The Association between Psychiatric Comorbidities and Outcomes for Inpatients with Traumatic Brain Injury

Traumatic Brain Injury, Psychological Trauma Exposure, and Anxious and Depressive Symptoms in a Clinical Population

BACKGROUND

Approximately 90% of adults endorse psychological trauma exposure. However, barriers to assessment of psychological trauma and sequelae include limited access to care, lack of standardized assessments in nonpsychiatric settings, and comorbid diagnoses, such as traumatic brain injury (TBI), that may mimic psychiatric syndromes.

OBJECTIVES

This study aims to assess the prevalence rates of psychological trauma exposure and TBI to understand the relationship of these experiences with current psychiatric symptoms.

METHODS

This is a cross-sectional study of a convenience sample of adult patients (age 18 years and older) referred for outpatient evaluation at a neuropsychology clinic in the Western United States between September 2021 and October 2022. Patients completed a clinical interview to assess their history of psychological trauma, TBI, and current psychiatric symptoms.

RESULTS

A total of 118 patients met inclusion criteria. Patients in the TBI group (n = 83) endorsed significantly higher rates of childhood trauma and prior physical, emotional, and sexual abuse compared with the No TBI group (n = 35). Psychological trauma exposure and TBI significantly predicted current anxiety and depressive symptoms, but there was no interaction between these experiences in predicting current psychiatric symptoms.

CONCLUSIONS

Individuals with prior TBI experienced psychological trauma, particularly childhood trauma, at a significantly higher rate than those without TBI. Psychological trauma exposure and TBI independently predicted anxious and depressive symptoms, suggesting both may be viable treatment targets. Evaluation of prior psychological trauma exposure during evaluation of TBI may provide opportunities for trauma-informed care and may allow for improved outpatient treatment planning.

Psychosocial functioning mediates change in motor and cognitive function throughout neurorehabilitation for adults with acquired brain injury (ABI-RESTaRT)

OBJECTIVES

This study aimed to evaluate the mediational role of change in psychosocial abilities, adjustment and participation on change in motor and cognitive function from admission to discharge from a staged community-based brain injury rehabilitation (SCBIR) service in Western Australia, 2011-2020.

METHODS

A retrospective cohort study of n = 324 adults with ABI enrolled in SCBIR using routinely collected rehabilitation outcome measures data. Motor and cognitive function were assessed with the UK Functional Independence and Assessment Measure and psychosocial function with the Mayo-Portland Adaptability Inventory-4. Six multilevel mediation regression analyses were conducted to determine whether change in psychosocial function (abilities, adjustment and participation) mediated change in motor and cognitive function from admission to discharge.

RESULTS

Participants demonstrated clinically significant improvements in both motor (+ 11.8, p < 0.001) and cognitive (+ 9.5, p < 0.001) functioning from admission to discharge. Statistically significant improvements in psychosocial abilities (- 4.8, p < 0.001), adjustment (- 2.9, p = 0.001) and participation (- 2.5, p < 0.001) were also seen but were not clinically significant. Mediation analyses showed that participation accounted for 81% of improvements in motor function at discharge and 71% of cognitive function improvements. Adjustment accounted for 26% and 32% of change in motor and cognitive function, respectively. Abilities accounted for 60% of change in cognitive function but did not significantly influence change in motor function. Changes in psychosocial participation fully mediated change in motor function during neurorehabilitation.

CONCLUSIONS

Psychosocial function, particularly participation, is an important driver of motor and cognitive recovery throughout neurorehabilitation. Functional rehabilitation programs should target psychosocial improvement as an important mechanism of change.

Effects of comorbidity on post-acute outcomes in acquired brain injury: ABI-RESTaRT 1991-2020

BACKGROUND

Current understanding of comorbidities associated with acquired brain injury (ABI) and the effects on post-acute ABI outcomes is poor.

OBJECTIVE

To describe the prevalence, severity and patterns of comorbidity for the pre-injury, acute and post-acute phases, and to examine the effects of post-acute comorbidities on functional independence and length of stay (LOS) at discharge from post-acute care.

