The International Trauma Questionnaire (ITQ) is an 18-item self-report measure designed to assess symptoms of Post Traumatic Stress Disorder (PTSD) and Disturbances in Self Organization (DSO), which together constitute Complex PTSD (CPTSD) in accordance with the International Classification of Diseases 11 (ICD-11) conceptualisation of trauma-related diagnoses.
The International Trauma Questionnaire (ITQ) is based on the International Classification of Diseases 11 (ICD-11) model of trauma-related diagnoses, offering a clinically relevant tool for identifying PTSD and Complex PTSD (CPTSD) symptoms.
Example ITQ Items
The ITQ has two subscales with three symptom clusters in each.
Post Traumatic Stress Disorder (PTSD)
Disturbances in Self Organization (DSO)
The ITQ reliably discriminates between people with PTSD alone and those with CPTSD. Individuals with PTSD alone score above the threshold on the PTSD symptom clusters without meeting criteria for DSO, whereas those with CPTSD score above the threshold on both PTSD and DSO subscales. The ITQ also assesses functional impairments associated with PTSD and DSO, ensuring a comprehensive assessment of trauma-related symptoms and their impact on functioning.
Scores on the ITQ indicate the presence and severity of PTSD and/or DSO symptoms and associated functional impairments. The ITQ can be used by qualified professionals, such as psychologists, as part of a comprehensive diagnostic assessment process for PTSD and CPTSD and for monitoring treatment progress over time.
Compared to other PTSD assessment tools, such as the PTSD Checklist for DSM-5 (PCL-5), the ITQ has a distinct advantage in its inclusion of CPTSD.
Research suggests that CPTSD is experienced by approximately 40-50% of individuals who meet criteria for a trauma-related disorder (Karatzias et al., 2017). People with CPTSD tend to experience greater functional impairment compared to those with PTSD alone, affecting their relationships, work capabilities, and overall quality of life.
CPTSD is more commonly associated with prolonged, repeated or accumulated interpersonal trauma, such as chronic childhood abuse, neglect or domestic violence (Karatzias et al., 2017).
By differentiating between PTSD and CPTSD, the ITQ helps qualified professionals identify the distinct symptom profiles associated with different trauma experiences. Individuals with CPTSD may benefit from treatment approaches that address not only the core PTSD symptoms but also difficulties with emotional regulation and self-identity. This differentiation allows clinicians to develop more tailored treatment plans based on the specific presentation of trauma-related symptoms.
The International Trauma Questionnaire (ITQ) has two subscales:
It includes six items measuring PTSD symptoms from three symptom clusters:
It also includes six items measuring DSO symptoms from three symptom clusters:
The PTSD and DSO subscales are each accompanied by three items measuring associated functional impairments in the domains of social, occupational, and other important areas of life.
Each item is rated on a 5-point Likert-type scale from 0 to 4.
The scoring approach uses dichotomous scoring for diagnostic purposes and dimensional scoring for symptom severity.
Dichotomous Scoring
A score of 2 (Likert = “Moderately”) or higher on a symptom or functional impairment item indicates the presence (i.e., endorsement) of that symptom or impairment.
PTSD is indicated if:
Complex PTSD (CPTSD) is indicated if:
A person may receive a diagnosis of PTSD or CPTSD, but not both.
Dimensional Scoring
The respondent’s scores are presented as raw scores and as percentiles based on normative data for trauma-exposed adults, contextualising their scores relative to the typical scores of adults in this normative sample. For example, the 50th percentile represents the typical level of symptom severity for an adult who has been exposed to trauma (i.e., “Mild”), while scores on the 90th percentile fall within the top 10% and are considered “Severe”.
Qualitative descriptors categorise the respondent’s scores based on specific ranges of percentiles.
A diagnostic criteria descriptor also accompanies each score, indicating whether diagnostic criteria for PTSD and DSO symptoms are met, and whether specific symptom clusters and functional impairments are present, according to the dichotomous scoring threshold. CPTSD is indicated if the diagnostic criteria descriptor says “Criteria met” for both the PTSD subscale and the DSO subscale.
On first administration, graphs are presented showing the respondent’s scores as percentiles based on normative data for trauma-exposed adults (Baker et al., 2025). A graph is also presented comparing the respondent’s PTSD and DSO symptom severity scores to two samples: (1) the normative sample of trauma-exposed adults; and (2) a diagnostic sample. For the PTSD symptom severity score, this diagnostic sample consists of adults meeting the ITQ’s criteria for PTSD. For DSO symptom severity scores, the diagnostic sample consists of adults meeting the ITQ’s criteria for CPTSD. Shaded areas correspond to scores between the 25th and 75th percentile. This graph contextualises the respondent’s scores relative to typical symptom severity levels in these samples.
