Dimensional structure of DSM-5 posttraumatic stress symptoms: Support for a hybrid Anhedonia and Externalizing Behaviors model

Several revisions to the symptom clusters of posttraumatic stress disorder (PTSD) have been made in the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). Central to the focus of this study was the revision of PTSD's tripartite structure in DSM-IV into four symptom clusters in DSM-5. Emerging confirmatory factor analytic (CFA) studies have suggested that DSM-5 PTSD symptoms may be best represented by one of two 6-factor models: (1) an Externalizing Behaviors model characterized by a factor which combines the irritability/anger and self-destructive/reckless behavior items; and (2) an Anhedonia model characterized by items of loss of interest, detachment, and restricted affect. The current study conducted CFAs of DSM-5 PTSD symptoms assessed using the PTSD Checklist for DSM-5 (PCL-5) in two independent and diverse trauma-exposed samples of a nationally representative sample of 1484 U.S. veterans and a sample of 497 Midwestern U.S. university undergraduate students. Relative fits of the DSM-5 model, the DSM-5 Dysphoria model, the DSM-5 Dysphoric Arousal model, the two 6-factor models, and a newly proposed 7-factor Hybrid model, which consolidates the two 6-factor models, were evaluated. Results revealed that, in both samples, both 6-factor models provided significantly better fit than the 4-factor DSM-5 model, the DSM-5 Dysphoria model and the DSM-5 Dysphoric Arousal model. Further, the 7-factor Hybrid model, which incorporates key features of both 6-factor models and is comprised of re-experiencing, avoidance, negative affect, anhedonia, externalizing behaviors, and anxious and dysphoric arousal symptom clusters, provided superior fit to the data in both samples. Results are discussed in light of theoretical and empirical support for the latent structure of DSM-5 PTSD symptoms.     

Dissociative subtype of DSM-5 posttraumatic stress disorder in U.S. veterans

The Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) formally introduced a dissociative subtype of posttraumatic stress disorder (PTSD). This study examined the proportion of U.S. veterans with DSM-5 PTSD that report dissociative symptoms; and compared veterans with PTSD with and without the dissociative subtype and trauma-exposed controls on sociodemographics, clinical characteristics, and quality of life. Multivariable analyses were conducted on a nationally representative sample of 1484 veterans from the National Health and Resilience in Veterans Study (second baseline survey conducted September–October, 2013). Of the 12.0% and 5.2% of veterans who screened positive for lifetime and past-month DSM-5 PTSD, 19.2% and 16.1% screened positive for the dissociative subtype, respectively. Among veterans with PTSD, those with the dissociative subtype reported more severe PTSD symptoms, comorbid depressive and anxiety symptoms, alcohol use problems, and hostility than those without the dissociative subtype. Adjusting for PTSD symptom severity, those with the dissociative subtype continued to report more depression and alcohol use problems. These results underscore the importance of assessing, monitoring, and treating the considerable proportion of veterans with PTSD and dissociative symptoms.     

An evaluation of the DSM-5 factor structure for posttraumatic stress disorder in survivors of traumatic injury

Confirmatory factor analytic studies of the latent structure of DSM-5 PTSD symptoms using self-report data (Elhai et al., 2012, Miller et al., 2013) have found that the four-factor model implied by the DSM-5 diagnostic criteria provided adequate fit to their data. However, the fit of this model is yet to be assessed using data derived from gold standard structured interview measures. This study evaluated the fit of the DSM-5 four-factor model and an alternative four-factor model in 570 injury survivors six years post-injury using the Clinician Administered PTSD Scale (Blake et al., 1990), updated to include items measuring new DSM-5 symptoms. While both four-factor models fitted the data well, very high correlations between the ‘Intrusions’ and ‘Avoidance’ factors in both models and between the ‘Negative Alterations in Cognitions and Mood’ and ‘Arousal and Reactivity’ factors in the DSM-5 model and the ‘Dysphoria’ and ‘Hyperarousal’ factors in the alternative model were evident, suggesting that a more parsimonious two-factor model combining these pairs of factors may adequately represent the latent structure. Such a two-factor model fitted the data less well according to χ² difference testing, but demonstrated broadly equivalent fit using other fit indices. Relationships between the factors of each of the four-factor models and the latent factors of Fear and Anxious-Misery/Distress underlying Internalizing disorders (Krueger, 1999) were also explored, with findings providing further support for the close relationship between the Intrusion and Avoidance factors. However, these findings also suggested that there may be some utility to distinguishing Negative Alterations in Cognition and Mood symptoms from Arousal and Reactivity symptoms, and/or Dysphoria symptoms from Hyperarousal symptoms. Further studies are required to assess the potential discriminant validity of the two four-factor models.     

