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The Danish Center of Psychotraumatology

The structure of trauma diagnoses

In a number of different contexts, the Danish Center for Psychotraumatology has studied the trauma structures for PTSD and CPTSD, and validated the diagnostic constructs. Get an overview of our research in the lists below.

For a complete overview of all our PTSD studies, click here.

What is post-traumatic stress disorder (PTSD)?

Post-traumatic stress disorder (PTSD) is a relatively long-term and sometimes persistent condition. PTSD can occur after severe catastrophic psychological stresses. These can include accidents, war, disasters and abuse.
PTSD is characterised by constant reliving (flashbacks) of the frightening event, both when awake and often as nightmares.
You try to avoid situations or things that remind you of the event. This is called avoidance behaviour and will often contribute to exacerbating the condition.
Many suffer from irritability, difficulty sleeping, difficulty concentrating and remembering, and mood swings. Relationships with close family and friends are often affected.


Why do people get PTSD?

All people will react with psychological symptoms to extreme events. It is therefore normal to experience symptoms for days to weeks after a violent experience. This can be flashback experiences, for example.
If you have been involved in a serious road accident, you may very often hear sounds from the accident afterwards: screams or sirens, etc. This is very unpleasant, but will usually go away without any special treatment, especially if you endeavour to live your life as normally as possible and try not to pay attention to the discomfort. However, the event can be so violent or the person affected so vulnerable that actual mental illness - PTSD - develops.
PTSD can be triggered by any event that is perceived as threatening, frightening or horrific, regardless of duration. Sudden events and lack of control over the situation increase the risk. Repeated trauma of the kind mentioned above also increases the risk.



Below you can see a number of published studies on PTSD conducted by the Danish Center for Psychotraumatology.

Post Traumatic Stress Disorder (PTSD)

Elklit, A. (1994). PTSD – en afløser for krisebegrebet? I K.-E. Sabroe et al. (eds.): Psykologi i et jubilæumsperspektivPsykologisk Institut, Aarhus Universitet, 217-243.

The factor structure of DSM-5 posttraumatic stress disorder (PTSD) has been extensively debated with evidence supporting the recently proposed seven-factor Hybrid model. However, despite myriad studies examining PTSD symptom structure few have assessed the diagnostic implications of these proposed models. This study aimed to generate PTSD prevalence estimates derived from the 7 alternative factor models and assess whether pre-established risk factors associated with PTSD (e.g., transportation accidents and sexual victimisation) produce consistent risk estimates.

Seven alternative models were estimated within a confirmatory factor analytic framework using the PTSD Checklist for DSM-5 (PCL-5). Data were analysed from a Malaysian adolescent community sample (n = 481) of which 61.7% were female, with a mean age of 17.03 years.

The results indicated that all models provided satisfactory model fit with statistical superiority for the Externalising Behaviours and seven-factor Hybrid models. The PTSD prevalence estimates varied substantially ranging from 21.8% for the DSM-5 model to 10.0% for the Hybrid model. Estimates of risk associated with PTSD were inconsistent across the alternative models, with substantial variation emerging for sexual victimisation.

These findings have important implications for research and practice and highlight that more research attention is needed to examine the diagnostic implications emerging from the alternative models of PTSD.

Murphy, S., Hansen, M., Elklit, A., Chen, Y.Y., Ghazali, S.R. & Shevlin, M. (2017): Alternative models of DSM-5 PTSD: Examining diagnostic implications. Psychiatric Research, 262, pp. 378-383. Doi: 10.1016/j.psychres.2017.09.011

Alternative symptom profiles for posttraumatic stress disorder (PTSD) are presented in the DSM-5 and ICD-11. This study compared DSM-5 PTSD symptom profiles with ICD-11 PTSD symptom profiles among a large group of trauma-exposed individuals from Denmark. Covariates, and rates of co-occurrence with other psychiatric disorders were also investigated.

A sample of treatment-seeking adult survivors of childhood sexual abuse (n = 434) were assessed using self-report measures of PTSD and other psychiatric disorders. A significantly larger proportion of individuals met caseness for DSM-5 PTSD (60.0%) compared to ICD-11 PTSD (49.1%). This difference was largely attributable to low endorsement of the ICD-11 re-experiencing criteria.

Replacement of the ‘recurrent nightmares’ symptom with the ‘recurrent thoughts/memories’ symptom seemed to balance the proportion of individuals meeting caseness for both taxonomies. Levels of co-occurrence with anxiety and thought disorder were higher for the DSM-5 model of PTSD compared to the ICD-11 model. Current results merit careful consideration in the selection of symptom indicators for the new ICD model of PTSD, particularly with respect to the re-experiencing symptom category.

Hyland, P.; Shevlin, M.; McNally, S.; Murphy, J.; Hansen, M. & Elklit, A. (2016). Exploring differences between the ICD-11 and DSM-5 models of PTSD: Does it matter which model is used? Journal of Anxiety Disorders 37, 48-55. Doi: 10.1016/j.janxdis.2015.11.002

Posttraumatic stress disorder's (PTSD) latent structure has been widely debated. To date, two four-factor models (Numbing and Dysphoria) have received the majority of factor analytic support. Recently, Elhai et al. (2011) proposed and supported a revised (five-factor) Dysphoric Arousal model.

Data were gathered from two separate samples; War veterans and Primary Care medical patients. The three models were compared and the resultant factors of the Dysphoric Arousal model were validated against external constructs of depression and anxiety.

