As simple as possible, but not simpler: Revisiting the International Trauma Questionnaire (ITQ) complex PTSD items omitted in the shortened version

Background: The risks of oversimplification of the symptomatology of Complex PTSD (CPTSD) have been highlighted in the literature.

Objective: To re-examine 10 items representing disturbances in self-organization (DSO) that were deleted from the original 28-item version of the International Trauma Questionnaire (ITQ) when creating the current 12-item version.

Participants and setting: An online convenience sample of 1235 MTurk users.

Methods: Online survey comprising the fuller 28-item previous version of the ITQ, Adverse Childhood Experiences (ACEs) questionnaire, and PTSD Checklist for DSM-5 (PCL-5).

Results: First, averaged endorsement of the 10 omitted items was lower than the 6 retained DSO items (d' = 0.34). Second, the 10 omitted DSO items accounted for incremental variance over and correlated equivalently to the 6 retained items with the PCL-5. Third, only the 10 omitted DSO items (r_-part = 0.12) while not the 6 retained DSO items (r_-part = -0.01) independently predicted ACE scores and, eight of these ten omitted DSO items differentiated higher ACE scores even among the subset of 266 participants who endorsed all 6 of the retained DSO items, most with medium effect sizes. Fourth, exploratory principal axis factor analysis differentiated two latent variables within the fuller set of 16 DSO symptoms, with the strongest indicators of the second factor, namely uncontrollable anger, recklessness, derealization, and depersonalization, being unmeasured within the 6 retained DSO items. Moreover, scores on both factors independently predicted both PCL-5 and ACE scores.

Conclusions: There are conceptual and pragmatic advantages to revisiting a more content-valid and comprehensive conceptualization of CPTSD and DSO, partially as may be measured by the recently deleted items from the original and fuller length ITQ.