PTSD factor structure and relationship with self-construal among internally displaced persons

The present study examined the factor structure of six competing posttraumatic stress disorder (PTSD) models based on the recent changes in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) in a sample that, while highly vulnerable to PTSD, very few studies have focused on—Asians, particularly Filipino internally displaced persons (IDPs). In recognition of the role of culture in PTSD factor structure, we also investigated the associations of the factors of the best-fitting model with self-construal. A sample of 460 IDPs in government resettlement communities participated in the study. Results of confirmatory factor analyses revealed the seven-factor hybrid model composed of intrusion, avoidance, negative affect, anhedonia, externalizing behaviors, anxious arousal, and dysphoric arousal as the best-fitting model. Furthermore, it was found that associations between independent self-construal and PTSD factors were higher than that of interdependent self-construal and PTSD factors.     

Exploring differences between the ICD-11 and DSM-5 models of PTSD: Does it matter which model is used?

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.     

The underlying dimensions of DSM-5 posttraumatic stress disorder symptoms in an epidemiological sample of Chinese earthquake survivors

The current study investigated the underlying dimensions of DSM-5 PTSD symptoms in an epidemiological sample of Chinese earthquake survivors. The sample consisted of 810 females and 386 males, with a mean age of 47.9 years (SD = 10.0, range: 16–73). PTSD symptoms were assessed using the PTSD Checklist for DSM-5, and alternative models were evaluated with confirmatory factor analysis. Results indicated that a six-factor model comprised of intrusion, avoidance, negative affect, anhedonia, dysphoric arousal, and anxious arousal factors emerged as the best fitting model. The current findings add to limited literature on the latent structure of PTSD symptoms described in the recently released DSM-5, and carry implications for further trauma-related research and clinical practice.     

Posttraumatic stress disorder in DSM-5: estimates of prevalence and symptom structure in a nonclinical sample of college students

We empirically investigated recent proposed changes to the posttraumatic stress disorder (PTSD) diagnosis for DSM-5 using a non-clinical sample. A web survey was administered to 585 college students using the Stressful Life Events Screening Questionnaire to assess for trauma exposure but with additions for the proposed traumatic stressor changes in DSM-5 PTSD. For the 216 subjects endorsing previous trauma exposure and nominating a worst traumatic event, we administered the original PTSD Symptom Scale based on DSM-IV PTSD symptom criteria and an adapted version for DSM-5 symptoms, and the Center for Epidemiological Studies-Depression Scale. While 67% of participants endorsed at least one traumatic event based on DSM-IV PTSD's trauma classification, 59% of participants would meet DSM-5 PTSD's proposed trauma classification. Estimates of current PTSD prevalence were .4-1.8% points higher for the DSM-5 (vs. the DSM-IV) diagnostic algorithm. The DSM-5 symptom set fit the data very well based on confirmatory factor analysis, and neither symptom set's factors were more correlated with depression.     

