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Understanding complex trauma

The major aims of the Trauma and Complex Mental Health Problems Research Unit are to improve our understanding and measurement of post-traumatic stress disorder and complex post-traumatic stress disorder. Much of our research involves collaboration with a range of influential international researchers, and our findings are having a major impact on current conceptualisations of trauma and its psychological aftermath. Details of the projects we have been involved in are outlined below.

Shevlin, Hyland, Brewin, Cloitre, Bradley, Kitchiner... Roberts (in press)


  • We set out to investigate the association between negative trauma-related cognitions, emotional regulation strategies, and attachment style and Complex Posttraumatic Stress Disorder (CPTSD).

  • Measures of CPTSD, negative trauma-related cognitions, emotion regulation strategies, and attachment style were completed by a British clinical sample of trauma-exposed patients (N = 171)

  • It was found that the most important factor in the diagnosis of CPTSD was negative trauma-related cognitions about the self, followed by attachment anxiety, and expressive suppression, suggesting targeting negative thoughts and attachment representations while promoting skills acquisition in emotional regulation hold promise in the treatment of CPTSD.

Ben-Ezra, Karatzias, Hyland, Brewin, Cloitre, Bisson, …Shevlin (in press).

  • The current study sought to advance the existing literature by providing the first assessment of the factorial and discriminant validity of the ICD-11 proposals for PTSD and CPTSD in a nation-wide level.

  • A nationally representative sample from Israel (n = 1003) using a disorder-specific measure (ITQ; International Trauma Questionnaire) in order to assess PTSD and Complex PTSD along with the Life Events Checklist and the World Health Organization Well-Being Index.

  • Estimated prevalence rates of PTSD and CPTSD were 9.0% and 2.6% respectively.

  • The structural analyses indicated that PTSD and disturbances in self-organization symptom clusters were multidimensional, but not necessarily hierarchical, in nature and there were distinct classes that were consistent with PTSD and CPTSD.

  • These results partially support the factorial validity and strongly support the discriminant validity of the ICD-11 proposals for PTSD and CPTSD in a nationally representative sample using a disorder-specific measure, findings also supported the international applicability of these diagnoses.

Hyland, Shevlin, Fyvie & Karatzias (in press)

  • The objectives of this study were to (1) compare prevalence rates based on different diagnostic system, (2) identify clinical and behavioural variables that distinguish ICD-11 CPTSD and PTSD diagnoses, and (3) examine the diagnostic associations for ICD-11 CPTSD and DSM-5 PTSD.

  • A predominately female, clinical sample (N = 106) completed self-report scales to measure ICD-11 PTSD and CPTSD, DSM-5 PTSD, depression, anxiety, borderline personality disorder, dissociation, destructive behaviours, and suicidal ideation and self-harm. Significantly more people were diagnosed with PTSD according to the DSM-5 criteria compared to those diagnosed with PTSD and CPTSD according to the ICD-11 guidelines (90.4% vs 79.8%).

  • An ICD-11 CPTSD diagnosis was distinguished from an ICD-11 PTSD diagnosis by higher levels of dissociation (d = 1.01), depression (d = .63), and borderline personality (d = .55). Diagnostic associations with depression (by 10.7%), anxiety (by 4.0%) and suicidal ideation and self-harm (by 7.0%) were higher for ICD-11 CPTSD compared to DSM-5 PTSD.

  • These results have implications for differential diagnosis and for the development of targeted treatments for CPTSD.


Hyland, Shevlin, Brewin, Cloitre, Downes, Jumbe... Roberts (2017)

  • Using a newly developed, disorder-specific measure of PTSD and CPTSD called the International Trauma Questionnaire (ITQ) this study (1) assessed the factorial validity of ICD-11 PTSD and CPTSD; (2) provided the first test of the discriminant validity of these constructs; and (3) provided the first comparison of ICD-11, and Diagnostic and Statistical Manual, Fifth Edition (DSM-5), PTSD diagnostic rates using disorder-specific measures.

  • ICD-11 and DSM-5 PTSD specific measures were completed by a British clinical sample of trauma-exposed patients (N = 171). The structure and validity of ICD-11 PTSD and CPTSD were assessed by means of factor analysis and assessing relationships with criterion variables.

