Psychiatric sequelae of traumatic brain injury - future directions in research

Poor long-term outcomes and abnormal neurodegeneration biomarkers after military traumatic brain injury: the ADVANCE study

BACKGROUND

Traumatic brain injury (TBI) is common in military campaigns and is a risk factor for dementia. ArmeD SerVices TrAuma and RehabilitatioN OutComE-TBI (ADVANCE-TBI) aims to ascertain neurological outcomes in UK military personnel with major battlefield trauma, leveraging advances in quantification of axonal breakdown markers like neurofilament light (NfL), and astroglial marker glial fibrillar acidic protein (GFAP) in blood. We aimed to describe the causes, prevalence and consequences of TBI, and its fluid biomarker associations.

METHODS

TBI history was ascertained in 1145 servicemen and veterans, of whom 579 had been exposed to major trauma. Functional and mental health assessments were administered, and blood samples were collected approximately 8 years postinjury, with plasma biomarkers quantified (n=1125) for NfL, GFAP, total tau, phospho-tau181, amyloid-β 42 and 40. Outcomes were related to neurotrauma exposure.

RESULTS

TBI was present in 16.9% (n=98) of exposed participants, with 46.9% classified as mild-probable and 53.1% classified as moderate to severe. Depression (β=1.65, 95% CI (1.33 to 2.03)), anxiety (β=1.65 (1.34 to 2.03)) and post-traumatic stress disorder (β=1.30 (1.19 to 1.41)) symptoms were more common after TBI, alongside poorer 6 minute walk distance (β=0.79 (0.74 to 0.84)) and quality of life (β=1.27 (1.19 to 1.36), all p<0.001). Plasma GFAP was 11% (95% CI 2 to 21) higher post-TBI (p=0.013), with greater concentrations in moderate-to-severe injuries (47% higher than mild-probable (95% CI 20% to 82%, p<0.001). Unemployment was more common among those with elevated GFAP levels post-TBI, showing a 1.14-fold increase (95% CI 1.03 to 1.27, p<0.001) for every doubling in GFAP concentration.

CONCLUSIONS

TBI affected nearly a fifth of trauma-exposed personnel, related to worse mental health, motor and functional outcomes, as well as elevated plasma GFAP levels 8 years post-injury. This was absent after extracranial trauma, and showed a dose-response relationship with the severity of the injury.

Impact of mild traumatic brain injury on health behaviors

Health-related behavioral changes may occur following traumatic brain injury. We focused on understanding the impact of mild traumatic brain injury (TBI) on health-related behaviors and identifying factors associated with such changes. We utilized health check-up records from the Korean National Health Insurance Service database spanning January 1, 2009, to December 31, 2017. The sample included 49,212 patients diagnosed with mild TBI and 1:1 matched controls who participated in national health check-ups in 2009-2010, 2011-2012, and 2016-2017. Multivariable logistic regression analysis was utilized to examine the association between mild TBI and short- and long-term health-related behavioral changes. Mild TBI was significantly associated with an increased risk of insufficient physical activity at the short- [odds ratio (OR), 1.04; 95% confidence interval (CI), 1.01 - 1.07] and long-term (OR, 1.06; 95% CI, 1.03 - 1.09) follow-ups. Age ≥ 65 years and female sex were significant effect modifiers for insufficient physical activity (OR, 1.11; 95% CI, 1.02 - 1.21) and smoking (OR, 1.31; 95% CI, 1.14 - 1.51), respectively. Mild TBI may lead to detrimental health-related behavioral changes, varying by age and sex. Thus, age- and sex-specific interventions may be needed to address these changes.

Traumatic Brain Injury and Risk of Incident Comorbidities

Importance

Traumatic brain injury (TBI) is associated with chronic medical conditions. Evidence from diverse clinical administrative datasets may improve care delivery.

Objective

To characterize post-TBI risk of incident neuropsychiatric and medical conditions in a California health care system administrative database and validate findings from a Massachusetts dataset.