Support for a novel five-factor model of posttraumatic stress symptoms in three independent samples of Iraq/Afghanistan veterans: a confirmatory factor analytic study

BackgroundA large body of confirmatory factor analytic studies of posttraumatic stress disorder (PTSD) symptoms has demonstrated the superiority of 4-factor dysphoria and emotional numbing models over the DSM-IV model. Recently, a novel 5-factor model, which separates the DSM-IV hyperarousal symptom cluster into distinct dysphoric and anxious arousal clusters, has been identified. However, little research has evaluated the best-fitting representation of PTSD symptoms in veterans of the Iraq and Afghanistan wars.MethodsConfirmatory factor analyses were used to examine the factor structure of the PTSD Checklist in three independent samples of Iraq/Afghanistan veterans, including two community samples and a treatment-seeking sample.ResultsIn all three samples, a novel model with five correlated factors reflecting symptoms of re-experiencing, avoidance, emotional numbing, dysphoric arousal, and anxious arousal provided a significantly better representation of PTSD symptoms than the DSM-IV, dysphoria, and numbing models. This model also showed evidence of “excellent fit” in the community samples according to empirically-defined benchmarks.ConclusionsThese findings suggest that PTSD symptomatology in both community and treatment-seeking Iraq/Afghanistan veterans may be best represented by a 5-factor model that separates the DSM-IV PTSD hyperarousal symptom cluster into distinct dysphoric arousal and anxious arousal clusters.     

PTSD factor structure differences between veterans with and without a PTSD diagnosis

This study examined differences in posttraumatic stress disorder's (PTSD) factor structure between veterans with and without a PTSD diagnosis. An archival dataset of 378 trauma-exposed Canadian veterans (mostly men) was used. The sample was divided into participants who met DSM-IV criteria for PTSD (n=230) and those who did not (n=148), based on a structured diagnostic interview. Confirmatory factor analysis was conducted to determine which empirically supported four-factor PTSD model best fit the data: (1) King, Leskin, King, and Weathers' (1998) Emotional Numbing model of Reexperiencing, Avoidance, Emotional Numbing and Hyperarousal factors, or (2) Simms, Watson, and Doebbeling's (2002) Dysphoria model of Reexperiencing, Avoidance, Dysphoria, and Hyperarousal factors. Results indicated that both models fit slightly better in the No-PTSD group. A series of measurement invariance tests demonstrated that the two groups varied on all parameters with the exception of factor loadings. The PTSD-group had larger intercepts, factor means, and residual error variance, suggesting that these participants had greater PTSD severity but more measurement error associated with their PTSD ratings. This study contributes to our understanding of how a PTSD diagnosis impacts the structure of PTSD symptoms at the latent level.     

Posttraumatic Stress Disorder,Hostile Cognitions,and Aggression in Iraq/Afghanistan Era Veterans

Objective: Most veterans with posttraumatic stress disorder (PTSD) are not violent, yet research has demonstrated that there is a substantial minority who are at increased risk. This study tested hypotheses regarding hyperarousal symptoms and hostile cognitions (i.e., “hostility”) as potential mechanisms of the association between PTSD and physical aggression in a longitudinal sample of Iraq/Afghanistan era veterans. Method: The sample included U.S. veterans between the ages of 18 and 70 who served in the military after September 11, 2001. At baseline, 301 veterans were evaluated for PTSD and completed self-report measures of hostility. At six-month follow-up 275 veterans and their family members or friends reported on the veterans’ physical aggression over the preceding interval. Regression models were used to evaluate relationships among PTSD status, hyperarousal cluster symptoms, and hostility at baseline, and physical aggression at six months. Bootstrapping was used to test for the mediation of baseline PTSD and six-month aggression by hostility. Results: PTSD significantly predicted physical aggression over six months, but hyperarousal cluster symptoms did not account for unique variance among the three clusters in the longitudinal model. Hostility partially mediated the association of PTSD at baseline and physical aggression at six months. Conclusions: Hostility may be a mechanism of the association of PTSD and physical aggression in veterans, suggesting the potential utility of targeting hostile cognitions in therapy for anger and aggression in veterans with PTSD.     

Do trauma type,stressful life events,and social support explain women veterans’ high prevalence of PTSD?

Objectives

To examine factors that account for women veterans’ higher prevalence of past-year DSM-5 posttraumatic stress disorder (PTSD) compared to women civilians and men veterans.

