Does Prior Civilian Trauma Moderate the Relationship Between Combat Trauma and Post-deployment Mental Health Symptoms?

Abstract

In addition to combat trauma, childhood and adult non-military, interpersonal trauma exposures have been linked to a range of psychiatric symptoms (e.g., alcohol use problems, posttraumatic stress disorder [PTSD], depression symptoms) in veterans. However, few studies simultaneously explore the associations between these civilian and combat trauma types and mental health outcomes. Using a sample of combat-exposed veterans who were previously deployed to Iraq and Afghanistan (N = 302), this study sought to (a) understand the independent associations of civilian interpersonal trauma (i.e., childhood trauma and non-military adult trauma) and combat-related trauma with post-deployment alcohol use, PTSD symptoms, and depressive symptoms, respectively and (b) to examine the interactive effects of trauma type to test whether childhood and non-military adult trauma moderate the association of combat trauma with these outcomes. A path analytic framework was used to allow for the simultaneous prediction of these associations. In the final model non-military adult trauma and combat trauma were found to be significantly associated with PTSD symptoms and depression symptoms, but not average amount of drinks consumed per drinking day. Childhood trauma was not associated with any outcomes (i.e., PTSD symptoms, depression symptoms, average amount of drinks consumed per day). Only combat trauma was significantly associated with average amount of drinks consumed per day. Results underscore the importance of assessing multiple trauma types and considering trauma as a non-specific risk factor, as different trauma types may differentially predict various mental health outcomes other than PTSD. Further, results highlight the noteworthiness of considering co-occurring outcomes within the veteran community. Limitations, future directions, and implications of diversity are discussed.

Keywords

PTSD alcohol and drugs war Hx of child abuse < PTSD violence exposure

Introduction

Alcohol use problems, posttraumatic stress disorder (PTSD), and major depressive disorder (MDD) are all highly prevalent among service members and veterans. Large-scale survey studies from the Vietnam and Iraq and Afghanistan wars found a high prevalence of alcohol consumption and other problematic alcohol use phenotypes including binge drinking (30%; Boscarino, 1981; Meadows et al., 2018), hazardous alcohol use (40%; Calhoun et al., 2008), and possible alcohol use disorder (AUD; 22%; Meadows et al., 2018). In a meta-analysis that included over 4 million Iraq and Afghanistan war veterans, prevalence of PTSD diagnosis was 23% (Fulton et al., 2015). Similar to PTSD, depression is highly prevalent among Iraq and Afghanistan veterans (17%; Seal et al., 2009).

Prior research has also highlighted high levels of psychiatric co-occurrence between alcohol use problems, PTSD, and depression symptoms in veterans (Cadigan et al., 2017; Dedert et al., 2009). This is important to understand and address, as those exhibiting a co-occurrence of substance use and mental health disorders are likely to experience higher symptom severity, require specialized treatment, and have poorer treatment outcomes (Seal et al., 2011). Additionally, co-occurring substance use and other mental health symptoms are associated with increased risk of physical and psychosocial health outcomes such as chronic pain, respiratory and cardiovascular diseases, marital instability, and unemployment (Breslau et al., 2003; Kessler, 2000; Sareen et al., 2007). The frequent co-occurrence of these post-deployment conditions, as well as their associated clinical implications, calls for study designs that account for their interrelations. Further, in veterans of the Iraq and Afghanistan conflicts, these psychiatric outcomes are also frequently comorbid with mild traumatic brain injury (mTBI), which adds to the clinical complexity (Corrigan & Cole, 2008; Grossbard et al., 2017; McHugo et al., 2017).