  • Diagnostic rates under ICD-11 were significantly lower than those under DSM-5. A two-factor second-order model reflecting the distinction between PTSD and CPTSD best represented the data from the ITQ; and the PTSD and CPTSD factors differentially predicted multiple psychological variables.

  • The factorial and discriminant validity of ICD-11 PTSD and CPTSD was supported, and ICD-11 produces fewer diagnostic cases than DSM-5.

  • The paper is available here.

Karatzias, Power, Woolston, Apurva, Begley, Quinn... Purdie (2017)

  • We hypothesised that the experience of trauma in adulthood, post-traumatic stress disorder (PTSD) and emotional dysregulation would mediate the relationship between childhood traumatic events and later criminal behaviour.

  • Almost all (91%) of 89 female offenders reported both childhood and adulthood trauma. Over half (58%) met the criteria for DSM-5 PTSD. Multiple traumas were significantly associated with seriousness of offence, as indicated by sentence length.

  • Adult experience of trauma was the only significant mediator between childhood trauma and subsequent offending.

  • Women who have experienced multiple traumatic events may be more likely to commit serious offences, so it is very important to assess and meet their trauma-related needs.

  • The paper is available here.

Shevlin, Hyland, Karatzias, Bisson & Roberts (2017)

  • In this study, we derived prevalence rates based on commonly reported models of PTSD, based on data from two clinical samples (N = 434), and also assessed if the different models generated consistent risk estimates in relation to the effects of childhood maltreatment.

  • We found that the different models produced different prevalence rates, ranging from 64.5% to 83.9%.

  • We also found that the relationship between childhood maltreatment and ‘diagnosis’ varied considerably depending upon which latent symptom profile was adopted.

  • The paper is available here.


Shevlin, Hyland, Karatzias, Fyvie, Roberts, Bisson …Cloitre (2017)

  • Participants in this cross-sectional study were a sample of individuals who were referred for psychological therapy to a National Health Service (NHS) trauma centre in Scotland (N=195).

  • The results indicate that a structural model incorporating six first-order factors (re-experiencing, avoidance of traumatic reminders, sense of threat, affective dysregulation, negative self-concept, and disturbances in relationships) and two second order factors (PTSD and Disturbances in Self-Organization [DSO]) was the best fitting.

  • The model presented with good concurrent validity.

  • Childhood trauma was found to be more strongly associated with DSO than PTSD.

  • These results are in support of the ICD-11 proposals for PTSD and CPTSD.

  • The paper is available here.

Yan & Karatzias (2016)

  • This study examined the associations between life adversities and intimate partner violence using a representative sample of 1,239 men and women aged between 18 and 97.

  • Results show that intimate partner violence is common with 32.8% of the participants having reported past year psychological aggression, 4.5% reported physical abuse, and 1.1% reported injury.

  • Various life adversities were also common with 21.7% having reported family disruption, 6% having experienced abuse or witnessing violence, and 2.1% life-threatening events.

  • Logistic regression analyses revealed that experiencing abuse or witnessing violence in childhood is associated with a greater risk of past year psychological aggression, physical assault, and injury.

  • Altogether, our results point out that childhood victimization, especially physical abuse by parents, is associated with future long-term risk of IPV. This highlights the importance of early prevention and intervention for child abuse.

  • The paper is available here.

Howard, Karatzias, Power & Mahoney (2017)

  • The current study explored pathways to self-harm following childhood trauma, by investigating the mediating roles of Post-traumatic Stress Disorder (PTSD) symptoms, emotion regulation and dissociation, in this relationship, within a sample of 89 female prisoners.

  • The majority of the sample (58.4%) reported a history of self-harm. Bootstrapped mediation analyses indicated an indirect effect of emotion regulation on the relationship between childhood trauma and self-harm. An indirect effect was also found for PTSD arousal/reactivity cluster of symptoms. Multiple mediation analyses revealed that interactional effects were present for emotion regulation and arousal/reactivity, and emotion regulation and dissociation, respectively.

