Traumatic Brain Injury History Among Individuals Using Mental Health and Addictions Services: A Scoping Review

Abstract

Objective: 

Traumatic brain injury (TBI) has been increasingly linked in population research to psychiatric problems as well as substance use and related harms, suggesting that individuals with TBI may also present more frequently to mental health and addictions (MHA) services. Little is known, however, about TBI history among MHA service users. The objectives of this review were to understand (i) the prevalence of TBI history among MHA service users; (ii) how TBI history is identified in MHA service settings; and (iii) predictors or outcomes of TBI that have been reported in MHA service users.

Methods: 

A scoping review was conducted in accordance with PRISMA Scoping Review Extension guidelines. A search for relevant literature was conducted in MEDLINE, PsycINFO, SPORTDiscus, CINAHL, and Embase as well as various gray literature sources.

Results: 

Twenty-eight relevant studies were identified. TBI was defined and operationalized heterogeneously between studies, and TBI history prevalence rates ranged considerably among the study samples. The included studies used varied methods to identify TBI history in MHA settings, such as clinical chart audits, single-item questions, or structured questionnaires (eg, Brain Injury Screening Questionnaire or Ohio State University TBI Identification Method). TBI history was most consistently associated with indicators of more severe substance use problems and mental health symptoms as well as increased aggression or risk to others. Studies reported less consistent findings regarding the relationship of TBI to physical health, cognitive impairment, functioning, risk to self, and type of psychiatric diagnosis.

Conclusion: 

Screening for TBI history in MHA settings may contribute important information for risk assessment and care planning. However, to be clinically useful, assessment of TBI history will require consistent operationalization of TBI as well as use of validated screening methods.

EVIDENCE IS INCREASINGLY highlighting a relationship between traumatic brain injury (TBI) and psychiatric disorders. Existing mental health or substance use problems elevate a person's risk of experiencing a TBI,^1,2 and individuals with a TBI are at heightened risk for developing novel psychiatric problems, including depression, anxiety, psychosis, and substance use disorders,³ suggesting there may be a significant number of persons with a history of TBI among mental health and addictions (MHA) service users. Unfortunately, due to gaps in care-seeking and follow-up for TBIs,^4–7 overlap in symptoms of TBI and psychiatric disorders,⁸ and poor integration between TBI and MHA service sectors,⁹ there may be significant underrecognition of TBI history among MHA service users. However, literature examining assessment and rates of TBI among individuals receiving MHA services has not, to our knowledge, been reviewed.

Individuals with a history of TBI are at risk for poorer mental health, but are also more likely to have comorbid physical health concerns, as well as cognitive challenges such as difficulties with memory or impulse control,^10–13 making TBIs a potential source of added complexity for persons seeking mental health care. Individuals with a psychiatric history are also at particular risk for experiencing the emotional, physical, and cognitive symptoms of TBI beyond the typical recovery period.¹⁴ Identifying a prior TBI as part of their assessment may help MHA clinicians better understand the etiology of their patients' presenting behaviors or symptoms. TBI has also been linked to increased risk for suicide, self-harm, violence, and victimization,^15–18 meaning that identifying prior injuries could be highly relevant to MHA clinicians' risk assessments and subsequent care planning. If clinicians understand the demographic and clinical predictors and outcomes of TBI among MHA service users, they may better be able to identify when screening is indicated. Again, however, the current extent of knowledge on this topic has not previously been described, creating barriers to understanding whether there are clinical features associated with TBI history among individuals accessing MHA care.

In this instance, a scoping review is recommended to identify and summarize the existing evidence as well as knowledge gaps where further research is needed.¹⁹ The purpose of this review is to understand: (a) the prevalence of TBI history among individuals accessing MHA services; (b) how TBI history has been identified within MHA service settings; and (c) what predictors or outcomes of TBI have been reported in these service settings.

METHODS

This scoping review was designed in compliance with the Preferred Reporting Items for Systematic Review and Meta-Analysis extension for Scoping Reviews (PRISMA-ScR).²⁰ The methods were guided by Levac et al's²¹ expansion on Arksey and O'Malley's²² methodological framework for conducting scoping reviews.

Stage 1: Identifying the research question

The research questions guiding this scoping review were:

1. How prevalent is a history of TBI among individuals of all ages who are accessing any type of MHA service?
2. What methods are used to identify a history of TBI within MHA service settings?
3. What predictors and outcomes of TBI have been reported in samples of individuals accessing MHA services?