An abundance of research has documented the association of combat trauma specifically with later psychiatric outcomes (e.g., PTSD and depression symptoms; Dedert et al., 2009; Hassija et al., 2012) and alcohol misuse (Hassija et al., 2012; Kelley et al., 2013; Wilk et al., 2010). However, it is important to recognize that veterans represent a highly trauma-exposed population above and beyond combat trauma and broader deployment-related trauma (Forbes et al., 2013; Voorhees et al., 2012). A more limited line of research has examined the impact of non-military, particularly interpersonal (i.e., trauma involving physical neglect, emotional abuse, emotional neglect, physical or sexual abuse) trauma types in deployed veterans of Iraq and Afghanistan conflicts on mental health outcomes. The examination of individual trauma types is important given evidence that trauma type (e.g., interpersonal vs. accidental) and timing (e.g., childhood vs. adult) differentially impact risk for the development of psychopathology (Dunn et al., 2017; Liu et al., 2017). Factor analyses have identified a distinction between interpersonal and non-assaultive trauma types (Benjet et al., 2016), with the former often being associated with greater risk for developing PTSD, MDD, and substance use disorders (Forbes et al., 2014). Further, childhood traumatic events, perhaps because they occur during more sensitive developmental periods, are often associated with an elevated risk of developing depression and anxiety disorders in adulthood (Dunn et al., 2017). When examining the impact of interpersonal trauma types in veterans, one study found that the experience of a physical attack (e.g., beaten/badly hurt by a stranger, robbery) after the military was associated with PTSD, depression symptom severity, and alcohol use problems (Clancy et al., 2006). In samples of troops deployed to Iraq and Afghanistan, adverse childhood experiences, including childhood sexual abuse, have been shown to be associated with an increased likelihood of PTSD and depression (Cabrera et al., 2007). Other work has demonstrated that childhood physical assault was only associated with PTSD and MDD co-occurrence, but not with PTSD alone in veterans who served post September 11, 2001 (Dedert et al., 2009).

However, much of the extant work examines the impact of childhood and post-military traumatic events in isolation. When examined simultaneously, however, the patterns of findings are conflicting. Some studies have found that after accounting for combat exposure, child and adult interpersonal trauma were not significantly associated with PTSD symptoms, depression symptoms, or alcohol misuse in a sample of women veterans (Hassija et al., 2012), nor was childhood interpersonal trauma significantly associated with alcohol use in male National Guard members (Vest et al., 2018). Conversely, other studies have found that adverse childhood experiences remain associated with PTSD symptoms (Cabrera et al., 2007; van Voorhees et al., 2012) as well as alcohol misuse (Clarke-Walper et al., 2014) in military samples, even after accounting for combat exposure. These inconsistencies in the literature may result from a failure to account for the high co-occurrence among various outcomes (e.g., alcohol use, depression, and PTSD). For example, in examining the simultaneous effects of pre-military, non-combat military, post-military, and combat trauma, Kelley et al. (2013) found an association between all trauma categories with depression and PTSD, but only combat and post-military trauma were associated with alcohol use problems. However, few studies have accounted for multiple outcomes in relation to various trauma types within the same sample. Thus, there remains a need to further examine the joint effects of different types of trauma on multiple outcomes.

Further, as evidence suggests a dose-dependent relationship, wherein cumulative stress (i.e., greater trauma exposure) increases the risk for negative outcomes (Dedert et al., 2009; Kim et al., 2014; Sinha, 2008) there is also a need to examine the potential for interaction effects of combat trauma and childhood or adulthood non-combat/interpersonal trauma. This work has been limited to date, and the results of existing studies either did not find evidence of an interaction effect (Fritch et al., 2010) or were contrary to expectations of additive risk. Cabrera et al. (2007) examined the interactive effect of childhood trauma and combat trauma on PTSD and depression symptoms, while Vest et al. (2018) examined the effect on alcohol use problems. Both found evidence for a significant interaction effect, such that greater combat exposure was associated with psychiatric outcomes in the presence of low childhood trauma (Vest et al., 2018) or no adverse childhood experiences (Cabrera et al., 2007). The authors suggested this unexpected interaction effect may be explained by a possible ceiling effect, wherein individuals with prior childhood trauma are not further affected by combat, or that individuals with childhood trauma histories evidence lower reactivity to combat (Cabrera et al., 2007). Alternatively, Stein et al. (2005) found that among individuals with high combat exposure, increasingly severe childhood trauma was associated with less severe PTSD symptoms (Stein et al., 2005), with the authors suggesting a possible inoculation effect. The former two study samples included active duty service members following trauma, and the latter assessed Gulf War veterans, while the present study assesses veterans of the Iraq and Afghanistan conflicts. Further, non-military adult traumas have received less attention in this literature to date. A limitation of these studies, as well as others reviewed here, is that PTSD symptoms, depression symptoms, and alcohol consumption have been examined separately, despite evidence that these outcomes show frequent co-occurrence (Cadigan et al., 2017; Dedert et al., 2009).

