Background
In recent years, concerns about the high rates of traumatic brain injury (TBI) experienced by veterans who served in Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF) have led researchers, policy makers, and the media to pay considerable attention to the identification and treatment of TBI and its comorbidities. The prevalence of TBI is between 12% and 20% for OEF/OIF veterans, with most cases being mild in severity (
Hendricks et al., 2011, FebruaryHendricks, A., Amara, J., Baker, E., Charns, M., Gardner, J. A., Iverson, K. M., et al. (2011, February). Screening for mild traumatic brain injury in OEF-OIF deployed military: An empirical assessment of the VA Experience. Research paper presented at the National HSR&D Conference, Washington, DC.
,
Hoge et al., 2008- Hoge C.W.
- McGurk D.
- Thomas J.L.
- Cox A.L.
- Engel C.C.
- Castro C.A.
Mild traumatic brain injury in U.S. soldiers returning from Iraq.
,
Schneiderman et al., 2008- Schneiderman A.I.
- Braver E.R.
- Kang H.K.
Understanding sequelae of injury mechanisms and mild traumatic brain injury incurred during the conflicts of Iraq and Afghanistan: Persistent postconcussive symptoms and posttraumatic stress disorder.
,
Tanielian and Jaycox, 2008Invisible wounds of war: Psychological and cognitive injuries, their consequences, and services to assist recovery.
). Although women are serving in the military at higher rates than ever before and have expanded their occupational roles during deployments (
Murdoch et al., 2006- Murdoch M.
- Bradley A.
- Mather S.H.
- Klein R.E.
- Turner C.L.
- Yano E.M.
Women and war: What physicians should know.
,
Street et al., 2009- Street A.E.
- Vogt D.
- Dutra L.
A new generation of women Veterans: Stressors faced by women deployed to Iraq and Afghanistan.
), the impact of deployment-related TBI on women’s health is largely unknown. However, 12.7% of the Department of Veterans Affairs (VA) OEF/OIF women patients screen positive for TBI or report a prior TBI diagnosis (
Hendricks et al., 2011, FebruaryHendricks, A., Amara, J., Baker, E., Charns, M., Gardner, J. A., Iverson, K. M., et al. (2011, February). Screening for mild traumatic brain injury in OEF-OIF deployed military: An empirical assessment of the VA Experience. Research paper presented at the National HSR&D Conference, Washington, DC.
).
Among veterans, psychiatric and neurobehavioral disturbances often co-occur with TBI, which can complicate recovery and add to the challenge of coordination of care (
Sayer et al., 2009- Sayer N.A.
- Rettmann N.A.
- Carlson K.F.
- Bernardy N.
- Sigford B.J.
- Hamblen J.L.
- et al.
Veterans with history of mild traumatic brain injury and posttraumatic stress disorder: Challenges from provider perspective.
). For example, a recent investigation of VA patients with TBI documented in their medical charts found that nearly two thirds (63.9%) also had a diagnosis of posttraumatic stress disorder (PTSD), and large pluralities had diagnoses of depression (46.3%), non-PTSD anxiety disorders (35.6%), and substance use disorders (26.2%) documented at least once in a VA mental health, primary care, or rehabilitation clinic since separation from the military (
Carlson et al., 2010- Carlson K.F.
- Nelson D.
- Orazem R.J.
- Nugent S.
- Cifu D.X.
- Sayer N.A.
Psychiatric diagnoses among Iraq and Afghanistan war veterans screened for deployment-related traumatic brain injury.
). Despite the potential impact of these conditions, there exists no published investigation of gender differences in the psychiatric and neurobehavioral comorbidities of TBI among OEF/OIF veterans.
Such research is needed in veterans because a growing literature suggests that women tend to fare worse than men in terms of psychiatric and neurobehavioral symptoms after TBI (
Colvin et al., 2009- Colvin A.C.
- Mullen J.
- Lovell M.R.
- West R.V.
- Collins M.W.
- Groh M.
The role of concussive history and gender in recovery from soccer-related concussion.
,
Fann et al., 2004- Fann J.R.
- Burington B.E.
- Leonetti A.
- Jaffe K.
- Katon W.J.