Design, Setting, and Participants

In this cohort study, prospective longitudinal cohorts using data from 5 University of California health care settings between 2013 and 2022 were studied. Patients aged 18 years and older with mild (mTBI) or moderate to severe TBI (msTBI) were included. Unexposed individuals were propensity matched by age, race and ethnicity, sex, University of California site, insurance coverage, area deprivation index (ADI) score, and duration from index date to most recent clinical encounter. Patients with study comorbidities of interest before the index date were excluded. Data were analyzed August to October 2024.

Exposure

TBI.

Main Outcomes and Measures

International Classification of Diseases, Ninth Revision (ICD-9) and International Statistical Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes were used to identify patients with TBI and patients with up to 22 comorbidities within neurological, psychiatric, cardiovascular, and endocrine umbrella groupings. Cox proportional hazard models were used to generate yearly hazard ratios (HRs) from 6 months up to 10 years after a TBI. Models were further stratified by age and ADI score.

Results

The study consisted of 20 400 patients (9264 female [45.4%]; 1576 Black [7.7%], 3944 Latinx [19.3%], and 10 480 White [51.4%]), including 5100 patients with mTBI (median [IQR] age, 36.0 [25.0-51.0] years), 5100 patients with msTBI (median [IQR age, 35.0 [25.0-52.0] years), and 10 200 matched patients in the control group (median [IQR] age, 36.0 [25.0-51.0] years). By ADI score quintile, there were 2757 unexposed patients (27.0%), 1561 patients with mTBI (30.6%), and 1550 patients with msTBI (30.4%) in the lowest (1-2) quintiles and 1523 unexposed patients (14.9%), 769 patients with mTBI (15.1%), and 804 patients with msTBI (15.8%) in the highest quintiles (9-10). TBI of any severity was associated with increased risk of nearly all conditions (mTBI HRs ranged from 1.30; 95% CI, 1.07-1.57 for hypothyroidism to 4.06; 95% CI, 3.06-5.39 for dementia, and msTBI HRs ranged from 1.35; 95% CI, 1.12-1.62 for hypothyroidism to 3.45; 95% CI, 2.73-4.35 for seizure disorder). Separate age and ADI stratifications revealed patient populations at increased risk, including middle-age adults (ages 41-60 years), with increased risk of suicidality (mTBI: HR, 4.84; 95% CI, 3.01-7.78; msTBI: HR, 4.08; 95% CI, 2.51-6.62). Suicidality risk persisted for patients with mTBI in the high ADI subgroup (HR, 2.23; 95% CI, 1.36-3.66).

Conclusions and Relevance

In this cohort study, TBI was a risk factor associated with treatable incident neuropsychiatric and other medical conditions, validating similar findings from a Massachusetts dataset. Additional exploratory findings suggested varying demographic and regional risk patterns, which may generate causal hypotheses for further research and inform clinical surveillance strategies.

Risk factors for psychiatric disorders following traumatic brain injury: a multivariate logistic regression analysis

Objective

This study aimed to investigate the incidence and risk factors of psychiatric disorders following traumatic brain injury (TBI).

Methods

A total of 232 patients with closed TBI admitted to our hospital from January 2021 to January 2023 were included. Basic demographic data, injury circumstances, and psychiatric conditions during hospitalization were collected. Patients were followed up at 9 months post-injury, and based on clinical interviews, symptoms, and questionnaires, they were categorized into those with post-TBI psychiatric disorders and those without. The study aimed to explore the predictive factors for psychiatric disorders after TBI.

Results

Among the 232 patients, 104 developed psychiatric disorders by the end of the 9-month follow-up, resulting in an incidence rate of 44.83%. The employment rate was significantly lower in the psychiatric disorder group compared to the non-psychiatric disorder group. Additionally, the GCS scores upon admission were significantly higher in the psychiatric disorder group, along with a greater proportion of limb injuries, post-traumatic coma, intracranial hematomas, and frontal lobe injuries. The results of the multivariate logistic regression analysis indicated that unemployment (caused by poor recovery from TBI), lower GCS scores at admission, limb injuries, post-traumatic coma, frontal lobe injuries, and the presence of psychiatric symptoms during hospitalization were independent predictors of psychiatric disorders following TBI.

