Method to Convert an 8-item PCL-5 Score to a Total PCL-5 Score: A Scaled Equation Analysis

The repeated assessment of PTSD symptom severity is a critical component of research and evidence-based interventions. PTSD is composed of 20 symptoms across four clusters. However, 20-item measures can be burdensome to administer frequently, especially in ecological momentary assessment (EMA) where multiple assessments are conducted per day. An abbreviated 8-item version of the PCL-5 was developed to obtain information about PTSD symptoms at reduced effort to the participant. However, the symptom severity scale by which symptoms can range between the abbreviated (0–32) and full (0–80) scales differ, which limits the interpretability of the abbreviated scale. The current study evaluated three different methods (a proportional, linear regression, and genetic programming model) to convert scores from the abbreviated measure to that of the full PCL. These equations were then compared across two testing samples to assess their accuracy and bias. The genetic programming and linear regression equation were superior to a proportional equation in both measures of accuracy and bias, with the genetic programming equation demonstrating less bias overall than the linear regression. Furthermore, the diagnostic utility of each method was found to be similar. These results provide a method to convert abbreviated PCL scores to that of the full scale, which increases the utility of this abbreviated scale.

Prevalence of Posttraumatic Stress Disorder Following the Earthquake in Iran and Pakistan: A Systematic Review and Meta-Analysis

Posttraumatic stress disorder (PTSD) is a common mental disorder following traumatic events. The present study was conducted to understand the prevalence of PTSD after the earthquake in Iran and Pakistan. The review includes all articles published from inception to March 2019. The pooled prevalence for overall PTSD was 55.6% (95% CI: 49.9–61.3). It was 60.2% (95% CI: 54.1–66.3) and 49.2% (95% CI: 39.4–59) for Iranian and Pakistani survivors, respectively. Women experienced higher incidence of PTSD than men. The variation of PTSD based on the clinical interview was lower than the self-report approach. The interval time between the earthquakes and the assessment showed that the prevalence of PTSD decreased over time. The prevalence of PTSD in Iran and Pakistan was higher than the global average, and the rate of the disorder in Iran was higher than in Pakistan. Sex, method of assessment, and time lag between the occurrence of disaster and assessment of PTSD affect the prevalence.

Toward Reduced Burden in Evidence-Based Assessment of PTSD: A Machine Learning Study

Structured diagnostic interviews involve significant respondent burden and clinician administration time. This study examined whether we can maintain diagnostic accuracy using fewer posttraumatic stress disorder (PTSD) assessment questions. Our study included 1,265 U.S. veterans of the Afghanistan and Iraq conflicts who were assessed for PTSD using the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (SCID-5). We used random forests to assess the importance of each diagnostic item in predicting a SCID-5 PTSD diagnosis. We used variable importance to rank each item and removed the lowest ranking items while maintaining ≥90% accuracy (i.e., efficiency), sensitivity, and other metrics. We eliminated six diagnostic items among the overall sample, four items among male veterans, and six items among female veterans. Our findings demonstrate that we may shorten the SCID-5 PTSD module while maintaining excellent diagnostic performance. These findings have implications for potentially reducing patient and provider burden of PTSD diagnostic assessment.