Methods

Cross-sectional analyses of the 2012–2013 National Epidemiologic Survey on Alcohol and Related Conditions-III (NESARC-III). Face-to-face interviews with 379 women veterans, 20,007 women civilians, and 2740 men veterans were conducted. Trauma type (child abuse, interpersonal violence, combat or war zone, and other), number of trauma types, past-year stressful life events, current social support, and DSM-5 PTSD were assessed using the Alcohol Use Disorder and Associated Disabilities Interview Schedule-5. Generalized linear models were used that accounted for the complex survey design.

Results

Women veterans had a higher unadjusted prevalence of past-year PTSD (11.40%) compared to their civilian (5.96%) and male (5.19%) counterparts. Individual predictor models indicated that the difference between women veterans’ and civilians’ prevalence of PTSD was attenuated when adjusting for number of trauma types, whereas the difference between men and women veterans was attenuated when adjusting for child abuse, interpersonal violence, and stressful life events. Nonetheless, while full adjustment in a multiple predictor model accounted for the difference in PTSD between women veterans and civilians, gender differences between men and women veterans remained.

Conclusions

Number of trauma types, type of trauma, and social factors may together help explain women veterans’ higher PTSD prevalence compared to women civilians, but do not fully account for differences between men and women veterans. Results highlight a need to explore additional explanatory factors and evaluate associations with longitudinal data.

     

Repetitive Transcranial Magnetic Stimulation for Depression and Posttraumatic Stress Disorder in Veterans With Mild Traumatic Brain Injury

ObjectivesMild traumatic brain injury (mTBI) is a signature injury of military conflicts and is prevalent in veterans with major depressive disorder (MDD) and posttraumatic stress disorder (PTSD). Although therapeutic transcranial magnetic stimulation (TMS) can reduce symptoms of depression and PTSD, whether traumatic brain injury (TBI) affects TMS responsiveness is not yet known. We hypothesized mTBI would be associated with higher pretreatment symptom burden and poorer TMS response.Materials and MethodsWe investigated a registry of veterans (N = 770) who received TMS for depression across the US Veterans Affairs system. Of these, 665 (86.4%) had data on TBI and lifetime number of head injuries while 658 had complete data related to depression outcomes. Depression symptoms were assessed using the nine-item Patient Health Questionnaire and PTSD symptoms using the PTSD Checklist for DSM-5. Linear mixed effects models and t-tests evaluated whether head injuries predicted symptom severity before treatment, and how TBI status affected clinical TMS outcomes.ResultsOf the 658 veterans included, 337 (50.7%) reported previous mTBI, with a mean of three head injuries (range 1–20). TBI status did not predict depressive symptom severity or TMS-associated changes in depression (all p’s > 0.1). TBI status was associated with a modest attenuation of TMS-associated improvement in PTSD (in patients with PTSD Checklist for DSM-5 scores > 33). There was no correlation between the number of head injuries and TMS response (p > 0.1).ConclusionsContrary to our hypothesis, presence of mTBI did not meaningfully change TMS outcomes. Veterans with mTBI had greater PTSD symptoms, yet neither TBI status nor cumulative head injuries reduced TMS effectiveness. Limitations include those inherent to retrospective registry studies and self-reporting. Although these findings are contrary to our hypotheses, they support the safety and effectiveness of TMS for MDD and PTSD in patients who have comorbid mTBI.     

The impact of PTSD symptoms on physical and mental health functioning in returning veterans

This study aimed to determine the unique impact of PTSD symptoms, beyond other frequently examined factors on physical and mental health functioning in a sample of returning veterans. Assessments of 168 returning OEF/OIF veterans conducted an average of six months following return from deployment included measures of emotional disorders and the Short Form (36) Health Survey. Hierarchical multiple regressions revealed significant, unique contribution of Clinician-Administered PTSD Scale (CAPS) score above all other predictors in the model (demographics, severity of trauma exposure, physical injury, substance abuse and depressive symptoms), for both the physical (8%) and mental (6%) health aggregate scores, along with significant prediction of physical health (4–10%) and mental health (3–7%) subscale scores. The only other significant predictors were age for physical health scores, and depressive symptoms for mental health scores. PTSD criterion B (re-experiencing) symptoms uniquely predicted reduced physical health functioning and higher experience of bodily pain, while criterion D (hyperarousal) symptoms uniquely predicted lower feelings of energy/vitality and poorer perceptions of emotional health.     