METHODS

Retrospective whole-population cohort study of n = 1,011 individuals with traumatic (TBI) or non-traumatic brain injury (NTBI), or eligible neurologic conditions admitted to a post-acute neurorehabilitation and disability support service in Western Australia (WA) between 1991 and 2020. Comorbidities were ascertained from internal electronic medical records and linked hospital and emergency department data from the WA Data Linkage System. We measured comorbidities across 14 body systems using the Cumulative Illness Rating Scale (CIRS) and Elixhauser Comorbidity Index (ECI), and functional independence with the UK Functional Independence Measure and Functional Assessment Measure (UK FIM+FAM). We used multilevel mixed-effect regression models to determine the effects of comorbidity on post-acute outcomes.

RESULTS

NTBI was the most common diagnosis (54%), followed by TBI (34%) and neurologic conditions (10%). Pre-injury comorbidities were present in over half the cohort. Comorbidity prevalence increased significantly from 57% to 84% (∆+27%) and severity (mean ECI score) increased significantly from 2.1 to 13.8 (∆+11.7) between pre-injury and the acute phase and remained elevated at admission to post-acute services (82%, mean ECI score 7.3). Psychiatric comorbidity was the most prevalent (56%) and was associated with significantly poorer functional outcomes at discharge and an increase in LOS of 6.5 months. Genitourinary, musculoskeletal, eye, ear nose and throat, and renal comorbidities also had significant effects on post-acute outcomes.

CONCLUSIONS

ABI has a long-term impact on multiple body systems. Identification and management of comorbidities is critical to maximize functional outcomes and reduce the cost of post-acute care.

Preinjury Functional Independence is not Associated with Discharge Location in Older Trauma Patients

BACKGROUND

The purpose of this study was to evaluate the association between pre-injury Katz Index of Independence in Activities of Daily Living (Katz ADL) functional status and discharge to a facility in non-neurologically injured older trauma patients.

METHODS

Data were obtained from 207 patients in the Trauma Medical Home study cohort. Multivariable logistic regression was performed to identify factors associated with non-home discharge.

RESULTS

Average patient age was 67.9 (SD 11.1). Patients were predominantly white (89.4%) and female (52.2%) with a median ISS of 11 (IQR 9-14). The most common mechanism of injury was fall (48.3%), followed by motor vehicle crash (41.1%). Nearly all patients (94.7%) reported independence in activities of daily living prior to hospitalization for injury. Discharge disposition varied, 51.7% of patients were discharged home, 37.7% to subacute rehabilitation, 10.1% to acute rehabilitation and 0.5% to long-term acute care. There was no relationship between pre-injury independence and likelihood of discharge home (P = 0.1331). Age (P < 0.0001), BMI (P = 0.0002), Charlson comorbidity score of 3 or greater (P = 0.0187), being single (P = 0.0077), ISS ≥ 16 (P = 0.0075) and being female with self-reported symptoms of anxiety and/or depression over the past two weeks (P = 0.0092) were associated with significantly greater odds of non-home discharge.

CONCLUSIONS

Pre-injury Katz ADL is not associated with discharge disposition, though other significantly associated factors were identified. It is imperative that discussions regarding discharge disposition are initiated early during acute hospitalization. Trauma programs could potentially benefit from implementing an inpatient intervention focused on building coping skills for older patients exhibiting symptoms of anxiety or depression.

Impact of Curcumin on Traumatic Brain Injury and Involved Molecular Signaling Pathways

Traumatic Brain Injury (TBI) is one of the main causes of mortality and morbidity worldwide with no suitable treatment. The present study was designed to review the present literature about the protective effects of curcumin and the underlying mechanism against TBI. All published English language papers from beginning to 2019 were selected in this study. The findings indicate that curcumin may be effective against TBI outcomes by modulating the molecular signaling pathways involved in oxidative stress, inflammation, apoptosis, and autophagy. However, more experimental studies should be done to identify all mechanisms involved in the pathogenesis of TBI. Patents for Curcumin and chronic inflammation and traumatic brain injury management (WO2017097805A1 and US9101580B2) were published. In conclusion, the present study confirmed the potential therapeutic impact of curcumin for treating TBI.

Pre-existing psychiatric disorder is related to lower mortality from road traffic accident: A Japanese nationwide retrospective cohort study

BACKGROUND

Previous studies have reported inconsistent results on the mortality from trauma among psychiatric patients comparing to non-psychiatric population, which may be partly explained by the inclusion of both suicidal and accidental trauma. This study aimed to investigate the association of psychiatric diagnoses on admission with the outcomes of hospitalized patients for accidental trauma, namely road traffic injury.

