Psychometric properties of the Global Psychotrauma Screen in the United States

Background:
Prior research assessing the psychometric properties of the Global Psychotrauma Screen provided support for its internal consistency reliability, construct validity, convergent validity, and divergent validity in several international samples, but not specifically in a U.S. subsample.

Objective:
The purpose of this study was to assess psychometric properties of the GPS in the U.S.

Method:
This observational study included a convenience sample of individually recruited participants (N = 231) who completed an initial study with 126-item online questionnaire and a two-week follow-up study with GPS alone through the weblinks provided by the research team. Data analyzes included measuring internal consistency and test–retest reliability, exploratory and confirmatory factor analyzes (EFA and CFA), convergent and divergent validity, sensitivity, specificity, and severity of the GPS symptom items. Additional CFA was conducted with data (N = 947) from the GPS multinational research project, U.S. subsample.

Results:
The results showed acceptable internal consistency and test–retest reliability, convergent validity, and divergent validity of the GPS. The construct validity results supported a three-factor structure of the GPS symptoms. The GPS domains showed acceptable sensitivity and specificity with the cut-off scores of 3 for PTSD and 5 for CPTSD domains; and the scores of 1 for the anxiety, depression, and insomnia domains respectively. The GPS risk factors predicted the GPS symptom severity.

Conclusions:
This study provides new and additional evidence on the psychometric properties of the GPS which may help health care providers with the selection of an appropriate screening instrument for trauma-related transdiagnostic symptoms. The study limitations should be addressed in future research through the replication of EFA and CFA internationally with larger samples, and the inclusion of a reference standard for dissociation.