Stage 2: Identifying relevant studies

The search strategy was initially developed in Medline in consultation with librarians experienced in mental health research. Key words and subject headings representing the concepts of TBI, MHA settings, and screening were developed, combined, and limited to human studies published in English (See Supplemental Table 1, available at: https://links.lww.com/JHTR/A537). The search was translated to CINAHL, EMBASE, PsycINFO, and SPORTDiscus. Results were pulled from the inception of each database up to the date of the search (April 16, 2020).

A gray literature search was also carried out using the Grey Matters Checklist, a structured tool for comprehensive gray literature searching.²³ Four Advanced Google Searches (limited to Canada, the United States, Australia, or the United Kingdom) were carried out using simplified key words. Potentially relevant documents from the first 50 results for each search were added to the Grey Matters search results for screening.²³

Following screening, the reference lists of included documents were also screened for additional relevant articles.

Stage 3: Study selection

Database search results were deduplicated and²⁴ then screened using Covidence.²⁵ Studies were included if they: (a) were written in English; (b) recruited participants of any age from MHA service settings; (c) had a primary aim of screening participants for TBI history; and (d) focused on a civilian population. Particularly high rates of blast-related injury and comorbid TBI and psychiatric disorders, as well as targeted efforts within Veterans Health systems for early identification and treatment of TBI and associated health problems,^26–28 suggest that veterans/military service members are a complex group not representative of the general population accessing MHA care, warranting separate study. Commentaries, case studies, and editorials were excluded, as the goal was to find empirical data answering the research questions. MHA settings were defined as any clinical service with a primary goal of providing MHA assessment, treatment, or resources.

To test the eligibility criteria, randomly selected results were independently screened by title and abstract in rounds of 50 by 2 reviewers (J.D. and C.D.). After each round, the reviewers discussed and refined the eligibility criteria as needed until more than 90% agreement was reached (after 3 rounds). Another random 10% of the database search results were then screened independently by both reviewers, maintaining this level of agreement. The remaining records were screened by one reviewer (J.D.). All records appearing to meet the eligibility criteria were independently assessed in full-text review by both J.D. and C.D.. The gray literature search results, not having abstracts, were imported into a Microsoft Excel file and independently assessed by full text for eligibility by J.D. and C.D. Any disagreements between screeners at any stage were resolved by discussion and consensus.

Stage 4: Charting the data

One reviewer (J.D.) extracted data for all the included documents, and a second (C.D.) extracted data for 5 randomly selected documents to ensure reliability of the extraction form, which was created in Microsoft Excel. Data for extraction included bibliographic information, study design, research questions, setting and sample descriptions, inclusion/exclusion criteria, TBI definition, screening method, prevalence and characteristics of reported TBIs (eg, severity of TBIs if reported), potential predictors/outcomes of TBI assessed, variables found to be associated with TBI history, analysis methods, psychometric testing of the screening tool, and future research recommendations.

Stage 5: Collating, summarizing, and reporting the results

Questions 1 and 2

The reported prevalence of TBI found in each sample, as well as methods used to assess TBI history, were collated in table format alongside other descriptors of the study (eg, design, sample, and setting). Prevalence of TBI was summarized as a percentage of participants identified as having a TBI history (either as reported in the study or by dividing the number of participants with TBI by study sample size). The number of studies using each type of TBI screening method was also summarized numerically.

Question 3

Variables which were examined for a potential relationship to TBI, including key demographics and broad clinical variables, by at least 2 studies were synthesized in table format, identifying the number of studies that did or did not find a relationship between the variable and TBI status based on their analysis. These were also synthesized narratively to review trends in the relationship between each variable and TBI status.

