Posttraumatic stress disorder and traumatic brain Injury: Sex differences in veterans

Psychiatric Disorders Are Common Among Older US Veterans Prior to Traumatic Brain Injury

OBJECTIVE

To estimate the impact of traumatic brain injury (TBI) on prevalence of posttraumatic stress disorder (PTSD), depression, and alcohol and substance use disorders.

SETTING

A random sample of Veteran's Health Administration data.

PARTICIPANTS

A total of 14 116 veterans aged ≥55 with incident late-life TBI between October 1, 1999, and September 31, 2021, were matched 1:3 on age and TBI date to 42 678 veterans without TBI.

DESIGN

Retrospective cohort study.

MAIN MEASURES

PTSD, depression, and alcohol and substance use disorders were identified using diagnostic codes. Participants were censored after the first diagnosis during the year before and the year after the TBI or matched date. Prevalence rates of PTSD, depression, alcohol, and substance use disorders were compared before and after incident TBI or matched date using Poisson regression.

RESULTS

Pre-TBI prevalence rates of disorders were higher among those with TBI relative to those without TBI. Pre-TBI PTSD prevalence rates (per 1000 person-years) were 126.3 (95% CI, 120.2-132.4) compared to 21.5 (95% CI, 20.1-22.9) in the non-TBI cohort. In adjusted models, TBI was not associated with an increase in the prevalence of any of the studied disorders.

CONCLUSIONS

Prevalence rates of depression, PTSD, and alcohol and substance use disorders were 5 to 10 times higher among older veterans before incident TBI. We did not observe an increase in the prevalence of these disorders after incident TBI. Older veterans with these disorders may be at increased risk for TBI.

Sex Differences in Postinjury Health Profiles Among U.S. Military Personnel Following Deployment-Related Concussion

Background: Women in the U.S. military are now authorized to serve in direct combat occupations. This may increase their risk of combat injuries, such as concussion, in future conflicts. Knowledge of sex differences in health profiles after concussion is paramount for military medical planning efforts. The purpose of this study was to assess sex-related differences in health profiles among U.S. military personnel following deployment-related concussion. Materials and Methods: We conducted a retrospective study of service members who sustained a concussion during combat deployment between 2004 and 2013. Postinjury diagnoses were abstracted from outpatient encounters in electronic health records for 24 months after concussion. We used hierarchical clustering to identify clusters, termed "health profiles," and logistic regression to determine whether sex predicted membership in the health profiles. Results: The study sample included 346 women and 4536 men with deployment-related concussion. Five postinjury health profiles were identified and classified as no morbidity, back pain, tinnitus/memory loss, posttraumatic stress disorder/postconcussion syndrome, and multimorbidity. Women relative to men had higher odds of membership in the back pain (odds ratio [OR] = 1.32; 95% confidence interval [CI] = 1.05-1.67) and multimorbidity profiles (OR = 1.44; 95% CI = 1.03-2.00) and lower odds than men in the tinnitus/memory loss profile (OR = 0.62; 95% CI = 0.42-0.91). Conclusions: Postinjury health profiles among U.S. service members differ by sex following deployment-related concussion, particularly with a higher burden of multimorbidity among women than men, which may require interdisciplinary care. Women also had higher odds of membership in the back pain profile and lower odds in the tinnitus/memory loss profile than men. To prepare for future military operations where women may have greater exposure to combat, continued research elucidating health-related sex differences after deployment-related concussion is imperative.

Gender differences in disorders comorbid with posttraumatic stress disorder among U.S. Sailors and Marines

