, J., Zhang, B., …, Elhai, J. D. (2014). The underlying dimensions of DSM-5 posttraumatic stress disorder symptoms in an epidemiological sample of Chinese earthquake survivors. Journal of Anxiety Disorders, 28, 345-351. doi: 10.1016/j.janxdis.2014.03.008
Weathers, F.W. (2008). Posttraumatic Stress Disorder Checklist. In G. Reyes, J. D. Elhai, & J. D. Ford (Eds.), Encyclopedia of psychological trauma (pp. 491-494). Hoboken, NJ: Wiley.
Weathers, F. W., Litz, B. T., Herman, D. S., Huska, J. A., & Keane, T. M. (1993). The PTSD Checklist: reliability, validity, and diagnostic utility. Paper presented at the annual meeting of the International Society for Traumatic Stress Studies, San Antonio, TX.
Weathers, F.W., Litz, B.T., Keane, T.M., Palmieri, P. A., Marx, B. P., & Schnurr, P.P. (2013). The PTSD Checklist for DSM-5 (PCL-5). Instrument available from the National Center for PTSD at www.ptsd.va.gov.
Weathers, F.W., Blake, D.D., Schnurr, P.P., Kaloupek, D.G., Marx, B.P., & Keane, T.M. (2013). The Life Events Checklist for DSM-5 (LEC-5). Instrument available from the National Center for PTSD at www.ptsd.va.gov.
Wilkins, K. C., Lang, A. J., & Norman, S. B. (2011). Synthesis of the psychometric properties of the PTSD Checklist (PCL) military, civilian, and specific versions. Depression and Anxiety, 28, 596-606. doi:10.1002/da.20837