Global Psychotrauma Screen (GPS): psychometric properties in two Internet-based studies

Area of Science:

• Psychology
• Psychiatry
• Trauma Studies

Background:

• Potentially traumatic stressors can lead to various transdiagnostic outcomes beyond Posttraumatic Stress Disorder (PTSD).
• Currently, no brief screening tools exist for measuring posttraumatic responses in a transdiagnostic manner.
• This gap highlights the need for a comprehensive screening instrument.

Purpose of the Study:

• To assess the psychometric characteristics of the Global Psychotrauma Screen (GPS), a new 22-item transdiagnostic screening measure.
• To evaluate the validity and reliability of the GPS for identifying a range of posttraumatic outcomes.
• To explore the factor structure and group differences in responses to the GPS.

Main Methods:

• An internet survey was administered to a large sample (N=2,646) recruited via the Global Collaboration on Traumatic Stress (GC-TS) website and Amazon's MTurk.
• Methods included exploratory factor analysis, correlational analysis, and sensitivity/specificity analysis.
• Comparisons were made between samples and between male and female respondents.

Main Results:

• Exploratory factor analysis revealed a single factor underlying symptom endorsements, suggesting a unitary transdiagnostic posttraumatic outcome.
• Convergent validity was established with measures of PTSD and dissociative symptoms.
• A GPS symptom cut-off score of 8 demonstrated optimized sensitivity and specificity for probable PTSD.

Conclusions:

• The Global Psychotrauma Screen (GPS) shows preliminary support for its validity as a screener for concurrent measurement of transdiagnostic outcomes of potentially traumatic stressors.
• The apparent unifactorial structure suggests a single, unitary posttraumatic outcome.
• Future research should evaluate the GPS's psychometric properties in other languages.