Psychological comorbidity, the co-occurrence of mental health disorders, is more often the rule than the exception among individuals with posttraumatic stress disorder (PTSD). Research shows that prevalence estimates for specific psychological disorders differ by gender; however, little is known about whether these patterns persist in the presence of a comorbid PTSD diagnosis. This study examined gender differences in prevalence estimates for conditions comorbid with PTSD using medical records for 523,626 active duty U.S. Sailors and Marines who entered the military over an 8-year period. Using chi-square tests of independence, we detected statistically significant gender differences for specific comorbid conditions in the subsample of 9,447 service members with a PTSD diagnosis. Women were more likely than men to have PTSD with comorbid adjustment, OR = 1.35; depressive, OR = 1.71; and generalized anxiety or other anxiety disorders, OR = 1.16, with the largest effects for eating, OR = 12.60, and personality disorders, OR = 2.97. In contrast, women were less likely than men to have a diagnosis of PTSD with comorbid alcohol use, OR = 0.69, and drug use disorders, OR = 0.72, with the largest effects for insomnia, OR = 0.42, and traumatic brain injury, OR = 0.17. No significant gender differences emerged for comorbid bipolar, obsessive-compulsive, panic/phobic, psychotic, or somatoform/dissociative disorders, ps = .029-.314. The results show gender differences in conditions comorbid with PTSD generally align with internalizing and externalizing dimensions. Differences in comorbidities with PTSD between women and men could have implications for treatment development and delivery.

Posttraumatic stress disorder and relationship functioning: Examining gender differences in treatment-seeking veteran couples

Posttraumatic stress disorder (PTSD) symptoms are robustly associated with intimate relationship dysfunction among veterans, but most existing research has focused on male veterans and their female partners. Links between PTSD and relationship functioning may differ between female-veteran couples and male-veteran couples. The current study used actor-partner interdependence models (APIMs) to test the associations between PTSD symptoms (i.e., veteran self-report or significant others' collateral-report) and each partner's reports of six domains of relationship functioning, as well as whether these links were moderated by the gender composition of the couple. Data were from 197 mixed-gender couples (N = 394 individuals) who completed baseline assessments for a larger randomized controlled trial of a couple-based PTSD treatment. Significant others' collateral PTSD reports were associated with their own ratings of relationship satisfaction, negotiation, psychological aggression, sexual pleasure, and sexual desire frequency, |β|s = .19-.67, and with veterans' ratings of negotiation and sexual desire frequency, |β|s = .20-.48. In contrast, veterans' self-reported PTSD symptoms were only associated with their own ratings of psychological aggression, β = .16. Gender moderated the associations between significant others' collateral PTSD reports and five of the six outcome variables; findings from exploratory subgroup analyses suggested links between reported PTSD symptoms and relationship functioning were generally more maladaptive for male-veteran couples, whereas female veterans showed more neutral or even helpful impacts of higher partner-perceived PTSD symptoms. These findings have implications for clinicians treating relational impacts of PTSD and emphasize the need for further research with female-veteran couples.

Incidence of New Neuropsychiatric Disorder Diagnoses Following Traumatic Brain Injury

BACKGROUND

Neuropsychiatric disturbances (NPDs) are common following traumatic brain injury (TBI) and associated with poor recovery. Prior estimates of NPD following TBI failed to account for preexisting NPDs or potential confounding.

METHODS

We estimated the risk of anxiety, posttraumatic stress disorder (PTSD), bipolar disorder, and alcohol and substance dependence disorder diagnoses associated with TBI using administrative claims data from a large insurer in the United States, 2008-2014. We calculated rates of new NPD diagnoses during the 12 months before and 24 months after TBI and estimated the risk of NPD following TBI using a difference-in-difference approach and adjusting for confounders.

RESULTS

Before the TBI occurred, rates of NPD diagnoses were more than double in the TBI cohort (n = 207 354) relative to the no-TBI cohort (n = 414 708). TBI was associated with an increased risk of anxiety (rate ratio [RtR] = 1.08; 95% confidence interval [CI], 1.05-1.12) and PTSD (RtR = 1.41; 95% CI, 1.24-1.60) diagnoses. Rates of alcohol (RtR = 0.32; 95% CI, 0.30-0.34) and substance use disorder (RtR = 0.57; 95% CI, 0.55-0.59) diagnoses decreased following TBI.

CONCLUSIONS

In this large national study, rates of NPD were much higher among individuals with TBI than those in a non-TBI cohort, even before the TBI took place. TBI was associated with an increased risk of anxiety and PTSD diagnoses. Results from this study also suggest that individuals who sustain TBI have increased contact with the healthcare system during the months prior to injury, providing a window for intervention, especially for individuals diagnosed with alcohol dependence disorder.