RESULTS

Sources of evidence

The search and screening results are presented in Figure 1. Twenty-seven journal articles and 2 dissertations were included in the review, describing 28 unique studies (1 study being reported by both a dissertation and journal article^29,30). Included documents were published between 1990 and 2018, originating from the United States (n = 23), Canada (n = 2), the United Kingdom (n = 2), New Zealand (n = 1), and Norway (n = 1). Studies were recruited from diverse inpatient, outpatient, and community-based programs described as psychiatry/mental health,^29–48 substance use,^49–53 concurrent disorders,^54,55 and forensic programs.^56,57 Only 3 studies focused on participants with a specific psychiatric diagnosis^35,38,46 and all but one⁵² included male and female participants. Most (n = 24) studies focused on primarily adult samples (mean age 30-44 years). Three studies recruited participants from MHA services specifically for children and adolescents (mean age 10-12 years).^31,42,43 One study recruited from geriatric psychiatry services (mean age 66 years).³⁸

Figure 1.: PRISMA flow diagram for study selection.

Question 1: Prevalence of TBI

The prevalence of TBI reported by the included studies is summarized in Table 1. TBI was operationalized heterogeneously between the included studies. For example, 10 studies included only head injuries resulting in loss of consciousness and/or requiring medical care,^{33,34,38,39,47–49,53,55} while others sought specifically mild TBIs.^41,46

TABLE 1 - Characteristics of included studies, screening methods, and prevalence of TBI history