The Dysphoric Arousal model provided significantly better fit than the Numbing and Dysphoria models across both samples. When differentiating between factors, the current results support the idea that Dysphoric Arousal can be differentiated from Anxious Arousal but not from Emotional Numbing when correlated with depression. In conclusion, the Dysphoria model may be a more parsimonious representation of PTSD's latent structure in these trauma populations despite superior fit of the Dysphoric Arousal model.

Armour, C., Elhai, J. D., Richardson, D., Ractliffe, K., Wang, L., & Elklit, A.: Assessing a Five Factor Model of PTSD: Is Dysphoric Arousal a Unique PTSD Construct showing Differential Relationships with Anxiety and Depression? Journal of Anxiety Disorders, 26, 368-376, 2012. Doi: 10.1016/j.janxdis.2011.12.002

The factor structure of posttraumatic stress disorder (PTSD) has been extensively studied in Western countries. Some studies have assessed its factor structure in Asia (China, Sri Lanka, and Malaysia), but few have directly assessed the factor structure of PTSD in an Indian adult sample. Furthermore, in a largely patriarchal society in India with strong gender roles, it becomes imperative to assess the association between the factors of PTSD and gender.

Objective:The purpose of the present study was to assess the factor structure of PTSD in an Indian sample of trauma survivors based on prevailing models of PTSD defined in the DSM-IV-TR (APA, 2000), and to assess the relation between PTSD factors and gender.

Method:The sample comprised of 313 participants (55.9% female) from Jammu and Kashmir, India, who had experienced a natural disaster (N=200) or displacement due to cross-border firing (N=113).

Results:Three existing PTSD models—two four-factor models (Emotional Numbing and Dysphoria), and a five-factor model (Dysphoric Arousal) were tested using Confirmatory Factor Analysis with addition of gender as a covariate. The three competing models had similar fit indices although the Dysphoric Arousal model fit significantly better than Emotional Numbing and Dysphoria models. Gender differences were found across the factors of Re-experiencing and Anxious arousal.

Conclusions: Findings indicate that the Dysphoric Arousal model of PTSD was the best model; albeit the fit indices of all models were fairly similar. Compared to males, females scored higher on factors of Re-experiencing and Anxious arousal. Gender differences found across two factors of PTSD are discussed in light of the social milieu in India.

Charak, R., Armour, C., Elklit, A., Angmo, D., Elhai, J. D. & Koot, H. M.: (2014). Factor Structure of PTSD and Relationship with Gender in Trauma Survivors from India. European Journal of Psychotraumatology, 5:25547. Doi: 10.3402/ejpt.v5.25547.

The DSM-5 currently includes a dissociative-PTSD subtype within its nomenclature. Several studies have confirmed the dissociative-PTSD subtype in both American Veteran and American civilian samples. Studies have begun to assess specific factors which differentiate between dissociative vs. non-dissociative PTSD.

The current study takes a novel approach to investigating the presence of a dissociative-PTSD subtype in its use of European victims of sexual assault and rape (N=351). Utilizing Latent Profile Analyses, we hypothesized that a discrete group of individuals would represent a dissociative-PTSD subtype. We additionally hypothesized that levels of depression, anger, hostility, and sleeping difficulties would differentiate dissociative-PTSD from a similarly severe form of PTSD in the absence of dissociation.

Results concluded that there were four discrete groups termed baseline, moderate PTSD, high PTSD, and dissociative-PTSD. The dissociative-PTSD group encompassed 13.1% of the sample and evidenced significantly higher mean scores on measures of depression, anxiety, hostility, and sleeping difficulties. Implications are discussed in relation to both treatment planning and the newly published DSM-5.

Armour, C., Elklit, A., Lauterbach, D., & Elhai, J. D. (2014). The DSM-5 dissociative-PTSD subtype: Can levels of depression, anxiety, hostility, and sleeping difficulties differentiate between dissociative-PTSD and PTSD in rape victims? Journal of Anxiety Disorders, 28, 418–426. Doi: 10.1016/j.janxdis.2013.12.008

For over a century, the occurrence of dissociative symptoms in connection to traumatic exposure has been acknowledged in the scientific literature. Recently, the importance of dissociation has also been recognized in the long-term traumatic response within the DSM-5 nomenclature. Several studies have confirmed the existence of the dissociative posttraumatic stress disorder (PTSD) subtype. However, there is a lack of studies investigating latent profiles of PTSD solely in victims with PTSD.

Purpose and method. The current study investigates the possible presence of PTSD subtypes using latent class analysis (LCA) across two distinct trauma samples meeting caseness for DSM-5 PTSD based on self-reports (N = 787). Moreover, we assessed if a number of risk factors resulted in an increased probability of membership in a dissociative compared to a non-dissociative PTSD class.

Results. The results of LCA revealed a two-class solution with two highly symptomatic classes: a dissociative and a non-dissociative class across both samples. Increased emotion-focused coping increased the probability of individuals being grouped into the dissociative class across both samples. Social support reduced the probability of individuals being grouped into the dissociative class but only in the victims of motor vehicle accidents (MVA) suffering from whiplash.

Conclusions. The results are discussed in light of their clinical implications and suggest that the dissociative subtype can be identified in victims of incest and victims of MVA suffering from whiplash meeting caseness for DSM-5 PTSD.