The goals of the current study were to expand upon the literature concerning the impact of different trauma types on a range of post-military mental health outcomes by examining the joint and interactive effects of childhood, non-military adult, and combat trauma on the frequently co-occurring mental health outcomes of alcohol consumption, PTSD, and depression. A path analytic framework was employed to allow for the simultaneous prediction of these correlated outcomes. The first aim of this study was to examine the association of childhood, non-military adult, and combat trauma on post-military mental health outcomes of alcohol consumption, PTSD symptom severity, and depression symptoms. It was hypothesized that the experience of childhood and non-military adult trauma will be positively associated with increased alcohol consumption, PTSD symptoms, and depression symptoms above and beyond the effects of combat trauma. The second aim of this study was to examine whether childhood and non-military adult trauma moderated the relationship between combat trauma and post-military mental health outcomes. Based on the findings of previous literature (i.e., Cabrera et al., 2007; Vest et al., 2018), implicating a possible ceiling effect as compared to an additive, dose-dependent reaction, it was hypothesized that childhood and non-military adult trauma would moderate the association of combat trauma on outcomes, such that greater combat trauma will be most impactful on outcomes in the presence of low childhood or non-military adult trauma. Demographic characteristics, number of deployments, and mTBI status were included as covariates given their associations with our outcomes of interest.

Methods

Participants and Procedures

Participants were recruited for the parent study, through the local VA medical center and community, which examined the effect of trauma on stress reactivity and subsequent drinking behavior in veterans of the Iraq and Afghanistan conflicts. To be eligible for the parent study, participants had to be between the ages of 21–40, have served in the military post September 11, 2001, and be regular drinkers, but not seeking treatment for or exhibiting symptoms of alcohol dependence. A phone-screening was conducted to determine eligibility for the study. Participants were excluded from the parent study if they had current MDD and substance abuse or dependence. Participants were also excluded if they had a self-reported history of moderate to severe TBI, but were enrolled if they had mTBI, assessed using a brief TBI screening tool (Schwab et al., 2006). Participants who provided verbal consent to screening questions and met the inclusion/exclusion criteria after the initial screening were invited to participate in an in-person office visit. After providing in-person informed consent, participants completed self-report questionnaires, a clinical interview, and computerized behavioral tasks. The study was approved by both the Virginia Commonwealth University and the Hunter Holmes McGuire VA Medical Center Institutional Review Boards.

For the present study, participants were selected who had experienced a potentially traumatic event during deployment (N = 302). The present sample was 88.7% male and 64.9% white, with a mean age of 30.54 (SD = 4.48; refer to Table 1 for more descriptive statistics).

Table 1.

Descriptive Statistics and Correlations Among Study Variables (n = 302).

Variable	Mean (SD)or n (%)	Skew	Kurtosis	1	2	3	4	5	6	7	8	9	10	11
Gender (ref. male)	268 (88.7)	–	–	–
Race(ref. white)	302 (67.6)	–	–	.11	–
Number of deployments	1.94(1.22)	2.14	5.86	–.05	.03	–
Age	30.54 (4.48)	.30	–.72	–.03	.18**	.26***	–
Mild traumatic brain injury(Ref. mTBI)	116(38.4)	–	–	.01	–.06	–.02	–.02	–
Number of childhood traumas(range 0–4)	1.12 (1.03)	.50	–.68	.12*	.00	.07	.02	–.04	–
Number of non-military adult traumas(range 0–7)	1.98(1.39)	.36	–.35	–.07	.05	–.07*	.04	.08	.28***	–
Number of combat traumas(range 0–15)	7.14 (4.09)	.16	–1.07	–.29***	–.06	.17**	.01	.25**	.01	.11	–
CAPS (PTSD symptom severity)(range 0–122)	28.75 (23.72)	.96	.32	.03	.00	–.001	–.02	.20**	.04	.16**	.35**	–
BDI (Depressive symptoms)(range 0–39)	8.54 (7.67)	1.16	1.40	.02	–.06	–.05	.07	.16*	.02	.17**	.13*	.61**	–
Average drinks per day (alcohol use)	1.41 (1.46)	2.44	7.00	–.08	.01	.09	–.04	.08	–.01	.02	.18**	.18**	.10	–

Notes. * p < .05, ** p < .01, *** p < .001. Gender: Male = 1, Female = 2; Race: White = 0, Other = 1.

Measures

Demographic and military-related information.

Demographic information was assessed through a self-report questionnaire administered during the office visit and included age, gender, income, ethnicity, education, marital status, employment status, and military history including rank and branch, as well as number of times deployed.

PTSD symptom severity.

The Clinician Administered PTSD Scale for DSM-IV (CAPS; Blake et al., 1995) is a structured diagnostic interview used to assess current and lifetime PTSD, which exhibits strong internal consistency across items of .94 (Blake et al., 1995). The CAPS was conducted by postdoctoral fellows and master’s level social workers, and doctoral psychology students and was assessed based on the combat-related event the participant deemed most traumatic. If participants met DSM-IV criterion A for a deployment-related event (i.e., threat to life or physical integrity, subjective distress), they were assessed for current PTSD symptoms (i.e., in the past month) related to this event. In the current study, total symptom severity in the past month was used as the outcome, and the CAPS showed high inter-rater reliability (i.e., ICC (1,1) = .99).

