title: Towards the validation of the international trauma interview for post-traumatic stress disorder and complex post-traumatic stress disorder, and the role of core beliefs in the development and maintenance of CPTSD
Creators: name: Wagland, Zoe
Publisher: name: Edinburgh Napier University
publisherIdentifier: https://ror.org/03zjvnn91
publisherIdentifierScheme: ROR
Year: 2024

description: Background
Complex post-traumatic stress disorder (CPTSD) was added to the International Classification of Diseases 11th edition (ICD-11) as a sibling diagnosis to post-traumatic stress disorder (PTSD) (WHO, 2018). To date the only validated measure for CPTSD is the International Trauma Questionnaire (ITQ) (Redican et al., 2021). However, the current gold standard for diagnosis is a clinician interview (Siqveland et al., 2017). For the reliable diagnosis of CPTSD, it is important that a diagnostic interview protocol be developed. The International Trauma Interview (ITI) (Roberts et al., 2019), is based on the ITQ and intends to fill the need for an interview CPTSD measure, however validation is necessary.
This thesis is also concerned with the relationship between CPTSD and negative core beliefs (NCBs). An NCB is defined as a core belief or schema detailing negative beliefs about the self. This relationship may help to shed light on how CPTSD is developed and maintained, and how CPTSD may be treated. Research already shows how PTSD relates to NCBs, and this has informed the successful use of cognitive behavioural therapies for PTSD.
Research questions
1)
What research already exists about the correlation between CPTSD and NCBs?
2)
What NCBs are correlated with CPTSD when CPTSD is measured with the ITQ?
3)
Is the ITI a reliable and valid assessment tool for CPTSD?
Methods
A meta-analysis was conducted to collate data published in pre-existing studies that explore associations between DSO symptoms and NCBs, with the view to understand what is already known, and identify gaps in the literature. The search strategy identified studies measuring the relationship between NCBs and proxy measures of DSO symptoms. R values were extracted and analysed in a random effects meta-analysis.
In order to address gaps in the literature and establish the relationship between NCBs and a direct measure of PTSD/CPTSD, an online survey (n=2,144) was also conducted to collect empirical data based on the findings from the meta-analysis. A measure of NCBs (core beliefs questionnaire, Wong et al., 2017) is administered alongside the ITQ. Correlational and reliability analyses were run.
Finally, this thesis aimed to provide a provisional validation of the ITI for assessment of PTSD and CPTSD. Participants (n=25) were recruited from NHS psychology services and administered both the ITQ and the ITI. These data were analysed for validity and reliability. Concurrent validity was measured by the agreement between the ITI and ITQ using Pearson’s r, internal reliability was analysed with Cronbach’s Alpha, and clinical utility was analysed qualitatively.
Results
The results of the meta-analysis suggest moderate positive correlations between CPTSD symptoms and NCBs. Further research using direct measures of CPTSD symptoms and using clinical populations was recommended.
The results of the large-sample study show very strong correlations between NCBs and PTSD/CPTSD symptom profiles. Some types of NCBs are strongly associated with CPTSD, NCBs are less significantly correlated with NCBs. Steps must be taken to replicate these findings with clinical populations to draw conclusions for therapeutic practice.
The ITI showed promise as a CPTSD assessment tool but the sample in this thesis was too small to be counted as a standalone validation study. Further research is required to establish the validity and reliability of the English language version of the ITI.
Discussion
The meta-analysis indicated positive, moderate correlations between NCBs and proxy measures of DSO symptoms. Gaps in the literature are identified as weaknesses in reporting of data by published studies. Many studies omitted demographic data, power analyses, and the use of proxy measures causes issues with validity of results.
The large-sample online survey study revealed strong correlations between specific NCBs and CPTSD symptom profiles, and the negative self-concept DSO symptoms were the most strongly correlated. There was no significant difference in endorsement of NCBs between participants with PTSD and non-symptomatic profiles. CPTSD symptom profiles correlated significantly more strongly with NCBs than either PTSD or non-symptomatic profiles. This indicates that there is a significant difference between the cognitive structure of CPTSD and PTSD/non-symptomatic profiles.