METHODS

Detailed information of patients aged 15 years or older who were hospitalized for road traffic injury between 2004 and 2017 was extracted from the Japan Trauma Data Bank. The primary outcome was to compare in-hospital mortality between patients with and without a psychiatric disorder. We also conducted a subgroup analysis among patients with and without a serious head injury.

RESULTS

Altogether, 85,069 patients were included. Of these, 3,895 patients (4.6%) had a psychiatric diagnosis. The in-hospital mortality rate was significantly lower among patients with a psychiatric diagnosis than those without (5.4% vs. 8.3%; adjusted odds ratio [OR] 0.57, 95% confidence interval [CI] 0.47-0.70, p<0.001). In a subgroup analysis of patients with a serious head injury, in-hospital mortality was significantly lower in patients with a psychiatric diagnosis than in those without (10.5% vs. 17.3%; adjusted OR 0.48, 95% CI 0.37-0.62, p<0.001); in-hospital mortality of patients without a serious head injury showed no differences between patients with or without a psychiatric diagnosis (2.8% vs. 3.5%; adjusted OR 0.84, 95% CI 0.61-1.16, p=0.295).

CONCLUSIONS

In-hospital mortality from road traffic injury was significantly lower among patients with a psychiatric diagnosis than those without, which was primarily evident in a subgroup of patients with a serious head injury. While further replication is necessary, results might be indicative of the neuroprotective effect of psychotropic medications.

Cross-sectional study of major procedure codes among hospitalized patients with traumatic brain injury by level of injury severity in the 2004 to 2014 Nationwide Inpatient Sample

Despite its public health significance, TBI management across US healthcare institutions and patient characteristics with an emphasis on utilization and outcomes of TBI-specific procedures have not been evaluated at the national level.We aimed to characterize top 10 procedure codes among hospitalized adults with TBI as primary diagnosis by injury severity.A Cross-sectional study was conducted using 546, 548 hospitalization records from the 2004 to 2014 Nationwide Inpatient Sample were analyzed.Data elements of interest included injury, patient, hospital characteristics, procedures, in-hospital death and length of stay.Ten top procedure codes were "Closure of skin and subcutaneous tissue of other sites", "Insertion of endotracheal tube", "Continuous invasive mechanical ventilation for less than 96 consecutive hours", "Venous catheterization (not elsewhere classified)", "Continuous invasive mechanical ventilation for 96 consecutive hours or more", "Transfusion of packed cells", "Incision of cerebral meninges", "Serum transfusion (not elsewhere classified)", "Temporary tracheostomy", and "Arterial catherization". Prevalence rates ranged between 3.1% and 15.5%, with variations according to injury severity and over time. Whereas "Closure of skin and subcutaneous tissue of other sites" was associated with fewer in-hospital deaths and shorter hospitalizations, "Temporary tracheostomy" was associated with fewer in-hospital deaths among moderate-to-severe TBI patients, and "Continuous invasive mechanical ventilation for less than 96 consecutive hours" was associated with shorter hospitalizations among severe TBI patients. Other procedures were associated with worse outcomes.Nationwide, the most frequently reported hospitalization procedure codes among TBI patients aimed at homeostatic stabilization and differed in prevalence, trends, and outcomes according to injury severity.

Comorbidity in traumatic brain injury and functional outcomes: a systematic review

INTRODUCTION

Comorbidities in people with traumatic brain injury (TBI) may negatively impact injury recovery course and result in long-term disability. Despite the high prevalence of several categories of comorbidities in TBI, little is known about their association with patients' functional outcomes. We aimed to systematically review the current evidence to identify comorbidities that affect functional outcomes in adults with TBI.

EVIDENCE ACQUISITION

A systematic search of Medline, Cochrane Central Register of Controlled Trials, Embase and PsycINFO was conducted from 1997 to 2020 for prospective and retrospective longitudinal studies published in English. Three researchers independently screened and assessed articles for fulfillment of the inclusion criteria. Quality assessment followed the Quality in Prognosis Studies tool and the Scottish Intercollegiate Guidelines Network methodology recommendations.

EVIDENCE SYNTHESIS

Twenty-two studies of moderate quality discussed effects of comorbidities on functional outcomes of patients with TBI. Cognitive and physical functioning were negatively affected by comorbidities, although the strength of association, even within the same categories of comorbidity and functional outcome, differed from study to study. Severity of TBI, sex/gender, and age were important factors in the relationship. Due to methodological heterogeneity between studies, meta-analyses were not performed.