Conclusion

Unemployment, lower GCS score on admission, limb injury, post-traumatic coma, frontal lobe injury, onset of psychiatric symptoms during hospitalization was identified as independent predictors of post-traumatic psychiatric disorders. Routine mental health screenings for conditions such as depression and anxiety should be integrated into the care of TBI patients.

Small Molecule Hydrogels Loading Small Molecule Drugs from Chinese Medicine for the Enhanced Treatment of Traumatic Brain Injury

Self-assembly of hydrogels for mechanical support and drug delivery has been extensively researched in traumatic brain injury (TBI), where treatment options are limited. The chief challenge is that most self-assembled hydrogels rely on high molecular carriers or the incorporation of exogenous inactive substances as mediators. It is difficult for these drug delivery systems to achieve clinical translation due to concerns regarding biological safety. Here we report a small molecule hydrogel (GBR-gel) loading small molecule drugs (glycyrrhizic acid, berberine, and rhein) that originated from popular Chinese medicines without additional drug loading or inactive components under physiological conditions. In the long run, GBR-gel possesses several advantages, including ease of preparation, cost-effectiveness, and high biocompatibility. As a proof-of-concept, GBR-gel allows for prompt administration at the site of brain injury to exert potent pharmacodynamic effects. Further single-cell RNA sequencing and experimental validation indicated that GBR-gel can effectively rescue the suppressed glutamatergic synapse pathway after TBI, thereby attenuating inflammatory responses and neural impairments. Our work provides an alternative strategy for timely intervention of TBI.

Loss of microglial Arid1a exacerbates microglial scar formation via elevated CCL5 after traumatic brain injury

Traumatic brain injury (TBI) is an acquired insult to the brain caused by an external mechanical force, potentially resulting in temporary or permanent impairment. Microglia, the resident immune cells of the central nervous system, are activated in response to TBI, participating in tissue repair process. However, the underlying epigenetic mechanisms in microglia during TBI remain poorly understood. ARID1A (AT-Rich Interaction Domain 1 A), a pivotal subunit of the multi-protein SWI/SNF chromatin remodeling complex, has received little attention in microglia, especially in the context of brain injury. In this study, we generated a Arid1a cKO mouse line to investigate the potential roles of ARID1A in microglia in response to TBI. We found that glial scar formation was exacerbated due to increased microglial migration and a heightened inflammatory response in Arid1a cKO mice following TBI. Mechanistically, loss of ARID1A led to an up-regulation of the chemokine CCL5 in microglia upon the injury, while the CCL5-neutralizing antibody reduced migration and inflammatory response of LPS-stimulated Arid1a cKO microglia. Importantly, administration of auraptene (AUR), an inhibitor of CCL5, repressed the microglial migration and inflammatory response, as well as the glial scar formation after TBI. These findings suggest that ARID1A is critical for microglial response to injury and that AUR has a therapeutic potential for the treatment of TBI.

Cognitive and Salience Network Connectivity Changes following a Single Season of Repetitive Head Impact Exposure in High School Football

BACKGROUND AND PURPOSE

During a season of high school football, adolescents with actively developing brains experience a considerable number of head impacts. Our aim was to determine whether repetitive head impacts in the absence of a clinically diagnosed concussion during a season of high school football produce changes in cognitive performance or functional connectivity of the salience network and its central hub, the dorsal anterior cingulate cortex.

MATERIALS AND METHODS

Football players were instrumented with the Head Impact Telemetry System during all practices and games, and the helmet sensor data were used to compute a risk-weighted exposure metric (RWEcp), accounting for the cumulative risk during the season. Participants underwent MRI and a cognitive battery (ImPACT) before and shortly after the football season. A control group of noncontact/limited-contact-sport athletes was formed from 2 cohorts: one from the same school and protocol and another from a separate, nearly identical study.

