Scale Analysis

The International Trauma Questionnaire (ITQ) is a brief, simply worded self-report measure that focuses on the core features of Post-Traumatic Stress Disorder (PTSD) and Complex PTSD (CPTSD). It was published in 2008 by Cloitre and colleagues. The ITQ is consistent with the organizational principles of the International Classification of Diseases (ICD-11), the global standard for health information classification and causes of death, as defined by the World Health Organization.

Purpose

The ITQ is designed to reflect two primary constructs—PTSD and Disturbances in Self-Organization (DSO)—in order to maximize clinical utility and international applicability by focusing on a limited but central set of symptoms.

Item Calibration

There are two versions of this scale: a full version with 22 items and a short form consisting of 12 items. The ITQ items are assessed using a 5-point Likert scale ranging from 0 (Not at all) to 4 (Extremely). Respondents are asked to indicate how much each of the core symptoms has bothered them in the past month, based on their most traumatic experience.

Statistical Analysis

The ITQ-18 yields an overall score by summing the ratings of each item. Based on analyses, it can be concluded that the optimized ITQ performs equally well for clinical and community populations, as there is no evidence of differential item functioning.

Validity and Reliability

Internal consistency was estimated using Cronbach’s alpha (α), which was > 0.77 for all PTSD and DSO subcategories, with the exception of avoidance items, which were slightly below the desired threshold (α = 0.67). Reliability for all PTSD and DSO subcategories was satisfactory, with all Cronbach’s alpha values > 0.79 (Cloitre et al., 2018).

References

Authors: Cloitre M, Shevlin M, Brewin CR, Bisson JI, Roberts NP, Maercker A, Karatzias T, Hyland P.

Keywords

International Trauma Questionnaire, ITQ, PTSD, CPTSD, ICD-11, DSO