CONCLUSIONS

Emerging evidence highlights the adverse effect of comorbidities on functional outcome in patients with TBI, so clinical attention to this topic is timely. Future research on the topic should emphasize time of comorbidity onset in relation to the TBI event, to support prevention, treatment, and rehabilitation. PROSPERO registration (CRD 42017070033).

Developing an Index of Medical Conditions Associated with Outcomes after Moderate-to-Severe Traumatic Brain Injury

Medical conditions co-occurring with traumatic brain injury (TBI) are associated with outcomes, and comorbidity indices such as Charlson and Elixhauser are used in TBI research, but they are not TBI specific. The purpose of this research was to develop an index or indices of medical conditions, identified in acute care after moderate to severe TBI, that are associated with outcomes at rehabilitation discharge. Using the TBI Model Systems National Database, the International Classification of Diseases, Ninth Revision (ICD-9) and Tenth Revision (ICD-10) codes of 8988 participants were converted to Healthcare Cost and Utilization Project (HCUP) diagnostic categories. Poisson regression models were built predicting Disability Rating Scale and Functional Independence Measure Cognitive and Motor subscale scores from HCUP categories after controlling for demographic and injury characteristics. Unweighted, weighted, and anchored indices based on the outcome models predicted 7.5-14.3% of the variance in the observed outcomes. When the indices were applied to a new validation sample of 1613 cases, however, only 2.6-6.6% of the observed outcomes were predicted. Therefore, no models or indices were recommended for future use, but several study findings are highlighted suggesting the importance and the potential for future research in this area.

A Multi-Modal Assessment of Clinical Predictors for Traumatic Brain Injury End-Points

Traumatic brain injury (TBI) is a complex injury that has a multi-faceted recovery process. The current "gold standard" for classifying severity of TBI symptoms is the Glasgow Outcome Scale (GOSE), a crude measure of overall dysfunction after TBI. Exploratory factor analysis performed on TRACK-TBI Pilot (N = 297) identified candidate multi-variate outcome measures of neuropsychological impairment and cognitive speed and flexibility at 6 months post-TBI that were confirmed in data from the COBRIT study (N = 645) using confirmatory factor analysis. These new outcome measures were used as the dependent variables in an ordinal logistic regression model, using common data elements (CDE) collected in the emergency department as independent variables, including basic demographics, socioeconomic status, medical history, and measures of blood alcohol and blood pressure. We directly compared these prediction models with the GOSE as the 6-month outcome variable and found that in both the TRACK-TBI pilot and COBRIT studies, both neuropsychiatric complications (approx. 36.0% and 22.3% variance explained) and cognitive speed and flexibility (approx. 33.9% and 24.5% variance explained) were better explained by the prediction model, compared with GOSE (approx. 19.9% and 14.4% variance explained), respectively. While differences in overall distributions of impairment between TRACK-TBI pilot and COBRIT exist and should be explored further for applications of these prediction models, we think these multi-variate end-points more accurately characterize patients' functioning at six-months post-TBI. A multi-variate assessment of end-points seems especially important for characterizing TBI outcomes in cases where gross impairment, such as those measured by the GOSE, may be less evident.

Two latent classes of diagnostic and treatment procedures among traumatic brain injury inpatients

To characterize latent classes of diagnostic and/or treatment procedures among hospitalized U.S. adults, 18–64 years, with primary diagnosis of TBI from 2004–2014 Nationwide Inpatient Samples, latent class analysis (LCA) was applied to 10 procedure groups and differences between latent classes on injury, patient, hospital and healthcare utilization outcome characteristics were modeled using multivariable regression. Using 266,586 eligible records, LCA resulted in two classes of hospitalizations, namely, class I (n = 217,988) (mostly non-surgical) and class II (n = 48,598) (mostly surgical). Whereas orthopedic procedures were equally likely among latent classes, skin-related, physical medicine and rehabilitation procedures as well as behavioral health procedures were more likely among class I, and other types of procedures were more likely among class II. Class II patients were more likely to have moderate-to-severe TBI, to be admitted on weekends, to urban, medium-to-large hospitals in Midwestern, Southern or Western regions, and less likely to be > 30 years, female or non-White. Class II patients were also less likely to be discharged home and necessitated longer hospital stays and greater hospitalization charges. Surgery appears to distinguish two classes of hospitalized patients with TBI with divergent healthcare needs, informing the planning of healthcare services in this target population.