- Thompson R.S.
Psychiatric illness following traumatic brain injury in an adult health maintenance organization population.
,
Jensen and Nielsen, 1990The influence of sex and pre-traumatic headache on the incidence and severity of headache after head injury.
,
McCarthy et al., 2006- McCarthy M.L.
- Dickmen S.S.
- Langlois J.A.
- Selassie A.W.
- Gu J.K.
- Horner M.D.
Self-reported psychosocial health among adults with traumatic brain injury.
). For instance, among a health maintenance organization sample with no history of psychiatric illness,
Fann et al., 2004- Fann J.R.
- Burington B.E.
- Leonetti A.
- Jaffe K.
- Katon W.J.
- Thompson R.S.
Psychiatric illness following traumatic brain injury in an adult health maintenance organization population.
found that women were at greater risk, relative to men, for developing psychiatric problems subsequent to TBI. It is unclear, however, whether these findings would generalize to OEF/OIF VA patients given the large age range of the sample (15–95 years). A meta-analysis of eight studies concluded that TBI neurobehavioral outcomes were worse in women than in men for 85% of 20 measured outcomes, including memory, headaches, dizziness, fatigue, irritability, anxiety, and depression (
Farace and Alves, 2000Do women fare worse? A metaanalysis of gender differences in outcome after traumatic brain injury.
). Moreover, the sports concussion literature suggests there may be gender differences in postconcussive symptom reporting among athletes (
Dick, 2009Is there a gender difference in concussion incidence and outcomes?.
). For example, in a sample of soccer players with a history of concussion, women reported a significantly higher number of discrete neurobehavioral symptoms than their male counterparts (
Colvin et al., 2009- Colvin A.C.
- Mullen J.
- Lovell M.R.
- West R.V.
- Collins M.W.
- Groh M.
The role of concussive history and gender in recovery from soccer-related concussion.
).
Given the growing number of women veterans seeking care within the VA (
Yano et al., 2010- Yano E.M.
- Hayes P.
- Wright S.
- Schnurr P.P.
- Lipson L.
- Bean-Mayberry B.
- et al.
Integration of women Veterans into VA quality enhancement research efforts: What researchers need to know.
), as well as evidence of gender differences in psychiatric and neurobehavioral comorbidities of TBI in non-veteran samples, it is important to determine whether gender differences exist among OEF/OIF VA patients with deployment-related TBI. This study examined gender differences in the presence of psychiatric diagnoses and neurobehavioral symptom severity among the population of OEF/OIF VA patients judged to have deployment-related TBI. Consistent with the research described, we hypothesized that women veterans would be more likely than their male counterparts to experience more psychiatric diagnoses as well as more severe neurobehavioral symptoms.
Results
As noted, analyses were focused on the 12,605 OEF/OIF veterans who were evaluated as having deployment-related TBI during the observation period. Patient demographic characteristics, percentages with psychiatric diagnoses and severe/very severe neurobehavioral symptoms are presented separately for women (
n = 654) and men (
n = 11,951) in
Table 1. The mean scores for the neurobehavioral symptoms domains are as follows: Affective (women,
M = 2.53,
SD = 0.96; men,
M = 2.43,
SD = 0.96), somatosensory (women,
M = 1.80,
SD = 0.79; men,
M = 1.55,
SD = 0.76), cognitive (women,
M = 2.29,
SD = 1.05; men,:
M = 2.16,
SD = 1.04), and vestibular (women,
M = 1.54,
SD = 0.91; men,
M = 1.28,
SD = 0.86).
Univariate relationships for women compared with men on psychiatric diagnoses and severe/very severe neurobehavioral symptoms revealed gender differences in both types of outcomes (see
Table 2 for unadjusted relationship values). For psychiatric diagnoses, women were .70 times less likely than men to have a PTSD diagnosis. Women were also significantly less likely than men to have substance abuse diagnoses as well as only one psychiatric diagnosis. In contrast, relative to men, women were nearly 2 times more likely to have a depression diagnosis, 1.3 times more likely to have a non-PTSD anxiety disorder, and over 1.5 times more likely to have PTSD with comorbid depression. In terms of neurobehavioral symptoms, women were significantly more likely than men to report severe somatosensory, cognitive, and vestibular symptoms, with odds ratios ranging from 1.3 to 1.9.