Hansen, M.; Müllerová, J.; Elklit, A. & Armour, C. (2016). Can the dissociative PTSD subtype be identified across two distinct trauma samples meeting caseness for PTSD? Social Psychiatry and Psychiatric Epidemiology, 51(8), 1159-1169. Doi: 10.1007/s00127-016-1235-2

In the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), the symptom profile of posttraumatic stress disorder (PTSD) was expanded to include 20 symptoms. An alternative model of PTSD is outlined in the proposed 11th edition of the International Classification of Diseases (ICD-11) that includes just six symptoms.

Objectives and method: The objectives of the current study are: 1) to independently investigate the fit of the ICD-11 model of PTSD, and three DSM-5-based models of PTSD, across seven different trauma samples (N=3,746) using confirmatory factor analysis; 2) to assess the concurrent validity of the ICD-11 model of PTSD; and 3) to determine if there are significant differences in diagnostic rates between the ICD-11 guidelines and the DSM-5 criteria.

Results: The ICD-11 model of PTSD was found to provide excellent model fit in six of the seven trauma samples, and tests of factorial invariance showed that the model performs equally well for males and females. DSM-5 models provided poor fit of the data. Concurrent validity was established as the ICD-11 PTSD factors were all moderately to strongly correlated with scores of depression, anxiety, dissociation, and aggression. Levels of association were similar for ICD-11 and DSM-5 suggesting that explanatory power is not affected due to the limited number of items included in the ICD-11 model. Diagnostic rates were significantly lower according to ICD-11 guidelines compared to the DSM-5 criteria.

Conclusions: The proposed factor structure of the ICD-11 model of PTSD appears valid across multiple trauma types, possesses good concurrent validity, and is more stringent in terms of diagnosis compared to the DSM-5 criteria.

Hansen, M., Hyland, P., Armour, C., Shevlin, M. & Elklit, A. (2015). Less is more? Assessing the validity of the ICD-11 model of PTSD across multiple trauma samples. European Journal of Psychotraumatology, 6:28766. Doi: 10.3402/ejpt.v6.28766

The underlying latent structure of Posttraumatic Stress Disorder (PTSD) is widely researched. However, despite a plethora of factor analytic studies, no single model has consistently been shown as superior to alternative models. The two most often supported models are the Emotional Numbing and the Dysphoria models. However, a recently proposed five-factor Dysphoric Arousal model has been gathering support over and above existing models.

Data for the current study were gathered from Malaysian Tsunami survivors (N=250). Three competing models (Emotional Numbing/Dysphoria/Dysphoric Arousal) were specified and estimated using Confirmatory Factor Analysis (CFA). The Dysphoria model provided superior fit to the data compared to the Emotional Numbing model. However, using chi-square difference tests, the Dysphoric Arousal model showed a superior fit compared to both the Emotional Numbing and Dysphoria models.

In conclusion, the current results suggest that the Dysphoric Arousal model better represents PTSD's latent structure and that items measuring sleeping difficulties, irritability/anger and concentration difficulties form a separate, unique PTSD factor. These results are discussed in relation to the role of Hyperarousal in PTSD's on-going symptom maintenance and in relation to the DSM-5.

Armour, C., Ghazali, S. R. & Elklit, A. (2013). PTSD’s latent structure in Malayan tsunami victims: Assessing the newly proposed Dysphoric Arousal model. Psychiatry Research, 206(1):26-32. Doi: 10.1016/j.psychres.2012.09.012

Background: Refugees are known to have high rates of post-traumatic stress disorder (PTSD). Although recent years have seen an increase in the number of refugees from Arabic speaking countries in the Middle East, no study so far has validated the construct of PTSD in an Arabic speaking sample of refugees.

Methods: Responses to the Harvard Trauma Questionnaire (HTQ) were obtained from 409 Arabic-speaking refugees diagnosed with PTSD and undergoing treatment in Denmark. Confirmatory factor analysis was used to test and compare five alternative models.

Results: All four- and five-factor models provided sufficient fit indices. However, a combination of excessively small clusters, and a case of mistranslation in the official Arabic translation of the HTQ, rendered results two of the models inadmissible. A post hoc analysis revealed that a simpler factor structure is supported, once local dependence is addressed.

Conclusions: Overall, the construct of PTSD is supported in this sample of Arabic-speaking refugees. Apart from pursuing maximum fit, future studies may wish to test simpler, potentially more stable models, which allow a more informative analysis of individual items.

Vindbjerg, E.; Carlsson, J.; Mortensen, E.L.; Elklit, A. & Makransky, G. (2016): The latent structure of Posttraumatic Stress Disorder among Arabic-speaking refugees receiving psychiatric treatment in Denmark. BMC Psychiatry, 16:309. Doi 10.1186/s12888-016-0936-0.

The recent release of the DSM-5 comes with the division of posttraumatic stress disorder (PTSD) symptoms across four symptom clusters (American Psychiatric Association, 2013). This division is based on the support garnered by two four-factor models; Emotional Numbing (King et al., 1998) and Dysphoria (Simms et al., 2002) and a five-factor model; Dysphoric Arousal (Elhai et al., 2011). Much debate centered on the validity of the Dysphoria factor as a non-specific factor of PTSD within the Dysphoria model.

In line with this, we assessed relations between the four factors of the Dysphoria model (Simms et al., 2002) and positive (PA) and negative affect (NA) in natural disaster victims (N = 200) from Leh, India, using the PTSD checklist (PCL-S) and Positive and Negative Affect Schedule (PANAS short form). Confirmatory factor analysis was implemented to assess the best-fitting model for both the PCL (PTSD) and the PANAS (affect). Two optimal models (the Dysphoria model and a two-factor model for affect) were subsequently used to assess latent variable associations across constructs. It was hypothesized that differential associations between latent factors would be evident with the Dysphoria factor being highly correlated with negative affect compared to alternative PTSD factors.