Comorbidity in adults with traumatic brain injury and all-cause mortality: a systematic review

OBJECTIVES

Comorbidity in traumatic brain injury (TBI) has been recognised to alter the clinical course of patients and influence short-term and long-term outcomes. We synthesised the evidence on the effects of different comorbid conditions on early and late mortality post-TBI in order to (1) examine the relationship between comorbid condition(s) and all-cause mortality in TBI and (2) determine the influence of sociodemographic and clinical characteristics of patients with a TBI at baseline on all-cause mortality.

DESIGN

Systematic review.

DATA SOURCES

Medline, Central, Embase, PsycINFO and bibliographies of identified articles were searched from May 1997 to January 2019.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Included studies met the following criteria: (1) focused on comorbidity as it related to our outcome of interest in adults (ie, ≥18 years of age) diagnosed with a TBI; (2) comorbidity was detected by any means excluding self-report; (3) reported the proportion of participants without comorbidity and (4) followed participants for any period of time.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers extracted the data and assessed risk of bias using the Quality in Prognosis Studies tool. Data were synthesised through tabulation and qualitative description.

RESULTS

A total of 27 cohort studies were included. Among the wide range of individual comorbid conditions studied, only low blood pressure was a consistent predictors of post-TBI mortality. Other consistent predictors were traditional sociodemographic risk factors. Higher comorbidity scale, scores and the number of comorbid conditions were not consistently associated with post-TBI mortality.

CONCLUSIONS

Given the high number of comorbid conditions that were examined by the single studies, research is required to further substantiate the evidence and address conflicting findings. Finally, an enhanced set of comorbidity measures that are suited for the TBI population will allow for better risk stratification to guide TBI management and treatment.

PROSPERO REGISTRATION NUMBER

CRD42017070033.

Patients with stroke and psychiatric comorbidities have lower carotid revascularization rates

OBJECTIVE

We investigated whether mental illness is associated with lower rates of carotid endarterectomy (CEA)/carotid artery stenting (CAS) after stroke due to carotid stenosis.

METHODS

In this retrospective cross-sectional study, ischemic stroke cases due to carotid stenosis were identified in the 2007-2014 Nationwide (National) Inpatient Sample. Psychiatric conditions were identified by secondary ICD-9-CM diagnosis codes for schizophrenia/psychoses, bipolar disorder, depression, anxiety, or substance use disorders. Using logistic regression, we tested the association between psychiatric conditions and CEA/CAS, controlling for demographic, clinical, and hospital factors.

RESULTS

Among 37,474 included stroke cases, 6,922 (18.5%) had a psychiatric comorbidity. The presence of any psychiatric condition was associated with lower odds of CEA/CAS (adjusted odds ratio [OR] 0.84, 95% confidence interval [CI] 0.78-0.90). Schizophrenia/psychoses (OR 0.72, 95% CI 0.55-0.93), depression (OR 0.83, 95% CI 0.75-0.91), and substance use disorders (OR 0.73, 95% CI 0.65-0.83) were each associated with lower odds of CEA/CAS. The association of mental illness and CEA/CAS was dose-dependent: compared to patients without mental illness, patients with multiple psychiatric comorbidities (OR 0.74, 95% CI 0.62-0.87) had lower odds of CEA/CAS than those with only one psychiatric comorbidity (OR 0.86, 95% CI 0.79-0.92; p value for trend <0.001).

CONCLUSION

The odds of carotid revascularization after stroke is lower in patients with mental illness, particularly those with schizophrenia/psychoses, depression, substance use disorders, and multiple psychiatric diagnoses.

Efficacy of sertraline in post-traumatic brain injury (post-TBI) depression and quality of life: A systematic review and meta-analysis of randomized controlled trials