Depression symptoms.

The Beck Depression Inventory-II (BDI-II; Beck et al., 1996) was used to assess depressive symptoms within the past two weeks. This self-report measure consists of 21 questions that highlight either a cognitive or somatic symptom of depression, rated from 0 (not present; e.g., “I do not feel sad”) to 3 (high severity; e.g., “I am so sad and unhappy that I can’t stand it”). This measure possesses high internal consistency, with a Cronbach’s alpha of .90 in this sample. A total sum score on the BDI was used to capture depression symptoms.

Alcohol consumption.

The Timeline Followback (TLFB) Measure (Sobell & Sobell, 1992) assesses drinking behavior from the past 30 days (i.e., quantity and frequency of drinks), with test–retest reliability over .85 (Sobell et al., 1996). The average number of drinks per drinking day was used to measure the quantity of drinks a participant endorsed drinking within the past 30 days.

Trauma exposure.

The Deployment Risk and Resiliency Inventory (DRRI; King et al., 2003) is a set of 14 scales each measuring deployment-related risk and resilience factors. The DRRI scales have demonstrated good to modest estimates of internal consistency, which are generally expected for measures of discrete stressor events (Bollen & Lennox, 1991; Cleary, 1981) as well as strong criterion-related validity when correlated with mental (i.e., posttraumatic stress symptoms, depression symptoms) and physical health symptoms (i.e., count of physical symptoms) and overall mental health and cognitive functioning (Vogt et al., 2008). The two DRRI scales used in the present study were Combat Experiences and Pre-deployment Events (slightly adapted for current study aims, further described).

The Combat Experiences scale is a 15-item measure where individuals mark whether they have experienced each combat-related circumstance on a yes/no basis. This scale captures broad aspects of combat experiences, for example, “I went on combat patrols or missions” and “I killed or think I killed someone in combat.”

The Pre-deployment Events scale was modified to capture both childhood and non-military adult traumatic events. To capture non-military adult traumatic events, items directly related to previous combat were removed, resulting in a 7 item measure capturing non-military potentially traumatic events (e.g., “Been robbed or had my home broken into”). Participants indicated whether they had or had not experienced each event on a yes/no basis. For childhood interpersonal traumatic events, items involving combat and adult traumas were removed, resulting in a 4-item scale capturing potentially traumatic childhood events (e.g., “Been physically punished by my parent or caregiver”). Participants indicated whether they had or had not experienced each event on a yes/no basis. These scales were used to create two (mean centered) interaction terms (i.e., ChildxCombat and AdultxCombat).

Data Analytic Plan

Prior to conducting analyses, data were checked for distributional assumptions, and all continuous predictors were mean centered to increase interpretability and reduce non-essential multicollinearity. To test the study aims, path analyses were conducted in Mplus Version 8 (Muthén & Muthén, 2017) to examine whether combat trauma, childhood trauma, and non-military adult trauma exert main or interaction effects on current PTSD symptoms, depression symptoms, and average amount of drinks per day. We chose a path analytic framework in order to simultaneously include the interrelations among multiple, correlated predictors in the prediction of multiple, correlated outcomes. To test study hypotheses, the model was estimated using all covariates (i.e., gender, race, age, number of deployments, mTBI status), main effect predictors (i.e., childhood trauma, non-military adult trauma, and combat trauma), interactions (i.e., childhood trauma by combat trauma, non-military adult trauma by combat trauma) and outcomes (i.e., PTSD symptoms, depression symptoms, average amount of drinks per day), with non-significant (p < .05) interactions trimmed.

Results

Mean scores and prevalence of outcomes and trauma types are presented in Table 1. In terms of zero-order correlations among study variables, as expected, there were positively significant or marginally significant associations among each of the outcomes (i.e., PTSD symptoms, depression symptoms, average drinks per day; refer to Table 1).

Results of the full model, including all participants, covariates and interactions are presented in the top panel of Table 2. Of note, all models were fully saturated, so no fit indices are presented here. Neither of the interaction terms (i.e., Child x Combat and Adult x Combat) was significantly associated with any of the outcomes (i.e., current PTSD symptoms, depression symptoms, average drinks per day); thus, these were trimmed for the final model.

Table 2.

Path Analysis Results Examining the Association of Trauma Types with Average Drinks per Day, PTSD Symptoms, and Depressive Symptoms (N = 302).