Significant correlations were found between factors of the Dysphoria model and NA (0.52–0.65, p < 0.001). Comparing the association of pairs of PTSD factors with NA and PA, Wald’s tests revealed that no single PTSD factor was more related to NA than the other. Avoidance and Hyperarousal factors were correlated with PA. Results are discussed in line with literature questioning Dysphoria factor’s unique association with general distress.

Charak, R., Armour, C., Elklit, A., Koot, H. M., Elhai, J. D. (2014). Assessing the Latent Factor Association between the Dysphoria model of PTSD and Positive and Negative Affect in Trauma Victims from India. Psychological Injury & Law, 7, 122-130. Doi: 10.1007/s12207-014-9192-0

The three-factor structure of posttraumatic stress disorder (PTSD) specified by the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, is not supported in the empirical literature. Two alternative four-factor models have received a wealth of empirical support. However, a consensus regarding which is superior has not been reached.

A recent five-factor model has been shown to provide superior fit over the existing four-factor models. The present study investigated the fit of the five-factor model against the existing four-factor models and assessed the resultant factors' association with depression in a bereaved European trauma sample (N = 325). The participants were assessed for PTSD via the Harvard Trauma Questionnaire and depression via the Beck Depression Inventory.

The five-factor model provided superior fit to the data compared with the existing four-factor models. In the dysphoric arousal model, depression was equally related to both dysphoric arousal and emotional numbing, whereas depression was more related to dysphoric arousal than to anxious arousal.

Armour, C., O’Connor, M., Elklit, A. & Elhai, J (2013).: Assessing PTSD's Latent Structure in Elderly Bereaved European Trauma Victims: Evidence for a Five Factor Dysphoric and Anxious Arousal Model. Journal of Nervous and Mental Disease, 210(10), 901-906. Doi: 10.1097/NMD.0b013e3182a5befb

The project aimed to map the factor structure of PTSD among a group of adult Indians who survived a mud slide in India in August 2010.

Charak, R., Armour, C., Elklit, A., Koot, H. M., Elhai, J. D. (2014). Assessing the Latent Factor Association between the Dysphoria model of PTSD and Positive and Negative Affect in Trauma Victims from India. Psychological Injury & Law, 7, 122-130. Doi: 10.1007/s12207-014-9192-0

Charak, R., Armour, C., Elklit, A., Angmo, D., Elhai, J.D. & Koot, H. M. (2014) Factor structure of PTSD and Relationship with gender in Trauma Survivors from India. European Journal of Psychotraumatology, 5. Doi: 10.3402/ejpt.v5.25547

Tired african american soldier in military uniform sleeping in sofa at home

Complex PTSD

Recently, with the revised version of the International Classification of Diseases (ICD, 11th edition), we have been presented with a completely different way of understanding trauma and stress-related diagnoses, namely as two hierarchically related diagnoses for PTSD and Complex PTSD (CPTSD).

This classification system allows for some complementary understandings of a range of trauma-related phenomena. For example, we can understand prolonged trauma types as risk factors for the development of complex PTSD. Here you will find a collection of publications on complex PTSD.

Complex PTSD

The ICD-11 proposes different types of prolonged trauma as risk factors for complex PTSD (CPTSD). However, CPTSD's construct validity has only been examined in childhood abuse, and single trauma exposure samples. Thus, the extent to which CPTSD applies to other repeatedly traumatized populations is unknown.

This study examined ICD-11's PTSD and CPTSD across populations with prolonged trauma of varying interpersonal intensity and ages of exposure, including: 1) childhood sexual abuse, 2) adulthood trauma of severe interpersonal intensity (refugees and ex-prisoners of war), and 3) adulthood trauma of mild interpersonal intensity (military veterans, and mental health workers).

In support of the proposal, latent class analysis (N = 820) identified, a 4-class solution representing “PTSD”, “CPTSD”, and “non-pathological” classes, but also an “Anxiety symptoms” class, and an alternative 5-class solution, with a “Dissociative PTSD-subtype” class. ICD11's CPTSD was not exclusively associated with childhood abuse, but also with exposure to adulthood trauma of severe interpersonal intensity. Furthermore, all types of prolonged trauma were equally associated with the “Anxiety symptoms” class. Finally, of all the classes, the “CPTSD“ class was associated with the highest frequency of work-related functional impairment, indicating an association between the severity of prolonged trauma exposure and the level of posttraumatic residues.

Palic, S.; Zerach, G.; Shevlin, M.; Zeligman, Z.; Elklit, A. & Solomon, Z. (2016): Evidence of Complex Posttraumatic Stress Disorder (CPTSD) across populations with prolonged trauma of varying intensity and ages of exposure. Psychiatry Research 246, 692–699. Doi: 10.1016/j.psychres.2016.10.062

Background: The International Classification of Diseases, 11th version (ICD-11), proposes two related stress and trauma-related disorders, posttraumatic stress disorder (PTSD) and complex PTSD (CPTSD). A diagnosis of CPTSD requires that in addition to the PTSD symptoms, an individual must also endorse symptoms in three major domains: (1) affective dysregulation, (2) negative self-concepts, and (3) interpersonal problems. This study aimed to determine if the naturally occurring distribution of symptoms in three groups of traumatised individuals (bereavement, sexual victimisation, and physical assault) were consistent with the ICD-11, PTSD, and CPTSD specification. The study also investigated whether these groups differed on a range of other psychological problems.