  • Self-harm is highly prevalent among female prisoners. Interventions promoting emotion regulation and addressing arousal/reactivity symptoms following traumatization may provide an effective way of addressing this problem.

  • The paper is available here.

Karatzias, Howard, Power, Socherel, Heath & Livingstone (2016)

  • In the present study, we set out to compare people with functional neurological disorders, and organic neurological disorders, in terms of childhood and adulthood traumatic events, traumatic stress, emotional dysregulation and symptoms of depression and anxiety.

  • Sample consisted of a consecutive series of people with functional neurological disorders and with organic neurological disorders (n = 82) recruited from a hospital in Scotland.

  • The two groups were found to significantly differ in relation to all measures, with the MUS group being more likely to report childhood and adulthood life events, more severe emotional dysregulation, traumatic stress and symptoms of anxiety and stress.

  • Our results suggest that identifying and addressing the impact of childhood trauma, may alleviate distress and aid recovery from functional neurological disorders.

  • The results are available here.

Karatzias, Jowett, Yan, Raeside & Howard (2016)

  • We set out to investigate the mediating roles of depression, resilience, smoking, and alcohol use, in the relationship between potentially traumatic life events and objective and subjective, physical and mental health in a single study.

  • A face-to-face, population-based survey was conducted in Hong Kong (N = 1147).

  • Our results indicate that psychological factors rather than biological are important mediators of the relationship between life events exposure and health.

  • Our findings provide evidence that depressive symptomatology has a mediating role only in the case of specific potentially traumatic life events and that resilience is only a critical factor in the face of exposure to multiple traumatic events, rather than single events.

  • Our results also indicate that behavioural factors, such as smoking and drinking, are not significant mediators of the relationship between life events and health.

  • The paper is available here.

Howard, Karatzias, Power & Mahoney (2017)

  • A cross-sectional, interview-format questionnaire study was undertaken with a sample of 89 female prisoners.

  • History of drug use was significantly correlated with trauma, PTSD status, and violent offending. A mediation analysis identified an indirect effect of PTSD symptoms on the relationship between history of drug use and violent offending.

  • These findings highlight the importance of addressing PTSD symptoms and substance misuse, among female offenders, to help prevent violent offending.

  • The paper is available here.

Karatzias, Cloitre, Brewin, Bisson, Roberts, Wilson... Shevlin (2016)

  • The primary aim of this study was to provide an assessment of the reliability and validity of a newly developed self-report measure of ICD-11 PTSD and CPTSD: the ICD-11 Trauma Questionnaire (ICD-TQ).

  • Participants in this study were a sample of individuals who were referred for psychological therapy to a National Health Service (NHS) trauma centre in Scotland (N = 193).

  • The results provide initial support for the psychometric properties of this initial version of the ICD-TQ

  • The paper is available here.

Karatzias, Shevlin, Fyvie, Hyland, Efthymiadou, Wilson... Cloitre (2016)

  • We set out to explore whether the newly developed ICD-11 Trauma Questionnaire (ICD-TQ) can distinguish between classes of individuals according to the PTSD and CPTSD symptom profiles as per ICD-11 proposals based on latent class analysis.

  • Overall, results indicate that using the newly developed ICD-TQ, two subgroups of treatment-seeking individuals could be empirically distinguished based on different patterns of symptom endorsement; a small group high in PTSD symptoms only and a larger group high in CPTSD symptoms.

  • In addition, CPTSD was more strongly associated with more frequent and a greater accumulation of different types of childhood traumatic experiences and poorer functional impairment.

  • CPTSD is highly prevalent in treatment seeking populations who have been multiply traumatised in childhood and adulthood and appropriate interventions should now be developed to aid recovery from this debilitating condition.

  • The paper is available here.

Karatzias, Jowett, Begley & Deas (2016)

  • We set out to investigate the association between EMS and common forms of psychopathology in a sample of women with a history of interpersonal trauma (n=82). We have hypothesised that survivors of interpersonal trauma will present with elevated EMS scores compared to a non-clinical control group (n=78). We have also hypothesised that unique schemas will be associated with unique psychopathological entities and that subgroups of interpersonal trauma survivors would be present in our sample, with subgroups displaying different profiles of schema severity elevations.