	Average Drinks Per Day			PTSD Symptoms			Depression Symptoms
Predictors	β	SE B ^a	95% CI	β	SE B	95% CI	β	SE B	95% CI
Model 1: Initial model, all variables
Race (ref. white)	.03	.19	–.07, .13	.01	2.84	–.09, .10	–.05	.95	–.15, .05
Gender (ref. male)	–.04	.28	–.14, .06	.13*	4.32	.04, .23	.05	1.41	–.05, .15
Age	–.07	.02	–.16, .04	–.01	.30	–.10, .09	.11	.10	–.01, .21
Number of times deployed	.06	.07	–.03, .17	–.04	1.12	–.13, .06	–.06	.37	–.16, .04
mTBI	.04	.18	–.07, .14	.08	2.75	–.01, .18	.11	.93	.003, .21
Childhood trauma	.01	.09	–.11, .09	–.01	1.32	–.11, .08	–.02	.45	–.12, .08
Non-military adult trauma	.01	.07	–.10, .11	.12*	.98	.03, .22	.15**	.32	.05, .25
Combat trauma	.15**	.02	.04, .26	.37***	.34	.28, .46	.13**	.11	.03, .24
ChildxCombat	–.02	.02	–.12, .09	–.02	.32	–.12, .08	–.11	.11	–.22, –.01
AdultxCombat	.00	.02	–.10, .11	–.07	.24	–.12, .03	.003	.08	–.10, .10
Model 2: Trimmed final model, without interactions^b
Race (ref. white)	.03	.18	–.07, .12	.01	2.80	–.08, .10	–.07	.93	–.17, .03
Gender (ref. male)	–.04	.28	–.14, .06	.13*	4.29	.04, .23	.06	1.41	–.04, .15
Age	–.07	.02	–.16, .03	–.01	.30	–.10, .08	.10	.10	–.001, .20
Number of times deployed	.07	.07	–.03, .17	–.04	1.1	–.14, .05	–.07	.37	–.17, .03
mTBI	.03	.18	–.07, .14	.08	2.74	–.01, .18	.10	.93	–.004, .20
Childhood trauma	–.01	.09	–.11, .09	–.01	1.32	–.10, .09	–.02	.45	–.12, .08
Non-military adult trauma	–.01	.07	–.09, .11	.13*	.98	.04, .22	.16** .32	.06, .26
Combat trauma	.15*	.02	.04, .26	.37***	.35	.28, .46	.14*	.12	.03, .24

Notes: *** p < .001, ** p < .01, * p < .05. Gender: Male = 1, Female = 2; Race: White = 0, Other = 1.

^aPer suggestions by Mplus creators in the final model results, standardized coefficients and unstandardized standard errors and p-values are presented.

^bA follow-up analysis was conducted to only include participants without missing data for any of the predictor variables (N = 277). Even with a smaller sample size, this model showed the same pattern of results.

Results of the trimmed, final model, removing the non-significant interaction terms (refer to Table 2, middle panel) followed the same pattern. For PTSD, non-military adult and combat traumas were significantly associated, such that more traumas were associated with greater PTSD symptoms. Childhood trauma was not associated with PTSD. Non-military adult and combat traumas were also significantly associated with depression symptoms, such that more traumas were related to greater depression symptoms. Childhood trauma was not associated with depression symptoms. For the average drinks per day outcome, only combat trauma was significantly associated, such that more combat trauma was related to more drinks consumed per drinking day. It is noted that the model was also run with only participants without missing data for any of the predictor variables (N = 277). Even with a smaller sample size, this model showed the same pattern of results.

In order to better determine whether associations were specific to childhood or adulthood trauma types or were simply due to greater trauma load, instead of separating childhood and adult non-military traumas into separate variables, a combined non-military (civilian) trauma variable was used as a predictor in follow-up analyses. The results of this analysis again followed the same pattern, with the combined non-military trauma associated with psychiatric, but not alcohol, outcomes. There was only one covariate that predicted any of the outcomes in all models. Specifically, gender was significantly associated with PTSD, such that female participants were more likely to have current PTSD symptoms, compared to men. Race and age were not predictive of any outcomes, nor was mTBI.

Discussion

The aims of this study were to examine the association of childhood, non-military adult and combat trauma on current, post-military mental health outcomes of alcohol consumption, PTSD symptom severity, and depression symptoms, as well as examine whether childhood and non-military adult trauma moderate the relationship between combat trauma on these post-military mental health outcomes.