Traumatic Brain Injury and Alcohol Drinking Alter Basolateral Amygdala Endocannabinoids in Female Rats

Traumatic brain injury (TBI) affects approximately 3 million Americans yearly and increases vulnerability to developing psychiatric comorbidities. Alcohol use disorder (AUD) is the most prevalent psychiatric diagnosis preceding injury and TBI may increase subsequent alcohol use. The basolateral amygdala (BLA) is a limbic structure commonly affected by TBI that is implicated in anxiety and AUD. Endocannabinoids (eCBs) regulate synaptic activity in the BLA, and BLA eCB modulation alters anxiety-like behavior and stress reactivity. Previous work from our laboratories showed that systemic eCB degradation inhibition ameliorates TBI-induced increases in anxiety-like behavior and motivation to respond for alcohol in male rats. Here, we used a lateral fluid percussion model to test moderate TBI effects on anxiety-like behavior, alcohol drinking, and eCB levels and cell signaling in BLA, as well as the effect of alcohol drinking on anxiety-like behavior and the BLA eCB system, in female rats. Our results show that TBI does not promote escalation of operant alcohol self-administration or increase anxiety-like behavior in female rats. In the BLA, TBI and alcohol drinking alter tissue amounts of 2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine (anandamide; AEA) 1 h post-injury, and 2-AG levels remain low 11 days post-injury. Eleven days after injury, BLA pyramidal neurons were hyperexcitable, but measures of synaptic transmission and eCB signaling were unchanged. These data show that TBI impacts BLA 2-AG tissue levels, that this effect is modified by alcohol drinking, and also that TBI increases BLA cell excitability.

Cannabinoids as therapeutics for PTSD

Post-traumatic stress disorder (PTSD) is a complex disorder that involves dysregulation of multiple neurobiological systems. The traumatic stressor plays a causal role in producing psychological dysfunction and the pattern of findings suggests that the hypothalamic-pituitary-adrenal (HPA) axis, which is instrumental for stress adaptation, is critically dysfunctional in PTSD. Given the lack of understanding of the basic mechanisms and underlying pathways that cause the disorder and its heterogeneity, PTSD poses challenges for treatment. Targeting the endocannabinoid (ECB) system to treat mental disorders, and PTSD in particular, has been the focus of research and interest in recent years. The ECB system modulates multiple functions, and drugs enhancing ECB signaling have shown promise as potential therapeutic agents in stress effects and other psychiatric and medical conditions. In this review, we focus on the interaction between the ECB-HPA systems in animal models for PTSD and in patients with PTSD. We summarize evidence supporting the use of cannabinoids in preventing and treating PTSD in preclinical and clinical studies. As the HPA system plays a key role in the mediation of the stress response and the pathophysiology of PTSD, we describe preclinical studies suggesting that enhancing ECB signaling is consistent with decreasing PTSD symptoms and dysfunction of the HPA axis. Overall, we suggest that a pharmacological treatment targeted at one system (e.g., HPA) may not be very effective because of the heterogeneity of the disorder. There are abnormalities across different neurotransmitter systems in the pathophysiology of PTSD and none of these systems function uniformly among all patients with PTSD. Hence, conceptually, enhancing ECB signaling may be a more effective avenue for pharmacological treatment.

Sex differences in Alzheimer's disease: Understanding the molecular impact

Alzheimer's disease (AD) is a common neurodegenerative disorder that presents with cognitive impairment and behavioral disturbance. Approximately 5.5 million people in the United States live with AD, most of whom are over the age of 65 with two-thirds being woman. There have been major advancements over the last decade or so in the understanding of AD neuropathological changes and genetic involvement. However, studies of sex impact in AD have not been adequately integrated into the investigation of disease development and progression. It becomes indispensable to acknowledge in both basic science and clinical research studies the importance of understanding sex-specific differences in AD pathophysiology and pathogenesis, which could guide future effort in the discovery of novel targets for AD. Here, we review the latest and most relevant literature on this topic, highlighting the importance of understanding sex dimorphism from a molecular perspective and its association to clinical trial design and development in AD research field.