PTSD’s Underlying Dimensions in Typhoon Haiyan Survivors: Assessing DSM-5 Symptomatology-Based PTSD Models and Their Relation to Posttraumatic Cognition

The recent changes in posttraumatic stress disorder (PTSD) symptomatology in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) call for a re-examination of PTSD’s latent factor structure. The present study assessed six competing models of PTSD based on DSM-5 symptomatology using confirmatory factor analysis in a sample of young adult Filipino survivors of typhoon Haiyan, one of the strongest typhoons in the world ever recorded at the time of its landfall (N = 632). Furthermore, the differential relationships of the factors of the best-fitting model with posttraumatic cognitions were also investigated. Results showed the 7-factor hybrid model of PTSD comprised of intrusion, avoidance, negative affect, anhedonia, externalizing behaviors, anxious arousal, and dysphoric arousal, to be the best fitting model. In addition, the varying degrees of relationship with posttraumatic cognitions support the distinctiveness of each factor. These findings are pertinent in light of the changes in DSM-5 PTSD symptomatology, as well as in understanding the underlying dimensions of PTSD among Asian, particularly Filipino, survivors of a natural disaster.     

Post-september 11 admission symptoms and treatment response among veterans with posttraumatic stress disorder

OBJECTIVE: Evidence has been found of significant psychological distress after the terrorist attacks of September 11, 2001, even in communities that were not directly affected. Persons with preexisting posttraumatic stress disorder (PTSD) may be especially vulnerable to such distress. The authors examined clinical data on veterans who had a diagnosis of PTSD to determine whether the attacks exacerbated their symptoms. METHOD:S: Outcome-monitoring data were analyzed from a national sample of more than 9,000 veterans who were treated in specialized intensive PTSD programs of the Department of Veterans Affairs (VA) from March 11, 1999, to March 11, 2002. Analysis of variance was used to compare symptom levels at admission and clinical improvement during the six months before and six months after September 11 and in comparison with the same periods in 1999 and 2000. RESULTS: Veterans who were admitted after September 11, 2001, had less severe symptoms than those admitted before September 11, a pattern that was significantly different from previous years. Veterans who were followed up after September 11 showed significantly more improvement in PTSD symptoms than those who were followed up before then, which also represented a significant difference from previous years. CONCLUSION:S: VA patients with preexisting PTSD were, unexpectedly, less symptomatic at admission after September 11 than veterans admitted before September 11, and patients who had follow-up assessments after September 11 showed more improvement. It is possible that these veterans benefited from the shared feelings of national unity, pride, and patriotism in the months after September 11 as well as from the normalization of PTSD-like reactions by the news media and a sense of mastery at having past experience in coping with trauma.     

The dimensionality of PTSD symptoms and their relationship to health-related quality of life in Chinese earthquake survivors

The current study investigated the latent structure of PTSD symptoms with a sample of 326 Chinese survivors who lost their children during a deadly earthquake. The results of confirmatory factor analysis indicated that a five-factor intercorrelated model comprised of intrusion, avoidance, emotional numbing, dysphoric arousal, and anxiety arousal provided significant better fit than both the four-factor numbing model of King, Leskin, King, and Weathers (1998) and the four-factor dysphoria model of Simms, Watson, and Doebbeling (2002). Further analyses with structural equation modeling showed that the PTSD factors were differentially associated with external measures of psychosocial and physical health-related quality of life. The findings provide further empirical support for the novel five-factor PTSD model, and carry implications for conceptualizing and assessing PTSD for the upcoming DSM-5.     