Table 2Psychiatric Diagnoses and Severe/Very Severe Neurobehavioral Symptoms for Women Relative to Men
Abbreviations: CI, confidence interval; OR, odds ratio.
Note. Reference group is males.
All of the analyses that adjust for blast have also been adjusted for etiology (blast, bullet, fall, vehicle, other blunt trauma), marital status, education, employment, rank, service, age, and years of service. The four neurobehavioral symptom domains were obtained from a factor analysis of the Neurobehavioral Symptom Inventory-22 (described under Methods). Neurobehavioral symptom severity scores were dichotomized into ‘none/mild/moderate’ (mean scale score < 3) or ‘severe/very severe’ (mean scale score ≥ 3) groups.
Some of the gender difference findings were no longer significant after accounting for participants’ exposure to blasts while on deployment (see
Table 2 for blast-adjusted relationship values). Specifically, women were no longer less likely than men to have a PTSD diagnosis, drug-related diagnoses, or have only one psychiatric diagnosis after controlling for blast exposure. Additionally, women were no more likely than men to have a diagnosis of a non-PTSD anxiety disorder after controlling for blast exposure. In contrast, women were more likely to report severe/very severe symptoms on all four neurobehavioral symptom domains.
Discussion
To our knowledge, this is the first study analyzing gender differences in psychiatric conditions and neurobehavioral symptom severity among OEF/OIF veterans with deployment-related TBI who are using VA care. As expected, and consistent with previous research in the general population (e.g.,
Fann et al., 2004- Fann J.R.
- Burington B.E.
- Leonetti A.
- Jaffe K.
- Katon W.J.
- Thompson R.S.
Psychiatric illness following traumatic brain injury in an adult health maintenance organization population.
) and with athletes (e.g.,
Colvin et al., 2009- Colvin A.C.
- Mullen J.
- Lovell M.R.
- West R.V.
- Collins M.W.
- Groh M.
The role of concussive history and gender in recovery from soccer-related concussion.
), we documented gender differences in the unadjusted odds of psychiatric diagnoses and neurobehavioral outcomes among VA patients with deployment-related TBI. Specifically, we found that compared with men, women were much more likely to have a depression diagnosis. Women were also more likely than men to be diagnosed with a non-PTSD anxiety disorder as well as PTSD with comorbid depression. In contrast, women were less likely than men to be diagnosed with PTSD only or with substance use disorders. In terms of neurobehavioral symptoms, women were more likely to report severe or very severe somatosensory, cognitive, and vestibular symptoms. Some of these gender differences (i.e., PTSD differences, non-PTSD anxiety disorders, and drug-related disorders), were not maintained after adjusting for blast exposure.
The large gender difference in depression diagnoses among patients judged to have deployment-related TBI (49% vs. 33%, a 16-point difference) is more than twice that observed in the general population of OEF/OIF VA patients (23% vs. 17%, a 6-point difference;
Maguen et al., 2010- Maguen S.
- Ren L.
- Bosch J.O.
- Marmar C.R.
- Seal K.H.
Gender differences in mental health diagnoses among Iraq and Afghanistan Veterans enrolled in Veterans Affairs health care.
). The high percentages of depression reported by women in this study is notable because greater functional disability, poorer recovery, and higher rates of suicide attempts are all associated with depression after TBI (
Fann et al., 1995- Fann J.R.
- Katon W.J.
- Uomoto J.M.
- Esselman P.C.
Psychiatric disorders and functional disability in outpatients with traumatic brain injuries.
;
Mooney et al., 2005- Mooney G.
- Speed J.
- Sheppard S.
Factors related to recovery after mild traumatic brain injury.
;
Rapoport et al., 2003- Rapoport M.J.
- McCullagh S.
- Streiner D.
- Feinstein A.
The clinical significance of major depression following traumatic brain injury.
,
Silver et al., 2001- Silver J.M.
- Kramer R.
- Greenwald S.
- Weissman M.
The association between head injuries and psychiatric disorders: Findings from the New Haven NIMH Epidemiologic Catchment Area Study.