In support of our hypothesis, combat trauma was found to be significantly associated with each of the post-deployment outcomes, consistent with previous literature [risky drinking (Jacobson et al., 2008), PTSD symptoms (Xue et al., 2015), depression symptoms (Hassija et al., 2012)] even after taking into account childhood and non-military adult trauma. The pattern of associations for non-military adult trauma partially supported our hypothesis; while non-military adult trauma was associated with psychiatric outcomes (i.e., PTSD symptoms, depression symptoms) it was not associated with alcohol use. The current study extends the literature to include evidence that adult non-military trauma is associated with depression symptoms, above and beyond combat exposure, suggesting that ongoing stressors may have an independent impact on depression. The association of non-military adult trauma with PTSD is also in line with prior work which found that non-combat interpersonal trauma was associated with PTSD symptoms, and indeed more strongly related to PTSD than combat exposure (Ozer et al., 2003).

Contrary to our expectations, childhood trauma was not associated with any of the outcomes in this sample. This does, however, mirror the literature showing that adverse childhood experiences are not associated with alcohol use when combat trauma is also included (Fritch et al., 2010; Vest et al., 2018). However, the results are inconsistent with other prior research that has found childhood interpersonal trauma to be associated with PTSD symptoms (Cabrera et al., 2007; Fritch et al., 2010; Van Voorhees et al., 2012), depression symptoms (Cabrera et al., 2007), and alcohol misuse (Clarke-Walper et al., 2013) even in the presence of combat trauma. This difference may be due to the simultaneous analysis of outcomes in the present study compared to separate analyses conducted in the extant literature. It is also noted that in the present study, current PTSD symptoms were assessed with regard to traumatic combat experiences, specifically, and not with regard to childhood trauma if it was present. The lack of association among childhood trauma and these outcomes in the presence of combat trauma does, however, align with the suppressor model proposed by Solomon and Flum (1998), which suggests that high combat exposure would overshadow the effects of other factors (i.e., childhood trauma) on psychiatric outcomes. Although further examination of this process is beyond the scope of the present study, given that this finding has been repeated across other studies, and the documented high rates of combat exposure in veterans of the more recent conflicts, future research would benefit from further conceptualization of this phenomenon. Nevertheless, study results highlight how relationships involving different trauma types vary based on outcome, despite the co-occurrence found among depression, alcohol use, and PTSD.

While dose-dependent theory suggests a possible interaction effect such that greater trauma exposure (i.e., participants endorsing both high childhood or non-military adult and high combat traumas) would be most associated with a greater likelihood of negative outcomes, existing work testing the interaction among trauma exposure and psychiatric symptoms has showed contradictory results (i.e., lower childhood trauma was associated with greater symptoms in the presence of high combat trauma; Cabrera et al., 2007; Vest et al., 2018). These prior studies described the possibility of a ceiling effect, characterized by lower reactivity to later trauma in participants endorsing higher levels of childhood trauma or maltreatment. In the present study, none of the interaction results were found to be associated with alcohol consumption, depression symptoms, or PTSD symptoms, inconsistent with the dose-dependent theory, but consistent with prior studies (Fritch et al., 2010). These findings may be viewed in the context of some alternate theories regarding the possibility that a history of childhood maltreatment might impart a “steeling,” or inoculating, effect (i.e., perhaps through improved coping; Stein et al., 2005). Other possible reasons for this lack of association may be due to the nature of the variables used to assess trauma and PTSD symptoms. Results suggest that the total number (i.e., main effect) of trauma events is most important in predicting outcomes, as compared to a synergistic effect, as well as the pervasive nature of combat trauma, in that rather than creating an interdependent association, childhood trauma and civilian trauma do not add to the effect of combat trauma. Other researchers have suggested that the absence of an interaction effect points to the resilience of many service members with a history of childhood traumatic events (Fritch et al., 2010; Stein et al., 2005). It is also important to note that interaction effects may be more relevant for, or present, in clinical, treatment-seeking populations. More work is needed to fully clarify the nature of these interactions.