The relative paucity of robust studies on pharmacological treatments for depression following traumatic brain injury precludes establishment of firm recommendations for its routine use in this population. The purpose of this study is to determine the efficacy and tolerability of sertraline in the treatment of post-TBI depression and improvement in quality of life. Randomized controlled trials (RCT) were identified by electronic search through PubMed, Scopus, CINAHL (Cumulative Index to Nursing and Allied Health Literature), LILACS (Literatura Latino-Americana e do Caribe em Ciencas da Saude), Cochrane Library, Clinicaltrials.gov, and HERDIN (Health Research and Development Information Network database). Random effects meta-analysis of data for depression scale scores, treatment response, and quality of life scale scores was conducted. Four RCTs were included with a total of 224 patients. There were no significant mean differences in the Hamilton Depression Rating Scale (HAM-D17) scores (MD = 2.63, 95% CI [-1.32,6.57], p = 0.19), Maier subscale scores (MD = 0.88, 95% CI [-2.26, 4.01], p = 0.58), odds ratio of treatment response (OR = 1.04, 95% CI [0.13, 8.43], p = 0.97) and quality of life scale scores (SMD = -1.52, 95% CI [-5.65, 2.61], p = 0.47) between sertraline and placebo. The pooled evidence from four RCTs shows that sertraline is not superior to placebo in terms of improving depression and quality of life of patients with post-TBI depression. There is also insufficient evidence regarding its safety in this subset of patients.

Neuroendocrine Abnormalities Following Traumatic Brain Injury: An Important Contributor to Neuropsychiatric Sequelae

Neuropsychiatric symptoms following traumatic brain injury (TBI) are common and contribute negatively to TBI outcomes by reducing overall quality of life. The development of neurobehavioral sequelae, such as concentration deficits, depression, anxiety, fatigue, and loss of emotional well-being has historically been attributed to an ambiguous "post-concussive syndrome," considered secondary to frank structural injury and axonal damage. However, recent research suggests that neuroendocrine dysfunction, specifically hypopituitarism, plays an important role in the etiology of these symptoms. This post-head trauma hypopituitarism (PHTH) has been shown in the past two decades to be a clinically prevalent phenomenon, and given the parallels between neuropsychiatric symptoms associated with non-TBI-induced hypopituitarism and those following TBI, it is now acknowledged that PHTH is likely a substantial contributor to these impairments. The current paper seeks to provide an overview of hypothesized pathophysiological mechanisms underlying neuroendocrine abnormalities after TBI, and to emphasize the significance of this phenomenon in the development of the neurobehavioral problems frequently seen after head trauma.

Depression in Men and Women One Year Following Traumatic Brain Injury (TBI): A TBI Model Systems Study

In the general population, females experience depression at significantly higher rates than males. Individuals with traumatic brain injury (TBI) are at substantially greater risk for depression compared to the overall population. Treatment of, and recovery from, TBI can be hindered by depression; comorbid TBI and depression can lead to adverse outcomes and negatively affect multiple aspects of individuals’ lives. Gender differences in depression following TBI are not well understood, and relevant empirical findings have been mixed. Utilizing the Patient Health Questionnaire-9 (PHQ-9) 1 year after TBI, we examined whether women would experience more severe depressive symptoms, and would endorse higher levels of depression within each category of depression severity, than would men. Interestingly, and contrary to our hypothesis, men and women reported mild depression at equal rates; PHQ-9 total scores were slightly lower in women than in men. Men and women did not differ significantly in any PHQ-9 depression severity category. Item analyses, yielded significant gender differences on the following items: greater concentration difficulties (cognitive problems) in men and more sleep disturbances (psychosomatic issues) in women per uncorrected two-sample Z-test for proportions analyses; however, these results were not significant after the family-wise Bonferroni correction. Our results indicate that, in contrast to the general population, mild depression in persons with moderate to severe TBI may not be gender-specific. These findings underscore the need for early identification, active screening, and depression treatment equally for men and women to improve emotional well-being, promote recovery, and enhance quality of life following TBI.

Therapeutic Potentials of Synapses after Traumatic Brain Injury: A Comprehensive Review

Massive studies have focused on the understanding of the pathobiology of cellular and molecular changes and injury mechanisms after traumatic brain injury (TBI), but very few studies have specially discussed the role of synapses in the context of TBI. This paper specifically highlights the role and therapeutic potentials of synapses after TBI. First, we review and conclude how synapses interact with constant structural, metabolic, neuroendocrine, and inflammatory mechanisms after TBI. Second, we briefly describe several key synaptic proteins involved in neuroplasticity, which may be novel neuronal targets for specific intervention. Third, we address therapeutic interventions in association with synapses after TBI. Finally, we concisely discuss the study gaps in the synapses after TBI, in hopes that this would provide more insights for future studies. Synapses play an important role in TBI; while the understandings on the synaptic participation in the treatments and prognosis of TBI are lacking, more studies in this area are warranted.