RESULTS

Sixty-three football players and 34 control athletes were included in the cognitive performance analysis. Preseason, the control group scored significantly higher on the ImPACT Visual Motor (P = .04) and Reaction Time composites (P = .006). These differences increased postseason (P = .003, P < .001, respectively). Additionally, the control group had significantly higher postseason scores on the Visual Memory composite (P = .001). Compared with controls, football players showed significantly less improvement in the Verbal (P = .04) and Visual Memory composites (P = .01). A significantly greater percentage of contact athletes had lower-than-expected scores on the Verbal Memory (27% versus 6%), Visual Motor (21% versus 3%), and Reaction Time composites (24% versus 6%). Among football players, a higher RWEcp was significantly associated with greater increments in ImPACT Reaction Time (P = .03) and Total Symptom Scores postseason (P = .006). Fifty-seven football players and 13 control athletes were included in the imaging analyses. Postseason, football players showed significant decreases in interhemispheric connectivity of the dorsal anterior cingulate cortex (P = .026) and within-network connectivity of the salience network (P = .018). These decreases in dorsal anterior cingulate cortex interhemispheric connectivity and within-network connectivity of the salience network were significantly correlated with deteriorating ImPACT Total Symptom (P = .03) and Verbal Memory scores (P = .04).

CONCLUSIONS

Head impact exposure during a single season of high school football is negatively associated with cognitive performance and brain network connectivity. Future studies should further characterize these short-term effects and examine their relationship with long-term sequelae.

Social deficits mirror delayed cerebrovascular dysfunction after traumatic brain injury

Traumatic brain injury (TBI) survivors face debilitating long-term psychosocial consequences, including social isolation and depression. TBI modifies neurovascular physiology and behavior but the chronic physiological implications of altered brain perfusion on social interactions are unknown. Adult C57/BL6 male mice received a moderate cortical TBI, and social behaviors were assessed at baseline, 3-, 7-, 14-, 30-, and 60-days post injury (dpi). Magnetic resonance imaging (MRI, 9.4T) using dynamic susceptibility contrast perfusion weighted MRI were acquired. At 60dpi mice underwent histological angioarchitectural mapping. Analysis utilized standardized protocols followed by cross-correlation metrics. Social behavior deficits at 60dpi emerged as reduced interactions with a familiar cage-mate (partner) that mirrored significant reductions in cerebral blood flow (CBF) at 60dpi. CBF perturbations were dynamic temporally and across brain regions including regions known to regulate social behavior such as hippocampus, hypothalamus, and rhinal cortex. Social isolation in TBI-mice emerged with a significant decline in preference to spend time with a cage mate. Cortical vascular density was also reduced corroborating the decline in brain perfusion and social interactions. Thus, the late emergence of social interaction deficits mirrored the reduced vascular density and CBF in regions known to be involved in social behaviors. Vascular morphology and function improved prior to the late decrements in social function and our correlations strongly implicate a linkage between vascular density, cerebral perfusion, and social interactions. Our study provides a clinically relevant timeline of alterations in social deficits alongside functional vascular recovery that can guide future therapeutics.

Risk stratification of new-onset psychiatric disorders using clinically distinct traumatic brain injury phenotypes

BACKGROUND

Patients with traumatic brain injury (TBI) constitute a highly heterogeneous population, with varying risks for New-onset Psychiatric Disorders (NPDs). The objectives of this study were to identify TBI phenotypes and determine how NPDs differ among these phenotypes.

METHODS

Hospitalized TBI patients from 2003 to 2019 were obtained from the provincial trauma registry. Propensity score matching was conducted to balance covariates among patients with TBI and controls. To uncover heterogeneity in TBI, latent class analysis (LCA)-based clustering was applied. LCA was conducted separately for two TBI cohorts: those with and without pre-injury psychiatric conditions The effect of classes on NPDs was assessed using log binomial regression models.