Author	Study design	Country and MHA setting	MHA sample size, n	MHA sample characteristics (mean age ± SDa, sexb, diagnoses) If included, non-MHA comparison group characteristics (recruitment setting, sample size, mean age ± SD a, sex b )	Operationalization and assessment of TBI	TBI prevalence
Albicini et al31	Cross-sectional	New Zealand 3 child and adolescent mental health services	149	12 ± 4 y 47% female Various mental health concerns	Self-report Ohio State University TBI Identification Method Short Form	28.3%
Burg et al32	Retrospective chart review	USA Inpatient psychiatry unit	100	35 ± 11 y 51% female Various diagnoses; psychotic and mood disorders most common	Self-report Head injury questionnaire unique to organization Injury with LOC or dazed	68%
Burg)30 Burg et al29	Cross-sectional	USA Inpatient psychiatry unit	74	Age and sex reported by TBI status TBI-positive (n = 49) 35 ± 10 y 51% female TBI-negative (n = 25) 32 ± 11 y 80% female Various diagnoses; depressive disorder most common	Self-report Head injury questionnaire unique to organization TBI with LOC or became dazed or dizzy	66%
Colantonio et al56	Retrospective chart review	Canada Forensic program at a single center: 6 inpatient units and 1 outpatient service	394	40 y 16% female Various diagnoses; schizophrenia and SUD most common	Clinical chart audit Head injuries with and without LOC	22.6%
Corrigan and Deutschle55	Prospective cohort	USA Community mental health center programs for co-occurring SUD and mental illness	50	38 ± 10 y 38% female Various concurrent mental and substance use disorders	Self-report Single-item question Injury to head that resulted in LOC or going to hospital	72%
Dinn et al33	Cross-sectional	USA Neuropsychology service with referrals from inpatient psychiatry	63	37 ± 10 y 7% female Various diagnoses; schizophrenia and psychotic disorders most common with high-comorbid SUD	Self-report Questions embedded within interview Closed head injury with LOC	NR
Doherty et al34	Cross-sectional	United Kingdom Service for refugees with trauma-related mental health problems	103	36 ± 9 y 59% female Diagnoses NR	Self-report Customized intake screening questionnaire Head injury with LOC	51%
Drange et al35	Cross-sectional	Norway 17 psychiatric hospitals and outpatient clinics	505	42 ± 14 y 57% female All bipolar disorder or cyclothymia	Self-report Questions embedded in admission questionnaire Medically diagnosed TBI prior to age of bipolar disorder onset only, with or without LOC	7.3%
Felde et al53	Cross-sectional	USA University alcohol-drug program	550	Sex and age reported by TBI status TBI-positive (n = 218) 30 ± 9 y 61% men, 39% women Various psychiatric and/or SUD diagnoses TBI-negative (n = 332) 32 ± 11 y 50% men, 50% women Various psychiatric and/or SUD diagnoses among whole sample	Self-report Single-item question Head injury acquired during adulthood, which resulted in LOC	39.6%
Fox et al36	Cross-sectional	USA Outpatient psychological treatment	400	38 ±14 y 55% female, 9% unknown sex Diagnoses NR	Self-report Question embedded within symptoms checklist Asked whether knocked unconscious or bumped head within past 2 y only	3.5% knocked unconscious 9.3% bumped head
Gargaro et al37	Cross-sectional	Canada Assertive community treatment team for homeless persons	48	43 ±13 y 31% female Various diagnoses, primarily schizophrenia and other psychosis	Self-report Ohio State University TBI Identification Method Short Form	56%
Graves et al38	Case-control	USA 2 geriatric psychiatry clinics (1 academic hospital, 1 Veterans Affairs Center)	130	Cases 66 y 46% female Alzheimer's diagnosis Nonclinical controls recruited from MHA patients' nonbiological relatives and friends n = 130 64 y 46% female (matched by sex to cases)	Surrogate respondent (eg, spouse) report Head injury resulting in physician/hospital care or LOC	MHA cases: 23.9% Nonclinical controls: 8.5%
Hawley and Maden57	Retrospective chart review	United Kingdom 5 medium-secure inpatient units	113	36 ± 13 y 18% female Various diagnoses, primarily psychosis/schizophrenia	Clinical chart audit Previous head injury	41.6%
Holtzer et al39	Mixed prospective cohort and retrospective chart review	USA 3 acute inpatient psychiatry units	46	61% female Mood, anxiety, and adjustment disorders Age reported by TBI status Confirmed TBI: 38 ± 8 y Unconfirmed TBI: 37 ± 17 y TBI-negative: 36 ± 11 y	Self-report Traumatic Brain Injury Questionnaire TBI with LOC of at least 1 min Reported TBIs confirmed through record review or eyewitness interviews where possible	Reported and confirmed 32.6% Reported but not confirmed 28.3%
Hux et al40	Cross-sectional	USA Community-based mental health referral service	69	35 y 49% female Primary diagnosis not reported Non-MHA comparison groups recruited from vocational rehabilitation service, homeless shelter, and domestic abuse facility Vocational rehabilitation n = 1648 36 y 49% female Homeless shelter n = 240 36 y 86% female Domestic abuse facility n = 42 30 y 100% female	Self-report HELPS screening tool Positive screen for TBI requires all of (a) injury to head, (b) LOC/altered consciousness or medical assessment, and (c) ≥2 injury-related chronic problems	Mental health service group: 58.0% Vocational rehabilitation group: 25.6% Homeless shelter group: 19.6% Domestic abuse center group: 52.8%
Malloy et al51	Cross-sectional	USA Outpatient alcohol treatment program at private psychiatric hospital	60	NR for entire screened sample	Self-report Inventory of injuries Head injury with LOC, hospitalization, or major neurologic alterations	NR
Mateo et al41	Mixed prospective cohort and retrospective chart review	USA Inpatient psychiatric unit	106	Reported by TBI status mTBI group (n = 54) 35 y 50% female Mixed psychiatric diagnoses, primarily affective disorders Matched no TBI group (n = 52) 34 y 50% female Matched on diagnostic category	Screened on admission—not specified Mild TBI only based on American Congress of Rehabilitation Medicine criteria: head trauma with one of (a) LOC <30 min, (b) GCS ≥ 13, (c) altered mental acuity, and (d) focal neurologic signs	NR
Max and Dunisch42	Retrospective chart review	USA Child and adolescent outpatient psychiatric clinic	1333 screened Final n = 148	NR for entire screened sample, reported only for TBI-positive group and matched controls (n = 148)	Clinical chart audit “Definite TBI”: head injury with one of the following: LOC, postconcussive symptoms, skull fracture, decreased functioning, CT scan, surgical intervention, or hospitalization; or recorded as “concussion” or “closed head injury” “Possible TBI”: other head or facial injuries recorded without the above details, history of seizure-related fall, head-banging, or physical abuse, or when recorded information from one source was contradictory	Definite TBI: 5.6% Possible TBI: 15.5%
Max et al43	Retrospective chart review	USA Inpatient child psychiatry unit	694 screened Final n = 112	NR for entire screened sample, reported only for TBI-positive group and matched controls (n = 112)		Definite TBI: 8.1% Possible TBI: 24.5%
McGuire et al44	Cross-sectional	USA 2 inpatient and 2 outpatient mental health programs	231	37 ± 12 y 49% female Primary diagnoses NR Non-MHA comparison group recruited from a medical clinic and from university and hospital staff and students Medical clinic patients n = 59 40 ± 16 y 54% female University/hospital staff/students n = 534 35 ± 14 y 70% female	Self-report Traumatic Brain Injury Questionnaire Injury where hit head with LOC	MHA group: 33% Medical clinic patients: 19% Hospital and university staff and students: 13%
McHugo et al54	Cross-sectional	USA Integrated treatment program for concurrent disorders within an urban mental health agency	295	44 ± 9 y 61% female All concurrent SUD and mental illness	Self-report Ohio State University TBI Identification Method	80.3%
Murrey et al45	Retrospective chart review	USA 7 inpatient psychiatric programs	3133	82% between ages of 18 and 62 60% men Primary diagnosis NR	Clinical chart audit Documented history of TBI	16.7%
Murrey et al52	Cross-sectional	USA Substance use treatment program	2198	31 y (range 16-80) 100% female Primary SUD diagnosis NR	Self-report Questionnaire (not specified) Head trauma with change in/loss of consciousness	42.3%
Poppe46	Cross-sectional	USA 1 inpatient and 1 outpatient psychiatry program	60	Reported by TBI status mTBI group (n = 34) 39 ± 10 y 59% female No TBI group (n = 26) 37 ± 12 y 73% female All diagnosed with major depression	Self-report Questionnaire to screen for mTBI created from American Congress of Rehabilitation Medicine criteria	56.7%
Sacks et al50	Cross-sectional	USA 27 addiction treatment programs (inpatient, outpatient, transitional living, methadone maintenance)	845	35 ± 10 y 21% female Primary diagnoses NR	Self-report Brain Injury Screening Questionnaire	NR
Salloum et al47	Mixed prospective cohort and retrospective chart review	USA Community mental health center (outpatient, day treatment, and family system programs)	56	Age range 21-69 39% female Various psychiatric diagnoses	Self-report Screening form Head injury resulting in LOC	NR
Schneeberger et al48	Cross-sectional	USA 7 outpatient psychiatry clinics	183	Age NR 39% women; 61% men Various psychotic and mood disorders	Self-report Single-item question Traumatic head injury with LOC	19.7%
Walker et al49	Cross-sectional	USA Substance abuse programs including outpatient, case management, and residential	7784	65% men Primary diagnoses NR Age reported by TBI status No TBI: 33 y 1 TBI: 34 y 2+ TBI: 34 y	Self-report Single-item question Lifetime head injuries resulting in LOC or hospitalized at least 1 night	31.7%