). Consistent with the VA’s clinical practice guidelines for the management of mild TBI, the current findings highlight the critical need for early detection and aggressive treatment of depression among women veterans with deployment-related TBI (
).
Regarding other gender differences in psychiatric diagnoses, consistent with the general population of OEF/OIF VA patients (
Maguen et al., 2010- Maguen S.
- Ren L.
- Bosch J.O.
- Marmar C.R.
- Seal K.H.
Gender differences in mental health diagnoses among Iraq and Afghanistan Veterans enrolled in Veterans Affairs health care.
), univariate analyses demonstrated women were more likely than men to have a non-PTSD anxiety disorder (20.3% vs. 16.3%) and less likely than men to have alcohol (16.2% vs. 27.0%) and drug-related disorders (4.9% vs. 8.2%). However, the magnitude of these gender differences are more pronounced in the current sample relative to the general population of OEF/OIF VA patients (
Maguen et al., 2010- Maguen S.
- Ren L.
- Bosch J.O.
- Marmar C.R.
- Seal K.H.
Gender differences in mental health diagnoses among Iraq and Afghanistan Veterans enrolled in Veterans Affairs health care.
). It is noteworthy that the gender effect for non-PTSD anxiety disorders and drug-related disorders was not maintained once controlling for blast exposure. Despite these important gender differences, women and men did not differ significantly in terms of adjustment disorders or stress reactions. Additionally, contrary to our hypotheses, women were no more likely than men to have multiple psychiatric diagnoses, with approximately half of veterans of either gender (53.2% of women, 48.7% of men) being diagnosed with two or more psychiatric conditions.
The univariate associations between gender and PTSD (59.6% of the women compared with 67.8% of the men) was not maintained after controlling for blast exposure. This finding suggests that men’s greater likelihood of blast exposure (
Table 1), possibly from greater combat exposure (
Hoge et al., 2007- Hoge C.W.
- Clark J.C.
- Castro C.A.
Commentary: Women in combat and the risk of post-traumatic stress disorder and depression.
), may account for their higher likelihood of having a PTSD diagnosis. This adjusted finding is consistent with previous research demonstrating a lack of gender differences in terms of PTSD among veterans, controlling for specific deployment-related stressors (
). Additionally, approximately 38% of women had diagnoses of PTSD with comorbid depression compared with 28% of the men. Thus, PTSD with comorbid depression is a prominent women’s health issue among VA patients judged to have deployment-related TBI.
Findings did support our hypothesis that women would report more severe neurobehavioral symptoms. Specifically, women were significantly more likely to report ‘severe’ or ‘very severe’ symptoms on three of the four neurobehavioral symptom domains in the univariate analyses (the exception being affective symptoms) and all four of the symptom domains in the multivariate analyses adjusting for blast exposure. These findings match results from studies examining gender differences in neurobehavioral symptoms among athletes with TBI (
Colvin et al., 2009- Colvin A.C.
- Mullen J.
- Lovell M.R.
- West R.V.
- Collins M.W.
- Groh M.
The role of concussive history and gender in recovery from soccer-related concussion.
,
Dick, 2009Is there a gender difference in concussion incidence and outcomes?.
). Although the mechanisms associated with these worse outcomes remain unknown, these findings suggest that in addition to the identification and treatment of psychiatric conditions, it is critical that clinicians attend to the affective, somatosensory, cognitive, and vestibular symptoms experienced by women veterans with deployment-related TBI. Recognition of these symptoms in women veterans enables clinicians to better tailor treatment approaches for women’s specific health care needs. For example, a woman who reports severe cognitive symptoms may benefit from cognitive remediation (
). Likewise, increased detection of neurobehavioral symptoms among women veterans may lead to improvements in coordination of care for women in mental health, as well as physical and occupational rehabilitation settings. Consistent with the literature pertaining to VA care for women (
Yano et al., 2003- Yano E.M.
- Washington D.L.
- Goldzweig C.
- Caffrey C.
- Turner C.
The organization and delivery of women’s health care in Department of Veterans Affairs Medical Center.
), the current findings also suggest the importance of interdisciplinary treatment of women VA patients with mild TBI.