RESULTS

A total of 3,453 patients with TBI and 13,112 controls were included in the analysis. In a conditional regression involving propensity matched patients with TBI and controls, TBI was significantly associated with the development of NPD-A (OR: 2.78; 95% CI: 2.49-3.09), as well as NPD-P (OR: 2.36; 95% CI: 2.07-2.70). Eight distinct latent classes were identified which differed in the incidence of NPDs. Four classes displayed a 53% (RR:1.53; 95% CI: 1.31-1.78), 48% (RR:1.48; 95% CI: 1.26-1.74), 28% (RR:1.28; 95% CI: 1.08-1.54), and 20% (RR: 1.20, 95%CI: 1.03-1.39), increased NPD risk.

CONCLUSION

TBI is a significant predictor of NPDs. There are clinically distinguishable phenotypes with different patterns of NPD risk among patients with TBI. Identifying individuals with respect to their phenotype may improve risk stratification of patients with TBI and promote early intervention for psychiatric care in this vulnerable population.

A Transdiagnostic, Hierarchical Taxonomy of Psychopathology Following Traumatic Brain Injury (HiTOP-TBI)

Psychopathology, including depression, anxiety, and post-traumatic stress, is a significant yet inadequately addressed feature of moderate-severe traumatic brain injury (TBI). Progress in understanding and treating post-TBI psychopathology may be hindered by limitations associated with conventional diagnostic approaches, specifically the Diagnostic and Statistical Manual of Mental Disorders (DSM) and International Classification of Diseases (ICD). The Hierarchical Taxonomy of Psychopathology (HiTOP) offers a promising, transdiagnostic alternative to psychiatric classification that may more effectively capture the experiences of individuals with TBI. However, HiTOP lacks validation in the TBI population. To address this gap, we administered a comprehensive questionnaire battery, including 56 scales assessing homogeneous symptom components and maladaptive traits within HiTOP, to 410 individuals with moderate-severe TBI. We evaluated the reliability and unidimensionality of each scale and revised those with psychometric problems. Using a top-down, exploratory latent variable approach (bass-ackwards modeling), we subsequently constructed a hierarchical model of psychopathological dimensions tailored to TBI. The results showed that, relative to norms, participants with moderate-severe TBI experienced greater problems in the established HiTOP internalizing and detachment spectra, but fewer problems with thought disorder and antagonism. Fourteen of the 56 scales demonstrated psychometric problems, which often appeared reflective of the TBI experience and associated disability. The Hierarchical Taxonomy of Psychopathology Following Traumatic Brain Injury (HiTOP-TBI) model encompassed broad internalizing and externalizing spectra, splitting into seven narrower dimensions: Detachment, Dysregulated Negative Emotionality, Somatic Symptoms, Compensatory and Phobic Reactions, Self-Harm and Psychoticism, Rigid Constraint, and Harmful Substance Use. This study presents the most comprehensive empirical classification of psychopathology after TBI to date. It introduces a novel, TBI-specific transdiagnostic questionnaire battery and model, which addresses the limitations of conventional DSM and ICD diagnoses. The empirical structure of psychopathology after TBI largely aligned with the established HiTOP model (e.g., a detachment spectrum). However, these constructs need to be interpreted in relation to the unique experiences associated with TBI (e.g., considering the injury's impact on the person's social functioning). By overcoming the limitations of conventional diagnostic approaches, the HiTOP-TBI model has the potential to accelerate our understanding of the causes, correlates, consequences, and treatment of psychopathology after TBI.

Aqueous Grown Quantum Dots with Robust Near-Infrared Fluorescence for Integrated Traumatic Brain Injury Diagnosis and Surgical Monitoring

Surgical intervention is the most common first-line treatment for severe traumatic brain injuries (TBIs) associated with high intracranial pressure, while the complexity of these surgical procedures often results in complications. Surgeons often struggle to comprehensively evaluate the TBI status, making it difficult to select the optimal intervention strategy. Here, we introduce a fluorescence imaging-based technology that uses high-quality silver indium selenide-based quantum dots (QDs) for integrated TBI diagnosis and surgical guidance. These engineered, poly(ethylene glycol)-capped QDs emit in the near-infrared region, are resistant to phagocytosis, and importantly, are ultrastable after the epitaxial growth of an aluminum-doped zinc sulfide shell in the aqueous phase that renders the QDs resistant to long-term light irradiation and complex physiological environments. We found that intravenous injection of QDs enabled both the precise diagnosis of TBI in a mouse model and, more importantly, the comprehensive evaluation of the TBI status before, during, and after an operation to distinguish intracranial from superficial hemorrhages, provide real-time monitoring of the secondary hemorrhage, and guide the decision making on the evacuation of intracranial hematomas. This QD-based diagnostic and monitoring system could ultimately complement existing clinical tools for treating TBI, which may help surgeons improve patient outcomes and avoid unnecessary procedures.