Abbreviations: GCS, Glasgow coma scale; LOC, loss of consciousness; MHA, mental health and addictions; NR, not reported; SUD, substance use disorder; TBI, traumatic brain injury.

^aFigures presented are rounded to nearest whole number from reported figures for consistency between studies.

^bSex presented as percentage female; when sex not reported, all reported genders presented.

Among studies reporting total lifetime history of TBI (n = 20), prevalence ranged from approximately: 6% to 28% in pediatric settings; 32% to 59% in services focused primarily on substance use; and 17% to 58% in settings described as psychiatry/mental health services in primarily adult samples. Two studies recruited from services for concurrent psychiatric and substance use disorders and reported lifetime TBI history prevalence of 72%⁵⁵ and 80%.⁵⁴ Two studies assessed patients in forensic services and found lifetime TBI prevalence of 23%⁵⁶ and 42%.⁵⁷ Three studies^38,40,44 made comparisons between MHA service users and other groups, and all found the MHA service user samples had a higher rate of prior TBI.

Question 2: Screening methods

TBI history was assessed by self-report (n = 21), surrogate report (n = 1), or retrospective chart audit (n = 5), while 1 study did not identify their assessment method⁴¹ (see Table). Among the studies reporting on lifetime TBI history, self/surrogate-report and chart audits identified prevalence ranging from 24% to 80% and 6% to 42%, respectively. Self-report screening methods were not always described in detail, but studies reported using 1- or 2-item questions as well as longer structured questionnaires.