Individual relationships among the trauma types and outcomes illustrate the value of the assessment of prior traumas within the combat-exposed veteran community. In combat-exposed military samples, combat trauma specifically receives the most attention as a precipitator of PTSD, depression, and alcohol consumption (Dedert et al., 2009; Hassija et al., 2012; Kelley et al., 2013; Wilk et al., 2010). Extant work and present study findings further support the strength of the relationship among combat trauma and these psychiatric outcomes. However, this work and other studies have demonstrated the impact of prior traumas on these outcomes individually as well as when accounting for combat-related traumas (Voorhees et al., 2012), suggesting that assessment of, and treatment for, these post-deployment outcomes should be sure to consider trauma history beyond the combat context. A post hoc analysis examined the association of combined non-military traumas on outcomes of interest with results mirroring the separate childhood and non-military adult analyses. Results further underscore the impact of these prior traumas as a whole on psychiatric (PTSD and depression symptoms) outcomes but less so on alcohol consumption outcomes. These findings also highlight that trauma is a non-specific risk factor and it increases risk for a variety of negative outcomes other than PTSD (e.g., depressive symptoms). The current study also extends the literature by examining commonly co-occurring outcomes (i.e., PTSD, depression, and alcohol use) all in one model and allowing these outcomes to correlate in the analyses.

Limitations and Future Directions

This study should be considered in light of a number of limitations. Given the inclusion/exclusion criteria of the parent study, participants who self-reported that they were currently exhibiting the riskiest forms of our alcohol and depression outcomes in the pre-screening were excluded. While some individuals who were assessed in the study fell above the clinical cut-offs for probable MDD and alcohol abuse or dependence, given the pre-screening exclusion, the sample is limited in regard to clinical levels of depression and AUD. Furthermore, participants were drawn from a non-treatment-seeking community sample; thus, it is unknown if these patterns would extend to individuals who are seeking mental health treatment. Previous literature demonstrates that both treatment-seeking civilians and veterans have higher trauma rates, and patients with co-occurring conditions are generally more subject to relapse, poor prognosis, and more persistent and severe courses of conditions (Jacobson et al., 2008; Merikangas et al., 2003; Swendsen et al., 1998). Therefore, replicating this model in both a treatment-seeking and clinical group can further clarify this co-occurrence. It is noted, however, that distress was evident (i.e., 13.9% above threshold on the BDI) and a large proportion was engaging in problematic alcohol use (17.9% categorized as risky drinkers) in this non-treatment-seeking sample. As such, present findings can inform on sub-threshold presentation and may provide information on pre-development of these diagnoses.

A novel aspect of the current study was that our analyses allowed for the examination of commonly co-occurring outcomes in one model. We note, however, that mTBI is recognized as having important implications in relation to PTSD, depression, and alcohol use outcomes (Corrigan & Cole, 2008; Grossbard et al., 2017; McHugo et al., 2017). Given that the parent study only assessed for mild forms of TBI using a brief screener, we included mTBI as a covariate, but refrained from specific examinations and hypotheses related it its role as a predictor. Notably, although mTBI status had a small, significant correlation with both PTSD and depression symptoms, as would be expected, it was not significantly associated with any of the outcomes in the models. Further research utilizing more appropriate screeners and measures of post-concussive symptoms will be important for examining outcomes associated with the comorbidity among mTBI, PTSD symptoms, depression symptoms, and alcohol consumption.

It was also noted previously that current PTSD symptoms were assessed in specific relation to the most traumatic combat-related experience, whether or not other trauma exposures were present, while the alcohol measures and depression measures were assessed broadly and are not necessarily linked to traumatic events. Future examination of PTSD through other traumatic experiences unrelated to combat would be useful.

Additionally, while this sample is representative of the larger military population and the VA census, limits to generalizability also exist given the demographics of the sample, which did not allow for specific examination of racial/ethnic differences. Further, the findings with regard to sex (i.e., association with PTSD symptoms, no association with depression symptoms or alcohol use) should be interpreted with caution given the small number of females in the study (11.3%, n = 34). Given the relevance of examining racial/ethnic and gender-related differences in this field, inclusion of a more diverse sample with regards to gender and race is recommended for future studies.

Another limitation relates to our measures of non-military adult and childhood traumatic events. Given that the DRRI A is not designed as a comprehensive trauma history measure, we strategically chose to include specific items that encompassed both childhood traumatic events and non-military adult traumatic events, which led to the inclusion of fewer items. Additionally, because the DRRI subscale assesses for pre-deployment events that may or may not have been pre-military if the veteran has been deployed on multiple occasions, conclusions are limited with regard to temporality; however, findings still inform upon the association of non-military as compared to combat-related events on outcomes. Future studies would benefit from the utilization of more targeted measures for childhood and non-military adult trauma groups as well as examination of additional substances, alternative alcohol use measures, and physical health outcomes (e.g., chronic pain).