If administered more than once, longitudinal graphs are presented for the respondent’s raw PTSD and DSO symptom severity scores, which is useful for monitoring any changes in symptom severity over time and treatment progress and outcomes. A meaningful change in PTSD symptom severity is defined as a change of 6 or more points in the PTSD symptom severity score, and a meaningful change in DSO symptom severity is defined as a change of 7 or more points in the DSO symptom severity score, based on Reliable Change Index (RCI) calculations (i.e., a 6-7 or more point decrease indicates significant improvement; a 6-7 or more point increase indicates significant deterioration; and less than a 6-7 point change indicates no significant change).
The International Trauma Questionnaire (ITQ) has been extensively validated across diverse populations, demonstrating strong reliability and validity as a measure of ICD-11 Post-Traumatic Stress Disorder (PTSD) and Complex PTSD (CPTSD). It facilitates differential diagnosis between PTSD and CPTSD by capturing both PTSD and Disturbances in Self Organization (DSO) symptoms together with associated functional impairment.
Confirmatory factor analysis (CFA) has consistently supported this two-factor second-order structure (i.e., PTSD and DSO). The latent structure of the ITQ has been replicated across multiple studies, showing excellent model fit for trauma-exposed clinical and community samples (Cloitre et al., 2018; Hyland et al., 2017, 2024).
The ITQ has demonstrated excellent internal reliability. Studies have reported high composite reliability (CR) estimates of 0.96 for the PTSD subscale and 0.97 for the DSO subscale as well as CR estimates ranging from 0.86 to 0.96 for the six symptom clusters (Cloitre et al., 2018; Hyland et al., 2017).
The ITQ demonstrates strong concurrent validity, with PTSD symptom scores correlating highly with other established measures of PTSD, such as the PTSD Checklist for DSM-5 (PCL-5) (Cloitre et al., 2021). The ITQ also shows good convergent validity through associations with related constructs. Furthermore, the PTSD and DSO subscales show distinct patterns of association with external variables:
These findings support the discriminant validity of PTSD and CPTSD symptomatology as measured by the ITQ.
The ITQ has been validated as a sensitive measure of treatment-related changes in symptom severity. Research with clinical populations, including military veterans, has demonstrated that ITQ scores significantly decline following psychological interventions (Cloitre et al., 2021).
Studies have also shown that the ITQ’s psychometric properties remain stable across diverse cultural groups and in multiple languages, reinforcing its validity for use in trauma-exposed populations worldwide (Hyland et al., 2024).
Thus, the ITQ demonstrates strong psychometric properties, including robust reliability, validity, and sensitivity to change, as well as cross-cultural and multilingual applicability. By assessing PTSD and DSO symptoms together with associated functional impairment, it has become the most widely used tool for the assessment and differential diagnosis of PTSD and CPTSD in clinical settings (Sarr et al., 2024).
Percentiles for normative and diagnostic samples, developed by NovoPsych, are presented in NovoPsych’s review of the ITQ (Baker et al., 2025), which includes detailed information about the composition of these reference samples.
The ITQ uses two different scoring approaches:
Someone may experience high overall symptom severity (resulting in “Severe” or “Very Severe” descriptors) whilst not meeting the specific pattern required for diagnosis. For a PTSD diagnosis, at least one symptom rated ≥2 (“Moderately” or higher) must be present from EACH of the three PTSD symptom clusters (Re-experiencing, Avoidance, and Sense of Threat), plus functional impairment. For Complex PTSD, the same PTSD criteria must be met PLUS at least one symptom rated ≥2 from EACH of the three DSO symptom clusters (Affective Dysregulation, Negative Self-Concept, and Disturbances in Relationships), with associated functional impairment. If symptoms are concentrated in only some clusters rather than distributed across all required areas, diagnostic criteria won’t be met despite high severity scores.
The ITQ instructions ask respondents to identify “the experience that troubles you most” and answer all questions in relation to that specific traumatic event. This approach ensures consistency throughout the assessment and allows for clearer interpretation of symptoms. If someone is struggling to identify which trauma is most troubling, it may be helpful to consider which event most frequently intrudes into their thoughts, causes the most distress when remembered, or has the greatest impact on their current functioning. The identified trauma should be documented for clinical reference and to track any changes if the measure is re-administered.