Question 3: Predictors and outcomes of TBI history

Twenty-two studies examined whether certain variables were associated with TBI (see Supplemental Table 2, available at: https://links.lww.com/JHTR/A538). Twelve studies used bivariate analyses (eg, t tests or χ² tests) to establish an association between TBI and other variables,^{31,34,37,42–44,47,50,54–57} while 10 studies included multivariable analyses to establish a relationship between variables and TBI history.^{29,30,33,35,36,38,39,41,46,49,53}

Demographic variables

Eleven studies reported on sex or gender and TBI status. Gender was not clearly defined and was reported as man/woman or male/female, thus appearing to be conflated with biological sex. Among 5 studies finding a relationship between TBI history and sex/gender, male participants were consistently found to have a higher prevalence of TBI.^{29,30,34,49,53,56}

Two studies reported on the association between race and TBI, and 3 on ethnicity. One study reported that participants with a TBI were more likely to be White than African American,⁴⁹ and another that there was a greater proportion of Caucasians among participants with mild TBI compared an uninjured control group.⁴¹

Clinical variables

Eight clinical variables were examined by at least 2 studies for association with TBI history (see Supplemental Table 2, available at: https://links.lww.com/JHTR/A538).

Psychiatric diagnosis

Ten studies examined diagnostic categories in relation to TBI history.^{29–31,42,43,47,53–57} Diagnostic conceptualizations varied between studies (eg, using different editions of the Diagnostic and Statistical Manual of Mental Disorders). Presence or increased severity of TBI was associated with increased likelihood of having a personality disorder diagnosis in 3 studies.^54–56 In 1 pediatric sample, TBI history was linked to increased likelihood of communication disorders, but decreased likelihood of developmental disorders such as autism.⁴²

Mental health symptoms

Seven studies assessed the severity of participants' mental health symptoms.^{29–31,35,37,39,49,53} Four studies used various structured scales for symptom assessment^{29,30,35,39,53} and 3 used unstructured methods.^31,37,49 Five studies found that TBI status was associated with more severe mental health symptoms^{29,30,37,39,49,53} (such as increased psychological distress^29,30 or depression scale scores^39,53), while 2 found no relationship.^31,35

Substance use

Eleven studies assessed indicators of substance use severity including the number of days or months of recent substance use^49,54 or use of multiple substances,³⁷ structured scale score,⁵³ age of initial substance use,^50,55 whether participants have historically used substances,³⁹ or presence of previous or current substance use problems.^{29–31,46,57} Nine studies reported that TBI history increased the measured indicators of substance use severity^{29,30,37,39,46,49,50,53–55} while the other 2 studies reported no relationship.^31,57

Physical health concerns

Nine studies reported on physical health concern variables including previous contact with the medical care system,^42,43,46 presence of current physical symptoms,^35,36,55 or history of other injuries or medical disorders.^31,34,53,55 Two found that TBI history was linked to current symptoms including migraines³⁵ or dizziness, numbness, and tremors.³⁶ Another 2 studies found that history of TBI was associated with a history of other injuries (eg, fractures)⁵³ or contact with a neurologist,⁴⁶ while 5 found no relationship.^{31,34,42,43,55}

Functioning

Of 3 studies assessing functioning, 2 found no link between TBI history and functioning based on different scales, which measured participants' abilities to meet elements of functioning such as personal care, social, and occupational demands.^41,47 One study measured current functioning (rated by clinical staff following treatment completion or when the program grant ended),⁵⁵ finding that service users with TBI were over 3 times more likely to be judged as having deteriorated or ongoing unstable functioning.

Cognition and learning

This variable was assessed in different ways by 12 studies, including formal neuropsychological test batteries,^{29,30,39,46,51} clinically recorded indicators such as IQ or use of special education services,^31,42,43 and self-reported difficulties with cognitive function or school/learning.^{36,37,46,53,55} Seven studies reported that TBI status was associated with challenges including recent difficulty with understanding, concentrating, and remembering,^37,49 word-finding problems,³⁶ academic challenges,^46,53 or worse performance on one or more neuropsychological tests.^29,30,39 Four studies found no relationship,^31,43,51,55 and, notably, 1 reported no difference in cognition variables between participants with and without TBI history of any severity, but found that participants with mild TBI history only had slightly higher performance IQ than participants with no TBI.⁴²

Risk to self

Six studies assessed variables related to suicidal ideation, self-harm, or previous suicide attempts,^{31,35,37,49,53,57} 4 of which found no relationship with TBI history.^31,35,37,53 One study found that service users with a history of TBI were more likely to have had suicidal thoughts or a suicide attempt in the past 12 months.⁴⁹ Another found that while service users with a TBI did not have a higher rate of previous self-harm problems, clinicians were more likely to consider them being at risk of harm to self.⁵⁷

Risk to others

Six studies assessed and found a link between TBI history and increased hostility,⁴⁷ difficulty controlling violent behavior,^37,49 or a history of violence or aggression toward others.^33,54,57 Of note, one study⁴⁷ found that TBI increased hostility scores among female participants only when the injury required medical care, and another³³ found that the relationship between TBI history and violence became insignificant after controlling for substance use.

