Choosing Assessment Instruments for Posttraumatic Stress Disorder Screening and Outcome Research

Posttraumatic stress disorder (PTSD) is a clinical syndrome that emerges following direct or indirect exposure to a traumatic event that includes actual or potential death, serious injury, or sexual violence (American Psychiatric Association [APA], 2013). Some of the characteristic symptoms of PTSD include persistent reexperiencing of the event, avoidance of stimuli associated with the event, and heightened physiological arousal. Although the duration of symptoms may vary, individuals with PTSD may experience a protracted clinical course, with some episodes lasting, on average, more than 11 years (Pietrzak, Goldstein, Southwick, & Grant, 2011). Although epidemiological studies have reported the lifetime prevalence of PTSD to range from 4.8% to 6.4% (Blanco et al., 2013; Pietrzak et al., 2011), some researchers have anticipated an increase in prevalence rates in the next few decades because of recent prolonged U.S. military engagement (Schell & Marshall, 2008). Complicating the identification and treatment of PTSD is its high comorbidity with other disorders, with some estimates indicating that individuals diagnosed with PTSD are 80% more likely to meet the diagnostic criteria for another disorder (APA, 2013). Especially when comorbid with depression and alcohol use disorders, a PTSD diagnosis may exacerbate the risk for suicide and is associated with high levels of severity in many psychosocial domains (Blanco et al., 2013; Lee, Liverant, Lowmaster, Gradus, & Sloan, 2014), thus making accurate assessment of this complex disorder imperative. Various instruments are used to assess PTSD, including self-report screening instruments and structured clinical interviews. Screening instruments can be administered by a mental health professional or completed by the client and generally aim to measure common PTSD symptoms. Some screening instruments may reflect diagnostic criteria and may provide a criterion score for diagnosis, although their use as a sole diagnostic tool is not recommended (Erford, 2013). Structured clinical interviews, often considered the gold standard, can be administered by mental health professionals or trained paraprofessionals (Steel, Dunlavy, Stillman, & Pape, 2011). Beyond examining the psychometric properties of various PTSD measurements, counselors should assess their usefulness in outcome research to provide additional information on their quality, thus facilitating accurate measurement. Counseling assessment and outcome research aims to determine the effectiveness of interventions used in counseling, as well as the potential for interventions to produce long-lasting treatment results. Erford et al. (2016) conducted a meta-analysis of 152 PTSD clinical trials from articles published in English between 1990 and 2012. Inclusion criteria were the delivery of any treatment intervention by a mental health professional designed to reduce PTSD symptoms in individuals meeting PTSD diagnostic criteria. The majority of studies included in the Erford et al. meta-analysis used standardized self-report or structured clinical interview PTSD measures, which allowed for the extensional analysis and review of those PTSD measures in our current study. The purpose of this article was to compare and contrast the six most commonly administered PTSD measures from Erford et al.'s (2016; see Table 1) meta-analysis by using the effect-size estimates to determine each PTSD instrument's usefulness in measuring treatment outcomes for PTSD. These six PTSD screening measures included the Clinician-Administered PTSD Scale (CAPS; Blake et al.. 1990), the Impact of Event Scale-Revised (IES-R; Weiss & Marmar, 1997), the Posttraumatic Stress Diagnostic Scale (PDS; Foa, 1995), the PTSD Checklist (PCL; Weathers, Litz, Herman, Huska, & Keane, 1993), the Mississippi Scale for Combat-Related PTSD (M-PTSD; Keane, Caddell, & Taylor, 1988), and the Structured Interview for PTSD (SI-PTSD; Davidson, Kudler, & Smith, 1990). …