In light of the high rates of psychiatric and neurobehavioral comorbidities observed in this study, the current findings can help guide clinicians’ use of specific therapy options for their female patients with TBI and these co-occurring conditions, particularly PTSD and depression. In particular, cognitive–behavioral therapies for PTSD are very effective in ameliorating veterans’ symptoms of both PTSD and depression (
), and at this time there is no evidence that these treatments need to be significantly altered for patients with mild TBI. On the contrary, there is preliminary evidence that Cognitive Processing Therapy (
Resick et al., 2007- Resick P.A.
- Monson C.M.
- Chard K.M.
Cognitive processing therapy: Veteran/military version: Therapist’s manual.
), an empirically supported treatment for PTSD that is widely available in the VA, is effective for reducing PTSD and depression symptoms among veterans with TBI with little alteration to the protocol (
Chard et al., In pressChard, K. M., Schumm, J., McIlvain, S., Bailey, G., & Parkinson, R. (In press). Exploring the efficacy of a CPT-Cognitive Only (CPT-C) focused residential treatment program for veterans with PTSD and traumatic brain injury. Journal of Traumatic Stress.
). Yet, some clinicians understandably worry that existing cognitive–behavioral therapies, such as Cognitive Processing Therapy, are too reliant on memory and thus may be inappropriate for patients with TBI (
Sayer et al., 2009- Sayer N.A.
- Rettmann N.A.
- Carlson K.F.
- Bernardy N.
- Sigford B.J.
- Hamblen J.L.
- et al.
Veterans with history of mild traumatic brain injury and posttraumatic stress disorder: Challenges from provider perspective.
). Clinicians should keep in mind that many evidence-based therapies, such as Cognitive Processing Therapy, can be altered to meet the needs of individual patients with TBI (e.g., longer or shorter sessions, greater repetition of materials, engagement of family members to promote treatment adherence) while still maintaining fidelity to the treatment model.
Several limitations of this study should be noted, because they point to avenues for future research. Although the determination of TBI was established via structured clinical interviews and is thus an asset of the study, the VA Comprehensive TBI Evaluation has not undergone an evaluation of sensitivity and specificity in terms of accuracy of determining TBI. Similarly, the psychiatric diagnoses were derived from ICD-9 codes. Although this method is common in research examining psychiatric conditions among patients of large health care systems (
Carlson et al., 2010- Carlson K.F.
- Nelson D.
- Orazem R.J.
- Nugent S.
- Cifu D.X.
- Sayer N.A.
Psychiatric diagnoses among Iraq and Afghanistan war veterans screened for deployment-related traumatic brain injury.
,
Fann et al., 2004- Fann J.R.
- Burington B.E.
- Leonetti A.
- Jaffe K.
- Katon W.J.
- Thompson R.S.
Psychiatric illness following traumatic brain injury in an adult health maintenance organization population.
,
Kimerling et al., 2010- Kimerling R.
- Street A.E.
- Pavao J.
- Smith M.W.
- Cronkite R.C.
- Holmes T.H.
- Frayne S.M.
Military-related sexual trauma among Veterans Health Administration patients returning from Afghanistan and Iraq.
), these diagnoses can be subject to false-positive and false-negative cases. Thus, the current findings may not reflect the true rate of psychiatric disorders among this population and findings should be replicated using validated assessments of psychiatric conditions and more rigorous neurobehavioral symptom measures. Another limitation is that this study measured cognitive symptoms via a self-report measure. Additional research is needed to replicate the current findings with cognitive performance measures because subjective cognitive complaints have been found be related to mood, such as depressive symptoms (
Marino et al., 2009- Marino S.E.
- Meador K.J.
- Loring D.W.
- Okun M.S.
- Fernandez H.H.
- Fessler A.J.
- et al.
Subjective perception of cognition is related to mood not performance.
).