Latent profiles of DSM-5 PTSD symptoms and the “Big Five” personality traits

Typologies of DSM-5 PTSD symptoms and personality traits were evaluated in regard to coping styles and treatment preferences using data from 1266 trauma-exposed military veterans of which the majority were male (n = 1097; weighted 89.6%). Latent profile analyses indicated a best-fitting 5-class solution; PTSD asymptomatic and emotionally stable (C1); predominant re-experiencing and avoidance symptoms and less emotionally stable (C2); subsyndromal PTSD (C3); predominant negative alterations in mood/cognitions and combined internalizing–externalizing traits (C4); and high PTSD severity and combined internalizing–externalizing traits (C5). Compared to C5, C1 members were less likely to use self-distraction, denial, and substance use and more likely to use active coping; C2 and C4 members were less likely to use denial and more likely to use behavioral disengagement; C3 members were less likely to use denial and instrumental coping and more likely to use active coping; most classes were less likely to seek mental health treatment. Compared to C1, C2 members were more likely to use self-distraction, substance use, behavioral disengagement and less likely to use active coping; C3 members were more likely to use self-distraction, and substance use, and less likely to use positive reframing, and acceptance; and C4 members were more likely to use denial, substance use, emotional support, and behavioral disengagement, and less likely to use active coping, positive reframing, and acceptance; all classes were more likely to seek mental health treatment. Emotional stability was most distinguishing of the typologies. Other implications are discussed.     

Post-traumatic Stress Disorder in Older U.S. Military Veterans: Prevalence,Characteristics, and Psychiatric and Functional Burden

ObjectiveTo characterize the prevalence, characteristics, and comorbidities of subthreshold and full post-traumatic stress disorder (PTSD) in older U.S. military veterans.Design and SettingA nationally representative web-based survey of older U.S. military veterans who participated in the National Health and Resilience in Veterans Study (NHRVS) between November 18, 2019 and March 8, 2020.ParticipantsU.S. veterans aged 60 and older (n = 3,001; mean age = 73.2, SD: 7.9, range: 60–99).MeasurementsPTSD was assessed using the PTSD Checklist for DSM-5. Self-report measures assessed sociodemographic characteristics, trauma exposures, suicidal behaviors, psychiatric and substance use disorders, as well as mental, cognitive, and physical functioning. Multivariable analyses examined correlates of subthreshold and full PTSD.ResultsThe vast majority of the sample (n = 2,821; 92.7%) reported exposure to one or more potentially traumatic events. Of those exposed to such events, 262 (9.6%, 95% confidence interval [CI]: 8.4%–10.9%) and 68 (1.9%, 95% CI: 1.3%–2.6%) screened positive for subthreshold and full PTSD, respectively. The prevalence of subthreshold and full PTSD was significantly higher in female veterans and veterans who use VA as their primary healthcare. Subthreshold and full PTSD groups endorsed more adverse childhood experiences and total traumas than the no/minimal PTSD symptom group, the most common traumatic experiences endorsed were combat exposure, physical or sexual assault, and life-threatening illness or injury. Veterans with subthreshold and full PTSD were also more likely to screen positive for depression, substance use disorders, suicide attempts, nonsuicidal self-injury, and suicidal ideation, and reported lower mental, cognitive, and physical functioning.ConclusionSubthreshold PTSD and full PTSD are prevalent and associated with substantial clinical burden in older U.S. veterans. Results underscore the importance of assessing both subthreshold and full PTSD in this population.     

Neuropsychological Findings in Combat-Related Posttraumatic Stress Disorder

Previous research investigating whether combat-related Posttraumatic Stress Disorder (PTSD) is associated with impaired neuropsychological functioning has yielded inconsistent findings. The present study addressed many methodological limitations of previous research. Neuropsychological measures of intellectual ability, learning, memory, attention, visuospatial ability, executive functioning, language, and psychomotor speed were compared in four groups of early middle-aged community dwelling veterans. The four demographically comparable groups were: (a) those with current PTSD symptoms (n =80); (b) those with a prior history of PTSD but not currently experiencing active PTSD symptoms (n =80); (c) a non-PTSD psychiatrically matched control group (n =80); and (d) a normal control group (n =80). Results indicated that the four groups did not statistically differ on the neuropsychological measures and that veterans with PTSD perform similarly to demographically matched controls. Results further suggested that the cognitive difficulties previously linked to PTSD may actually have been secondary to preexisting individual differences or other clinical conditions coexisting with PTSD.