Complex PTSD includes all the core PTSD symptoms plus additional Disturbances in Self Organisation (DSO) – difficulties with emotional regulation, negative self-concept, and relationship disturbances. Research suggests Complex PTSD typically develops following prolonged or repeated interpersonal trauma, particularly during childhood, whilst PTSD more commonly follows single-incident traumas. This distinction has important treatment implications: whilst both conditions benefit from trauma-focused interventions, Complex PTSD often requires additional therapeutic attention to emotional regulation skills, self-identity work, and relationship patterns. The ITQ helps identify which presentation is present, allowing for more tailored treatment planning.
The ITQ can be administered regularly throughout treatment to track changes in both PTSD and DSO symptoms. Many clinicians administer it monthly or at key treatment milestones, though more frequent administration (fortnightly or weekly) may be appropriate during intensive interventions. There are also alternative assessments that could be better for tracking progress of trauma treatment. For example, the Trauma Recovery Measure (TRM) is a good option where the focus is upon the recovery journey as opposed to a reduction in symptoms.
The standard ITQ is designed for adults aged 18 and over. There is the International Trauma Questionnaire – Child and Adolescent Version (ITQ-CA) that is specifically designed for ages 7 to 17, so this might be a better option for younger people.
Cloitre, M., Shevlin, M., Brewin, C. R., Bisson, J. I., Roberts, N. P., Maercker, A., Karatzias, T., & Hyland, P. (2018). The International Trauma Questionnaire: Development of a self-report measure of ICD-11 PTSD and Complex PTSD. Acta Psychiatrica Scandinavica, 138(6), 536–546. https://doi.org/10.1111/acps.12956
Baker, S., Smyth, C., Bartholomew, E., Buchanan, B., & Hegarty, D. (2025). A Review of the Clinical Utility and Psychometric Properties of the International Trauma Questionnaire (ITQ): Percentile Rankings and Qualitative Descriptors.
Cloitre, M., Hyland, P., Prins, A., & Shevlin, M. (2021). The International Trauma Questionnaire (ITQ) measures reliable and clinically significant treatment-related change in PTSD and Complex PTSD. European Journal of Psychotraumatology, 12(1), 1930961. https://doi.org/10.1080/20008198.2021.1930961
Cloitre, M., Shevlin, M., Brewin, C. R., Bisson, J. I., Roberts, N. P., Maercker, A., Karatzias, T., & Hyland, P. (2018). The International Trauma Questionnaire: Development of a self-report measure of ICD-11 PTSD and Complex PTSD. Acta Psychiatrica Scandinavica, 138(6), 536–546. https://doi.org/10.1111/acps.12956
Hyland, P., Brewin, C. R., Cloitre, M., Karatzias, T., & Shevlin, M. (2024). Responding to concerns related to the measurement of ICD-11 Complex Posttraumatic Stress Disorder using the International Trauma Questionnaire. Child Abuse & Neglect, 147, 106563. https://doi.org/10.1016/j.chiabu.2023.106563
Hyland, P., Shevlin, M., Brewin, C. R., Cloitre, M., Downes, A. J., Jumbe, S., Karatzias, T., Bisson, J. I., & Roberts, N. P. (2017). Validation of Post-Traumatic Stress Disorder (PTSD) and Complex PTSD using the International Trauma Questionnaire. Acta Psychiatrica Scandinavica, 136(3), 313–322. https://doi.org/10.1111/acps.12771
Karatzias, T., Shevlin, M., Fyvie, C., Hyland, P., Efthymiadou, E., Wilson, D., Roberts, N., Bisson, J. I., Brewin, C. R., & Cloitre, M. (2017). Evidence of distinct profiles of Posttraumatic Stress Disorder (PTSD) and Complex Posttraumatic Stress Disorder (CPTSD) based on the new ICD-11 Trauma Questionnaire (ICD-TQ). Journal of Affective Disorders, 207, 181–187. https://doi.org/10.1016/j.jad.2016.09.032
Sarr, R., Quinton, A., Spain, D., & Rumball, F. (2024). A systematic review of the assessment of ICD-11 Complex Post-Traumatic Stress Disorder (CPTSD) in young people and adults. Clinical Psychology & Psychotherapy, 31(3), e3012. https://doi.org/10.1002/cpp.3012