  • It was found that survivors of interpersonal trauma displayed elevated EMS scores across all 15 schemas compared to controls. Although the pattern of associations between different psychopathological features and schemas appears to be rather complex, schemas in the domains of Disconnection and Impaired Autonomy formed significant associations with all psychopathological features in this study.

  • Our findings support the usefulness of cognitive behavioural interventions that target schemas in the domains of Disconnection and Impaired Autonomy in an effort to modify existing core beliefs and decrease subsequent symptomatology in adult survivors of interpersonal trauma

  • The paper is available here.

Karatzias, Yan, & Jowett (2015)

  • This was a cross-sectional, face-to-face household population based survey of adults (18+) in Hong Kong (N=1,147).

  • Overall, results indicate that specific adverse life events may be associated with specific health conditions. However, all tested life events were associated with subjective physical and mental health. Death of partner or parent and life threatening illness or injury were found to have the strongest association with physical health problems. A dose-response relationship between adverse life events and physical health in general was evident but more so for heart disease and eyesight degeneration.

  • Considering the high prevalence of traumatic events and how common the conditions associated with such events are in the general population, screening for adverse life events as part of comprehensive assessment will allow a deeper understanding of patients’ needs.

  • The paper is available here.

Krzeczkowska, Karatzias, & Dickson (2014)

  • This exploratory study investigated the extent to which severity of pain was related to coping strategies and post-traumatic symptomatology in people with CFS/ME.

  • Participants comprised 27 individuals with CFS/ME and 27 healthy controls.

  • It was found that CFS/ME participants present with significantly more post-traumatic stress symptoms and report significantly less emotion focused strategies and problem focused coping strategies compared with healthy controls.

  • Severity of pain in the CFS/ME subgroup was not associated with traumatic symptomatology, although those with severe pain reported less use of self-distraction, positive re-framing and acceptance than those with mild pain.

  • Our results suggest that the enhancement of certain coping strategies (facilitated by psychological interventions such as acceptance and commitment therapy) may be beneficial in alleviating pain in people with CFS/ME.

  • The paper is available here.

Bak-Klimek, Karatzias, Campbell, Pugh, Laybourn, Elliott (2014).

  • This is the first study which investigates the relationship between a wide range of sexual abuse characteristics (i.e. age at onset, frequency of assaults, number of perpetrators and their relationship to the victim) and the severity of psychopathological disorders in a large sample of adult child sexual abuse (CSA) survivors who attended a specialist Psychotherapy Service for CSA survivors.

  • CSA survivors in our study experienced severe sexual assault(s) in their early years and presented with severe pathology which could suggest a strong causal link.

  • However, none of the examined trauma characteristics significantly predicted severity of psychopathology.

  • The study adds to the growing body of evidence suggesting that CSA effects may be dependent on factors which are not necessarily related to the nature of sexual abuse.

  • The paper is available here.

Coyle, Karatzias, Summers & Power (2013)

  • This paper examines the relationships between type of emotions experienced, emotion regulation strategies, and psychological trauma symptoms in a sample of survivors of CSA.

  • A consecutive case series of CSA survivors (n=109) completed the Basic Emotions Scale (BES)-Weekly, General, and Coping versions; the Regulation of Emotions Questionnaire; the Post-traumatic Stress Checklist-Civilian Version (PCL-C); and the Clinical Outcomes in Routine Evaluation Outcome Measure. RESULTS:

  • Significantly higher levels of disgust than other levels of emotions were reported on the weekly version of the BES.

  • In addition, significantly higher levels of disgust and lower levels of happiness were reported on the BES-General subscale.

  • The findings highlight the utility of profiling basic emotions in understanding the strong associations between emotional phenomena, particularly the emotion of disgust and psychopathology in CSA survivors.

  • The paper is available here.

Chouliara, Karatzias, & Gullone (2012)

  • This study elicited experiences of recovery from CSA in male and female survivors who have/have not utilized mental health services. The tangible end-point was to propose a theoretical model of personally meaningful recovery.