Methods and Results: Participants completed self-report measures of each symptom group and latent class analyses consistently found that a three class solution was best. The classes were “PTSD only,” “CPTSD,” and “low PTSD/CPTSD.” These classes differed significantly on measures of depression, anxiety, dissociation, sleep disturbances, somatisation, interpersonal sensitivity, and aggression. The “CPTSD” class in the three samples scored highest on all the variables, with the “PTSD only” class scoring lower and the “low PTSD/CPTSD” class the lowest.

Conclusion: This study provides evidence to support the diagnostic structure of CPTSD and indicted that CPTSD is associated with a broad range of other psychological problems.

Elklit, A., Hyland, P. & Shevlin, M. (2014). Evidence of symptom profiles consistent with posttraumatic stress disorder and complex posttraumatic stress disorder in different trauma samples. European Journal of Psychotraumatology, 5: 24221. Doi: 10.3402/ejpt.v5.24221

Purpose: The World Health Organization's 11th revision to the International Classification of Diseases manual (ICD-11) will differentiate between two stress-related disorders: PTSD and Complex PTSD (CPTSD). ICD-11 proposals suggest that trauma exposure which is prolonged and/or repeated, or consists of multiple forms, that also occurs under circumstances where escape from the trauma is difficult or impossible (e.g., childhood abuse) will confer greater risk for CPTSD as compared to PTSD. The primary objective of the current study was to provide an empirical assessment of this proposal.

Methods: A stratified, random probability sample of a Danish birth cohort (aged 24) was interviewed by the Danish National Centre for Social Research (N = 2980) in 2008-2009. Data from this interview were used to generate an ICD-11 symptom-based classification of PTSD and CPTSD.
Results: The majority of the sample (87.1%) experienced at least one of eight traumatic events spanning childhood and early adulthood. There was some indication that being female increased the risk for both PTSD and CPTSD classification. Multinomial logistic regression results found that childhood sexual abuse (OR = 4.98) and unemployment status (OR = 4.20) significantly increased risk of CPTSD classification as compared to PTSD. A dose-response relationship was observed between exposure to multiple forms of childhood interpersonal trauma and risk of CPTSD classification, as compared to PTSD.

Conclusions: Results provide empirical support for the ICD-11 proposals that childhood interpersonal traumatic exposure increases risk of CPTSD symptom development.

Hyland, P., Murphy, J., Shevlin, M., Vallieres, F., McElroy, E., Elklit, A., Christoffersen, M. & Cloitre, M. (2017): Variation in post-traumatic response: the role of trauma type in predicting ICD-11 PTSD and CPTSD symptoms. Social Psychiatry & Psychiatric Epidemiology, 52(6):727-736. Doi: 10.1007/s00127-017-1350-8

With the publication of the International Statistical Classification of Diseases and Related Health Problems, 11th edition (ICD-11) due for release in 2018, a number of studies have assessed the factorial validity of the proposed post-traumatic stress disorder (PTSD) and complex (CPTSD) diagnostic criteria and whether the disorders are correlated but distinct constructs. As the specific nature of CPTSD symptoms has yet to be firmly established, this study aimed to examine the dimension of affect dysregulation as two separate constructs representing hyper-activation and hypo-activation.

Seven alternative models were estimated within a confirmatory factor analytic framework using the International Trauma Questionnaire (ITQ). Data were analysed from a young adult sample from northern Uganda (n = 314), of which 51% were female and aged 18–25 years. Forty per cent of the participants were former child soldiers (n = 124) while the remainder were civilians (n = 190). The prevalence of CPTSD was 20.8% and PTSD was 13.1%.

The results indicated that all models that estimated affective dysregulation as distinct but correlated constructs (i.e. hyper-activation and hypo-activation) provided satisfactory model fit, with statistical superiority for a seven-factor first-order correlated model. Furthermore, individuals who met the criteria for CPTSD reported higher levels of war experiences, symptoms of anxiety and depression, and somatic problems than those with PTSD only and no diagnosis. There was also a much larger proportion of former child soldiers that met the criteria for a CPTSD diagnosis. In conclusion, these results partly support the factorial validity of the ICD-11 proposals for PTSD and CPTSD in a non-Western culture exposed to mass violence. These findings highlight that more research is required across different cultural backgrounds before firm conclusions can be made regarding the factor structure of CPTSD using the ITQ.

Murphy, S., Dokkedahl, S., Shevlin, M. & Elklit, A. (2018). Testing Competing Factor Models of the Latent Structure of PTSD and CPTSD According to ICD-11. European Journal of Psychotraumatology, 9(1), 1457393. Doi: 10.1080/20008198.2018.1457393

Background: A new diagnosis, complex posttraumatic stress disorder (CPTSD), is set to be introduced in the 11th revision to the International Classification of Diseases (ICD-11). Studies have supported a unique group of trauma-exposed individuals who exhibit symptoms consistent with CPTSD proposals. No studies have yet tested the proposed latent symptom structure of CPTSD proposed for ICD-11. This study tests the factorial validity of CPTSD and assesses the role of a range of risk factors to predict CPTSD.