The Effects of Early Life History of TBI on the Progression of Normal Brain Aging with Implications for Increased Dementia Risk

There is increasing interest in the risk conferred on neurological health by a traumatic brain injury (TBI) and how that influences the lifespan trajectory of brain aging. This chapter explores the importance of this issue, population, and methodological considerations, including injury documentation and outcome assessment. We then explore some of the findings in the neuroimaging and neuropsychological research literature examining the interaction between an earlier life history of TBI and the normal aging process. Finally, we consider the limitations of our current knowledge and where the field needs to go in the future.

Clinical and Neuropathological Correlates of Substance Use in American Football Players

Background

Chronic traumatic encephalopathy (CTE) is a neurodegenerative tauopathy more frequently found in deceased former football players. CTE has heterogeneous clinical presentations with multifactorial causes. Previous literature has shown substance use (alcohol/drug) can contribute to Alzheimer's disease and related tauopathies pathologically and clinically.

Objective

To examine the association between substance use and clinical and neuropathological endpoints of CTE.

Methods

Our sample included 429 deceased male football players. CTE was neuropathologically diagnosed. Informant interviews assessed features of substance use and history of treatment for substance use to define indicators: history of substance use treatment (yes vs no, primary variable), alcohol severity, and drug severity. Outcomes included scales that were completed by informants to assess cognition (Cognitive Difficulties Scale, BRIEF-A Metacognition Index), mood (Geriatric Depression Scale-15), behavioral regulation (BRIEF-A Behavioral Regulation Index, Barratt Impulsiveness Scale-11), functional ability (Functional Activities Questionnaire), as well as CTE status and cumulative p-tau burden. Regression models tested associations between substance use indicators and outcomes.

Results

Of the 429 football players (mean age = 62.07), 313 (73%) had autopsy confirmed CTE and 100 (23%) had substance use treatment history. Substance use treatment and alcohol/drug severity were associated with measures of behavioral regulation (FDR-p-values<0.05, ΔR2 = 0.04-0.18) and depression (FDR-p-values<0.05, ΔR2 = 0.02-0.05). Substance use indicators had minimal associations with cognitive scales, whereas p-tau burden was associated with all cognitive scales (p-values <0.05). Substance use treatment had no associations with neuropathological endpoints (FDR-p-values>0.05).

Conclusions

Among deceased football players, substance use was common and associated with clinical symptoms.

Bipolar Disorder Due to Traumatic Brain Injury: A Case Report

I report an unusual case in Saudi Arabia of a 28-year-old man who had bipolar disorder due to a traumatic brain injury suffered 10 years previously. He had been evaluated and diagnosed with schizoaffective disorder as well as amphetamine and hash use disorder until recently, when the team noticed a poor response to treatment and the continuation of his cognitive features. After a reevaluation of the history and evidence of the brain lesions on the MRI, the diagnosis was changed to bipolar disorder due to a traumatic brain injury. The patient had shown a fair response to valproate and risperidone. This report emphasizes the significance of ruling out the medical factors contributing to the manifestation of any novel psychiatric symptom, necessitating greater attention to the account of cranial trauma and periods of unconsciousness. Psychiatrists should be aware of these overlooked cases and encourage colleagues in the field to maintain a high index of suspicion and to take a good relevant history of brain injury insults, especially when there are cognitive features and a poor response to medications. The patient exhibited symptoms of inattention, memory difficulties, reasoning deficits, and poor judgment, but he did not meet the criteria for a minor or major cognitive disorder.