Conclusions

Overall, our results underscore the importance of assessing multiple trauma types and considering trauma as a non-specific risk factor, as different trauma types differentially predict various psychiatric outcomes other than PTSD. Further, while combat trauma is an especially pervasive risk factor, results of the present study maintain the importance of examining multiple trauma types other than solely combat trauma in the veteran population. The current study extends the literature by examining commonly co-occurring outcomes in one model, allowing for correlation of these outcomes in the analyses. Future research examining these associations in a clinical, treatment seeking, and diverse sample with regard to gender and race/ethnicity will help improve generalizability and further clarify these associations.

Footnotes

Authors’ Note

Brianna A. George is now affiliated with Department of Psychology, Virginia Polytechnic Institute and State University.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The main study was funded by the National Institute on Alcohol Abuse and Alcoholism (NIAAA) under grants R01 AA020179 and K02 AA023239 (PI: Amstadter). Support for writing of this manuscript came from National Institutes of Health grant R25 GM0896 (B.G.), NIAAA grant K01 AA025692 (C.S.), and NIAAA grant F31 AA025820 (S.H.).

ORCID iDs

Brianna A. George

Kaitlin E. Bountress

Author Biographies

Brianna A. George, BS, is a doctoral student in Clinical Science at Virginia Polytechnic Institute and State University. Brianna seeks to (a) examine how minority-related stressors and discrimination impact post-trauma trajectories of marginalized populations and (b) understand mechanisms by which interpersonal trauma is linked to psychiatric outcomes. Ultimately, Brianna aims to disseminate research that promotes and prioritizes the awareness of cultural differences.

Kaitlin E. Bountress, PhD, is an assistant professor in the Virginia Institute for Psychiatric and Behavioral Genetics at Virginia Commonwealth University. Her research focuses on genetic and environmental influences on alcohol use outcomes, PTSD, and their comorbidity. She is also interested in using longitudinal modeling approaches (e.g., structural equation model, latent growth curve modeling, mediation) to better understand the processes and potential mechanisms underlying this comorbidity.

Ruth C. Brown, PhD, is an assistant professor of Psychiatry in the Virginia Institute for Psychiatric and Behavioral Genetics at Virginia Commonwealth University. Her program of research focuses on improving the measurement and treatment of trauma and related psychiatric disorders in people with developmental disabilities.

Sage E. Hawn, MS, is on track to receive her PhD in Clinical Psychology from Virginia Commonwealth University, after which time she will begin her T32 postdoctoral fellowship at the National Center for PTSD in Boston, MA. Her research interests lie at the intersection of biological (e.g., genetic, neuroendocrine) and psychosocial factors that influence posttraumatic stress disorder (PTSD) and other trauma-related pathologies (e.g., substance use disorder).

Emily A. Brown Weida, DrPH(c), MSW, is a doctoral candidate in Health Management and Policy at Drexel University’s Dornsife School of Public Health. Her research focuses on the impact of trauma and adversity on the health of individuals, families, and communities, as well as the creation, promotion, and evaluation of trauma-informed interventions and policies.

Scott D. McDonald, PhD, is SCI Neuropsychologist at the McGuire VA Medical Center and affiliate Assistant Professor in Virginia Commonwealth University’s Departments of Psychology and Physical Medicine & Rehabilitation. Dr. McDonald’s research focuses on understanding adjustment and long-term psychosocial sequelae after trauma and acquired physical disability among military Veterans.

Treven Pickett, PsyD, ABPP, is the Department Chief, Research, for the National Intrepid Center of Excellence (NICoE) Directorate, Walter Reed National Military Medical Center (WRNMMC), Bethesda, Maryland. In this role, he oversees an advanced neurological and behavioral science research program. His research background and interests are in traumatic brain injury (TBI) and associated psychological health conditions.

Carla Kmett Danielson, PhD, is a professor in the Department of Psychiatry & Behavioral Sciences at MUSC. Her research focuses on promoting resiliency among young people who have experienced adversity through translational, lab-based studies that unveil mechanisms linking traumatic experiences and mental health outcomes and through clinical trials of treatment and prevention interventions that target such mechanisms to improve outcomes.

Christina M. Sheerin, PhD, is an assistant professor in the Virginia Institute for Psychiatric and Behavioral Genetics at Virginia Commonwealth University. Her research focuses on the characterization of biologic, genetic, and psychosocial underpinnings of the effects of trauma, primarily PTSD, alcohol use disorder (AUD), and their comorbidity.

Ananda B. Amstadter, PhD, is an associate professor of Psychiatry, Psychology, and Human and Molecular Genetics in the Virginia Institute for Psychiatric and Behavioral Genetics at Virginia Commonwealth University. Her program of research is aimed at understanding the genetic and environmental etiology of traumatic stress-related disorders and their comorbidity.

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