Evaluation of an adapted version of the International Trauma Questionnaire for use by people with intellectual disabilities

Peter E. Langdon, Jonathan I. Bisson, Gemma Rogers, Sophie Swain, Steve Hiles, Alan Watkins, Paul Willner

Research output: Contribution to journalArticlepeer-review


Aims: The International Trauma Questionnaire (ITQ) is a novel assessment instrument that is aligned to the ICD-11 diagnoses of post-traumatic stress disorder (PTSD) and complex PTSD (CPTSD). The purpose of this study was to develop and evaluate an adapted version of the ITQ suitable for use by people with intellectual disabilities. Methods: The ITQ-ID follows the original ITQ, using wording developed in collaboration with a focus group of people with intellectual disabilities The ITQ-ID was administered to 40 people with intellectual disabilities recruited from learning disability forensic and community settings, alongside a Trauma Information Form and the Impact of Event Scale-Intellectual Disabilities (IES-IDs). Results: Most participants reported multiple traumatizing events. Around half of the participants met strict criteria for a diagnosis of PTSD, and around three quarters met looser criteria. Depending on definitions, between 66% and 93% of those who met criteria for PTSD also met criteria for a diagnosis of CPTSD. The ITQ-ID showed a single-component structure, with very good-to-excellent internal consistency, excellent test–retest reliability, and evidence of concurrent, discriminant, and content validity. Significance: The results support the potential of the ITQ-ID for assessment of PTSD and CPTSD in people with intellectual disabilities in both clinical and research contexts and highlight the need for further validation work.

Original languageEnglish
Pages (from-to)471-482
Number of pages12
JournalBritish Journal of Clinical Psychology
Issue number2
Early online date17 Mar 2023
Publication statusPublished - Jun 2023
Externally publishedYes


  • intellectual disability
  • International Trauma Questionnaire
  • PTSD

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