  • This is a qualitative study, which utilized semi-structured individual interviews following the critical incident technique.

  • Main themes identified were: The Affected Self, Factors Hindering Recovery, Factors Enhancing Recovery, The Hurdles of Recovery and the Recovering Self. The affected self included: lack of boundary awareness and self-blame, over self-reliance, over-vigilance and guilt, shame, aloneness and social stigma. The recovering self was characterized by increasing confidence, assertiveness, ability to self-care and self-acceptance, and by embracing vulnerability.

  • The importance of disclosure in the healing process seemed paramount and can have major implications for current service protocols.

  • The paper is available here.

Karatzias, Chouliara, Power, Brown, Begum, McGoldrick & MacLean (2012).

  • We set out to investigate levels of life satisfaction and its demographic, trauma related and clinical predictors in a sample of people with PTSD (n  =  46).

  • Our results indicated that people with moderately severe PTSD in the community are likely to experience lower levels of life satisfaction compared with those with other psychiatric conditions or those without any diagnoses. Multivariate analysis revealed that marital status and trauma symptoms were the only significant predictors of life satisfaction.

  • The strong association between traumatic symptomatology and life satisfaction may indicate that routine assessment for life satisfaction or similar positive constructs in people with PTSD, referred for psychological therapies might be useful.

  • The paper is available here.

Chouliara, Karatzias, Scott-Brien, Macdonald, MacArthur & Frazer (2011)

  • This review summarises and evaluates evidence regarding psychotherapy/counselling services for childhood sexual abuse (CSA) from the survivors' perspective.

  • Nine studies met the inclusion criteria for this review. Survivors identified a range of experiences of services. Positive experiences focused mainly on the therapeutic relationship, and the importance of awareness about issues specific to survivors. Negative experiences included taking a sexual interest in clients, dealing ineffectively with errors, being unresponsive, and prescription of heavy medications.

  • Future research should obtain survivors' perspectives across genders, sexual orientation and ethnic background, and focus more on survivors' negative experiences.

  • The paper is available here.

Karatzias, Power, Brown & McGoldrick (2009)

  • The present study aimed to investigate correlates of dissociation in outpatients with chronic PTSD in Scotland.

  • A total of 102 participants completed the Dissociative Experiences Scale, the Positive and Negative Affect Schedule, and the Clinician-Administered PTSD Scale. Information regarding trauma characteristics (i.e., type and presence of physical injury) was also collected.

  • Regression analysis revealed that increased severity and frequency of posttraumatic symptoms, as measured by the Clinician-Administered PTSD Scale total, was the only significant predictor of dissociation.

  • Our findings indicate that chronic PTSD symptoms could be contributing

  • to the maintenance of clinical dissociation and vice versa in this sample of Scottish outpatients.

  • The paper is available here.

Karatzias, Power, Brown & McGoldrick (2009)

  • The present study aimed to investigate demographics, trauma variables, PTSD symptomatology, co-morbid psychopathology, dissociation and personality variables as correlates of vividness of imagery (i.e. general ability to imagine objects) in people with PTSD.

  • Participants were 98 outpatients with PTSD who completed a number of self- and assessor-rated measures.

  • Regression analysis showed that the only statistically significant predictor of mental imagery was depression.

  • The paper is available here.

Karatzias & Chouliara (2009)

  • In this paper we attempted to synthesise existing literature on the role of cognitive and emotional appraisals in explaining ill health (i.e. medically explained symptoms), following PTSD.

  • We introduced a conceptualisation aiming to explain poor physical health following PTSD. We proposed that PTSD symptoms will lead to the production of two types of cognitive appraisals: Appraisals about the body that occurred during traumatisation, and cognitive appraisals about PTSD symptoms themselves.

  • Both these cognitive appraisals coupled with negative emotional responses will lead to physiological arousal and negative health behaviours and subsequently to poor health.

  • This conceptualisation has clinical implications for the management of physical health following PTSD.

  • The paper is available here.

In parallel to our efforts to improve our understanding of PTSD and C-PTSD, we are also developing and evaluating psychological interventions for these conditions.

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