Method: A large sample (N = 453) of treatment-seeking adult victims of childhood sexual abuse completed self-report measures of CPTSD. Confirmatory factor analysis (CFA) was used to compare a set of alternative factor models of CPTSD.

Results: Just less than half of the sample met the diagnostic criteria for CPTSD (42.8%). CFA results supported the factorial validity of the ICD-11 proposals for CPTSD. Being female and experiencing a greater number of sexual abuse acts during childhood were more strongly associated with PTSD than CPTSD symptoms. Regarding symptoms, anxiety was more strongly associated with PTSD than CPTSD, whereas higher levels of dysthymia were more strongly associated with CPTSD than PTSD symptoms.

Conclusions: Results provide initial evidence regarding the factorial validity of the proposed ICD-11 model of CPTSD. In addition, current results support the proposals of the ICD-11 that exposure to abuse during early development is associated with a greater likelihood of CPTSD than PTSD. The study contributes to a growing body of empirical data supporting the construct validity of CPTSD as a unique diagnostic entity.

Hyland, P., Shevlin, M., Elklit, A., Murphy, J., Vallières, F., Garvert D.W., & Cloitre, M. (2016). An Assessment of the Construct Validity of the ICD-11 Proposals for Complex Posttraumatic Stress Disorder. Psychological Trauma 9(1), 1-9.

Objectives: This study investigated the frequency of traumatic experiences, prevalence rates of ICD-11 post-traumatic stress disorder (PTSD) and complex PTSD (CPTSD), and overlap with ICD-10 classified disorders in outpatient psychiatry.

Method: Overall, 165 Danish psychiatric outpatients answered the International Trauma Questionnaire, the Life Event Checklist, and the World Health Organization Well-being Index. ICD-10 diagnoses were extracted from the hospital record. Chi-square analysis, t-tests, and conditional probability analysis were used for statistical analysis.

Results: Nearly, all patients (94%) had experienced at least one traumatic event. CPTSD (36%) was more common than PTSD (8%) and had considerable overlap with ICD-10 affective, anxiety, PTSD, personality, adjustment and stress-reaction disorders, and behavioural and emotional disorders with onset usually occurring in childhood and adolescence. ICD-11 PTSD overlapped with ICD-10 anxiety, PTSD, adjustment and stress-reaction disorders, and behavioural and emotional disorders with onset usually occurring in childhood and adolescence. A subgroup of patients with ICD-10 PTSD (23%) did not meet criteria for ICD-11 PTSD or CPTSD.

Conclusion: Traumatic experiences are common. ICD-11 CPTSD is a highly prevalent disorder in psychiatric outpatients. One quarter with ICD-10 PTSD did not meet criteria for either ICD-11 PTSD or CPTSD. PTSD and CPTSD had considerable overlap with ICD-10 disorders.
Keywords: ICD-10; ICD-11; complex post-traumatic stress disorder; post-traumatic stress disorder; traumatic event.

Møller, L., Augsburger, M., Elklit, A., Søgaard, U., & Simonsen, E. (2020). Traumatic experiences, ICD-11 PTSD & Complex PTSD and the overlap with ICD-10 diagnoses. Acta Psychiatrica Scandinavica, 1-11. Doi: 10.1111/acps.13161.

Objectives: ICD-11 is expected to introduce a new diagnosis of C-PTSD, along with a revision of the current PTSD diagnosis. Are the suggested diagnostic tools for PTSD and C-PTSD valid in a developing country?
Method: The tools have been tested on former abducted and regular civilians in northern Uganda (n=314), who have been influenced by the civil war that lasted for more than two decades.

Results: The prevalence of either PTSD or C-PTSD was 36.6% and PTSD and C-PTSD was further found to correlate with symptoms of depression, anxiety and somatic complaints.
correlate with symptoms of depression, anxiety and somatic complaints.

Conclusion: Based on its findings the study concludes that the ICD-11 tools for PTSD and C-PTSDboth appear to be valid as suggested by both discriminant and convergent validation of the tools. However, future research can benefit from studying cultural aspects of these diagnoses.

Dokkedahl, S., Oboke, H., Ovuga, E. & Elklit, A. (2015). ICD-11 Trauma Questionnaires for PTSD and Complex PTSD: Validation among Civilians and Former Abducted Children in Northern Uganda. Journal of Psychiatry,18(6). Doi: 2378-5756.1000335

The International Classification of Diseases (ICD-11) is currently under development with proposed changes recommended for the posttraumatic stress disorder (PTSD) diagnosis and the inclusion of a separate complex PTSD (CPTSD) disorder. Empirical studies support the distinction between PTSD and CPTSD; however, less research has focused on non-western populations.

Objective: The aim of this study was to investigate whether distinct PTSD and CPTSD symptom classes emerged and to identify potential risk factors and the severity of impairment associated with resultant classes.
Methods: A latent class analysis (LCA) and related analyses were conducted on 314 young adults from Northern Uganda. Fifty-one percent were female and participants were aged between 18 and 25 years. Forty percent of the participants were former child soldiers (n=124) while the remaining participants were civilians (n=190).

Results: The LCA revealed three classes: a CPTSD class (40.2%), a PTSD class (43.8%), and a low symptom class (16%). Child soldier status was a significant predictor of both CPTSD and PTSD classes (OR=5.96 and 2.82, respectively). Classes differed significantly on measures of anxiety/depression, conduct problems, somatic complaints, and war experiences.

Conclusions: To conclude, this study provides preliminary support for the proposed distinction between PTSD and CPTSD in a young adult sample from Northern Uganda. However, future studies are needed using larger samples to test alternative models before firm conclusions can be made.