Another study limitation is the cross-sectional nature of the research design. As such, a causal relationship cannot be inferred between deployment-related TBI and the psychiatric conditions and neurobehavioral symptoms. Future longitudinal research should evaluate the nature of these relationships, as well as elucidate mediating and moderating variables that may help to explain gender differences in health outcomes among veterans with deployment-related TBI. In addition to blast exposure, researchers should investigate a broader range of deployment-related stressors that may contribute to gender differences (and lack thereof), including sexual trauma and combat severity. Given that only half of the veterans who screened positive for TBI underwent a Comprehensive TBI Evaluation, it is possible that the current sample is an underestimate of the true rate of OEF/OIF veterans with deployment-related TBI. Research is needed to elucidate patient-, provider-, and facility-level factors that impact the likelihood a patient will go on to receive a Comprehensive TBI Evaluation after a positive TBI screen. For example, patient-level factors, such as mental health diagnoses or cognitive disturbances, may impact a veteran’s willingness or ability to arrange and attend such an appointment. There may also be differences in how clinicians provide feedback about a positive TBI screen and referrals for the evaluation that may influence variation in rates of receiving a Comprehensive TBI Evaluation. Additionally, it is important to remember that the current findings based on VA patients may not generalize to patients in other health care settings. Future inquiries should include samples of veterans who do not utilize VA health care to determine if the pattern of findings presented herein is maintained. Future research is also needed to further identify and treat symptoms (e.g., pain) that are of high clinical relevance in female patients judged to have mild TBI. Finally, it is essential to monitor whether evidence-based treatments for conditions such as PTSD and depression lead to improvements in neurobehavioral symptom severity for women VA patients judged to have deployment-related TBI.
In summary, there are gender differences in the comorbidities of deployment-related TBI among OEF/OIF VA patients. It is important to continue to understand these differences, as well as similarities, to inform practices to provide the highest quality care possible for women veterans.
Biography
Dr. Iverson is a Clinical Research Psychologist at the National Center for PTSD, Women’s Health Sciences Division and an Investigator at the Center for Organization, Leadership and Management Research, VA Boston Healthcare System. She specializes in women’s traumatic stress research.
Ann M. Hendricks, PhD, directs Health Care Financing & Economics at VA Boston Healthcare System and is an associate professor at Boston University’s School of Public Health. Her research focuses on VA programs for mild traumatic brain injury and end-of-life care.
Dr. Kimerling is a Clinical Psychologist at the National Center for PTSD, Dissemination and Training Division, and an Investigator at the Center for Health Care Evaluation, VA Palo Alto Health Care System. She specializes in sexual trauma research.
Dr. Krengel is a Neuropsychologist at the VA Boston Healthcare System and Clinical Assistant Professor at Boston University’s School of Medicine. She is the PI of a Department of Defense funded study on Gulf-War I Veterans’ Health.
Dr. Meterko is an Investigator at the VA Center for Organization, Leadership and Management Research, where he also leads the Methodology and Survey Unit. He is also Research Associate Professor, Health Policy & Management, Boston University School of Public Health.
Kelly Stolzmann, MS, is a research analyst for the VA Boston Healthcare System at the Center for Organization, Leadership, and Management Research (COLMR).
Dr. Baker is a Biostatistician and Senior Investigator at Center for Organization, Leadership and Management Research (COLMR), VA HSR&D Center of Excellence, VA Boston Health Care System, with over 35 years experience dealing with large scale studies employing multivariate analyses.
Dr. Pogoda is a Research Health Scientist and Investigator at the VA Boston Healthcare System’s Center for Organization, Leadership and Management Research. She is also a Research Assistant Professor at the Boston University School of Public Health.
Dr. Vasterling serves as Chief of Psychology at VA Boston Healthcare System and Professor of Psychiatry at Boston University School of Medicine. She is an affiliate investigator in the Behavioral Sciences Division of the VA National Center for PTSD.
Dr. Lew is Professor of Physical Medicine and Rehabilitation at Virginia Commonwealth University (VCU), and Consultant for the Defense and Veterans Brain Injury Center (DVBIC).
Article info
Publication history
Accepted:
April 20,
2011
Received in revised form:
April 19,
2011
Received:
November 25,
2010
Footnotes
A portion of Dr. Iverson’s contribution to this manuscript was supported by a training grant from the National Institute of Mental Health (T32MH019836) awarded to Terence M. Keane.
Copyright
Published by Elsevier Inc.