Highlights of the article
• Examine the validity of CPTSD in a non-western sample
• Separate PTSD and CPTSD classes emerged
• Former child soldiers were more strongly associated with the CPTSD class
• CPTSD class reported significantly higher levels of anxiety, depression, somatic complaints and conduct problems

Murphy, S., Elklit, A., Dokkedahl, S. & Shevlin, M. (2016): Testing the Validity of the proposed ICD-11 PTSD and complex PTSD criteria using a sample from Northern Uganda. European Journal of Psychotraumatology. 7: 32678. Doi: 10.3402/ejpt.v7.32678

Introduction: The WHO has proposed posttraumatic stress (PTSD) and Complex PTSD (CPTSD) trauma-related ‘sibling’-disorders in ICD-11. The proposal has received support from research among clinical and community samples alike but only few studies have tested the validity of these disorders in a sample of refugees using the International Trauma Questionnaire especially designed for assessment of ICD-11 PTSD and CPTSD.

Methods: Latent class analysis was used to test the validity of the ICD-11 PTSD and CPTSD distinction in a heterogeneous group of 284 highly symptomatic refugees registered for treatment at a Danish treatment-center.

Results: A two-class solution fit the data best. One group reported elevated levels of PTSD-symptoms and symptoms of affective dysregulation, and one group reported elevated levels of symptoms corresponding to CPTSD. The CPTSD group was considerably larger than the PTSD-group.

Discussion: The current study supports the ICD-11 distinction between PTSD and CPTSD in a sample of treatment-seeking refugees. The assistance of interpreters was needed for some of the participants which affected the reliability of the assessment.

Conclusion: The ICD-11 proposal for PTSD and CPTSD is supported in a heterogenous sample of refugees using the ITQ.

Vang, M.L., Jørgensen, S., Auning-Hansen, M. & Elklit, A. (2019). Testing the validity of ICD-11 PTSD and CPTSD among refugees in treatment using latent class analysis. Torture, 29(3), 27-45. Doi: org/10.7146/torture.v29i3.115367

Llose-up portrait of thoughtful female soldier in military uniform with ptsd sitting on couch and looking away

Acute stress disorder

Acute stress disorder and PTSD are often seen in relation to each other. This is due to the fact that the earliest a PTSD diagnosis can be made is 1 month after a traumatic event. However, it is not unknown for people to start experiencing PTSD symptoms some time after the traumatic event has taken place.
These PTSD-like symptoms that appear within the first month are described by DSM-IV as Acute Stress Disorder (ASD).

It is completely normal to experience certain stress-related symptoms after a traumatic experience. To be diagnosed with ASD, a person must fulfil certain criteria. In the DSM IV, these are described as follows:


A person must have experienced a traumatic event in which both of the following occurred:
• The person experienced, witnessed, or was confronted with an event in which there was a threat of or actual death or serious injury. The event may also have involved a threat to the physical well-being of the person or another person.
• The person reacted to the event with strong feelings of fear, helplessness or horror.


The person experiences at least three of the following dissociative symptoms during or after the traumatic event:
• Feeling numb or detached or having trouble experiencing emotions.
• Feeling numb or not fully aware of surroundings.
• Derealisation or feeling as if people, places and things are not real.
• Depersonalisation or feeling separate and detached from oneself.
• Dissociative amnesia or the inability to remember important parts of the traumatic event.


Re-experiencing symptoms (at least 1), such as having frequent thoughts, memories or dreams about the event. This can take the form of flashbacks or nightmares.


Below you can see a number of published studies on ASD conducted by the Danish Center for Psychotraumatology.

Acute Stress Disorder (ASD)

Numerous studies have identified risk factors for acute and long-term posttraumatic stress symptoms following traumatic exposure. However, little is known about whether there are common pathways to the development of acute stress disorder (ASD) and posttraumatic stress disorder (PTSD). Research suggests that a common path to ASD and PTSD may lie in peritraumatic responses and cognitions.

The results of structural equation modeling in a national sample of Danish bank robbery victims (N = 450) show that peritraumatic panic, anxiety sensitivity, and negative cognitions about self were significant common risk factors for both ASD severity and PTSD severity when controlled for the effect of the other risk factors. The strongest common risk factor was negative cognitions about self.

Future research should focus on replicating these results as they point to possible areas of preventive and treatment actions against the development of traumatic stress symptoms.

Hansen, M., Armour, C., Witmann, L., Elklit, A. & Shevlin, M. (2014). Is there a common pathway to developing ASD and PTSD symptoms? Journal of Anxiety Disorders, 28(8), 865-872. Doi:10.1016/j.janxdis.2014.09.019

Acute stress disorder (ASD) was first included in the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM–IV; American Psychiatric Association, 1994) to account for the psychological symptoms present during the one-month period between trauma exposure and a posttraumatic stress disorder (PTSD) diagnosis. The diagnostic criteria sets of both ASD and PTSD are similar; however, ASD includes additional dissociative items. Factor analytic research into ASD is rare, whereas there is a plethora of research on the factor structure of PTSD symptoms.

This study tested whether the latent structure of ASD is similar to the latent structure of PTSD. Five models were tested by using data from Danish rape victims (N = 380); a unidimensional model, the DSM–IV 4-factor ASD model, a King, Leskin, King, and Weathers (1998) replication model, a Simms, Watson, and Doebbeling (2002) replication model, and a 3-factor model. Model fit was assessed by using a number of fit indices, including the root-mean-square error of approximation, comparative fit index, Tucker-Lewis index, and standardized root-mean-square residual.

However, based on the fit indices, 3 models were deemed indistinguishable. Chi-square difference tests concluded that a 3-factor model and two 4-factor models did not differ in fit. Overall, the current 4-factor ASD latent structure proposed by the DSM–IV was not supported. A 3-factor structure was deemed preferential on the basis of parsimony. Furthermore, of all models, the unidimensional model provided the poorest fit to the data. These findings are pertinent given that the DSM-5 ASD task force is considering implementing either a 4-factor conceptualization or a unidimensional approach to the ASD diagnosis.

Armour, C., Elklit, A. & Shevlin, M. (2011). The Latent Structure of Acute Stress Disorder: A Post-traumatic Stress Disorder Approach. Psychological Trauma, 5 (1), 18-25. Doi: 10.1037/a0024848

Background: Since the introduction of Acute Stress Disorder (ASD) into the 4th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) research has focused on the ability of ASD to predict PTSD rather than focusing on addressing ASD's underlying latent structure. The few existing confirmatory factor analytic (CFA) studies of ASD have failed to reach a clear consensus regarding ASD's underlying dimensionality. Although, the discrepancy in the results may be due to varying ASD prevalence rates, it remains possible that the model capturing the latent structure of ASD has not yet been put forward. One such model may be a replication of a new five-factor model of PTSD, which separates the arousal symptom cluster into Dysphoric and Anxious Arousal. Given the pending DSM-5, uncovering ASD's latent structure is more pertinent than ever.

Objective: Using CFA, four different models of the latent structure of ASD were specified and tested: the proposed DSM-5 model, the DSM-IV model, a three factor model, and a five factor model separating the arousal symptom cluster.
Method: The analyses were based on a combined sample of rape and bank robbery victims, who all met the diagnostic criteria for ASD (N = 404) using the Acute Stress Disorder Scale.

Results: The results showed that the five factor model provided the best fit to the data.

Conclusions: The results of the present study suggest that the dimensionality of ASD may be best characterized as a five factor structure which separates dysphoric and anxious arousal items into two separate factors, akin to recent research on PTSD's latent structure. Thus, the current study adds to the debate about how ASD should be conceptualized in the pending DSM-5.

Hansen, M., Armour, C. & Elklit, A. (2012). Assessing a Dysphoric Arousal model of Acute Stress Disorder Symptoms in a Clinical Sample of Rape and Bank Robbery Victims. European Journal of Psychotraumatology, 3: 18201. Doi: 10.3402/ejpt.v3i0.18201

Objective: Acute stress disorder (ASD) was introduced into the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV; American Psychiatric Association, 1994) to identify posttraumatic stress reactions occurring within the first month after a trauma and thus help to identify victims at risk of developing posttraumatic stress disorder (PTSD). Since its introduction, research into ASD has focused on the prediction of PTSD, whereas only a few studies have investigated the latent structure of ASD. Results of the latter have been mixed. In light of the current proposal for the ASD diagnosis in the pending DSM-5, there is a profound need for empirical studies that investigate the latent structure of ASD prior to the DSM-5 being finalized.

Design: Based on previous factor analytic research, the DSM-IV, and the proposed DSM-5 formulation of ASD, four different models of the latent structure of ASD were specified and estimated.

Method: The analyses were based on a national study of bank robbery victims (N = 450) using the acute stress disorder scale.

Results: The results of the confirmatory factor analyses showed that the DSM-IV model provided the best fit to the data. Thus, the present study suggests that the latent structure of ASD may best be characterized according to the four-factor DSM-IV model of ASD (i.e., dissociation, re-experiencing, avoidance, and arousal) following exposure to bank robbery.

Conclusions: The results are pertinent in light of the pending DSM-5 and add to the debate about the conceptualization of ASD.

Hansen, M., Lasgaard, M. & Elklit, A. (2013). The Latent Factor Structure of Acute Stress Disorder following Bank Robbery: Testing Alternative Models in the light of the pending DSM-5. British Journal of Clinical Psychology, 52, 82-91. Doi: 10.1111/bjc.12002

Acute stress disorder (ASD) was introduced into the DSM-IV to recognize early traumatic responses and as a precursor of PTSD. Although the diagnostic criteria for ASD were altered and structured more similarly to the PTSD definition in DSM-5, only the PTSD diagnosis includes a dissociative subtype. Emerging research has indicated that there also appears to be a highly symptomatic subtype for ASD. However, the specific nature of the subtype is currently unclear.

The present study investigates the possible presence of ASD subtypes in a mixed sample of victims meeting caseness for DSM-5 ASD based on self-report following four different types of traumatic exposure (N=472). The results of latent profile analysis revealed a 5-class solution. The highly symptomatic class was marked by high endorsement on avoidance and dissociation compared to the other classes.

Findings are discussed in regard to its clinical implications including the implications for the pending the ICD-11 and the recently released DSM-5.

Hansen, M., Armour, C., Wang, L., Elklit, A. & Bryant, R. A. (2015). Assessing possible DSM-5 ASD subtypes in a sample of victims meeting caseness for DSM-5 ASD based on self-report following multiple forms of traumatic exposure. Journal of Anxiety Disorders, 31, 84-89. Doi: 10.1016/j.janxdis.2015.02.005


Last Updated 29.09.2023