DISCUSSION

This scoping review identified that nearly three-quarters of studies reporting on lifetime TBI found that more than 25% of MHA services users had a history of self-reported or documented TBI, and nearly half of them found rates over 50%. A 2013 meta-analysis reported a 12% prevalence of lifetime TBI among adults in the general populations of high-income countries.⁵⁸ Since then, other studies of general populations have found prevalence rates ranging from 13% up to 43%,^5,59–62 suggesting an overrepresentation of individuals with prior TBI in many MHA settings compared with nonclinical populations. Comparison across settings is, however, extremely difficult given the high variability in operationalization of TBI across the available literature. This has been noted as a challenge in other reviews, which have assessed TBI prevalence in special populations such as offenders or individuals experiencing homelessness.^63,64 Use of a standardized definition of TBI is needed in ongoing research to compare findings across populations of interest.

Within this review, the studies using chart audits to assess TBI history generally reported lower prevalence than those utilizing self-report methods. Available literature suggests that approximately 20% to 30% of individuals experiencing a TBI do not seek any medical assessment or care for their injury, particularly for milder injuries.^4,5,65,66 Relying on medical documentation alone could thus result in considerable underreporting of previous injuries. This issue may be exacerbated among individuals with psychiatric disorders, who face significant barriers to accessing physical health care.⁶⁷ Structured self-report questionnaires are currently considered best practice for assessing a history of TBI,⁶⁸ and MHA clinicians should consider using these during assessments instead of relying on medical charts for injury history. This scoping review identified structured tools that could be used to screen for TBI among MHA service users. These measures are thought to be more accurate than single-item questions for capturing past injuries,⁶⁹ although rates of TBI appear to be comparable between the studies using single questions and those using more structured methods in this review.

The diversity in TBI definition and assessment methods may also have contributed to the inconsistent findings regarding the relationship between TBI history and several of the examined clinical variables. However, some trends were identified. For example, history of TBI was consistently linked to increased indicators of aggression or hostility. This finding aligns with research suggesting that TBI prevalence is disproportionately high among offender populations⁶³ and that TBI increases the risk of engaging in violent crimes.⁷⁰ MHA clinicians may thus consider screening patients for TBI history, as it could be relevant to their understanding of the etiology of aggressive behaviors, their formulation of risk level, and subsequent treatment planning. TBI was also frequently linked to indicators of more severe or risky substance use. As individuals with moderate or severe TBI are 10 times more likely to die of unintentional poisoning than the general population,⁷¹ identifying history and consequences of TBI may also help MHA clinicians make decisions with their patients about prescribing and monitoring commonly used psychiatric medications with increased potential for addiction, such as benzodiazepines. Cognitive consequences of brain damage such as impaired decision-making and reduced self-awareness have been speculated to make it more difficult for patients to successfully engage in addiction treatment.^72,73 Interestingly, cognitive challenges were not consistently associated with prior TBI in this review, but there was evidence that subjective difficulties with functions such as remembering or concentrating were more likely to be a problem for patients with TBI. Cognitive impairments are already common features of many psychiatric disorders,⁷⁴ but TBI-related deficits in planning, memory, or decision-making could warrant modifications to treatment modalities that require increased cognitive engagement such as cognitive behavioral therapy, though robust assessment of modified interventions has been limited thus far.⁷⁵ Future research using structured TBI history assessments may establish whether there are specific TBI-linked symptom clusters experienced by MHA service users, such as difficulties with aggression, higher-risk substance use, or cognitive challenges. This understanding will provide opportunities to develop and evaluate targeted MHA care plans for individuals with a TBI history, who are currently at high risk for service gaps.⁹

This review highlighted some significant limitations to the current body of knowledge in this topic. First, the cross-sectional and chart review methods used in most of the included studies reduce clarity on the direction of the relationship between TBI and examined clinical variables. Prospective longitudinal studies incorporating TBI identification at treatment entry are needed to identify clinical and service use outcomes of TBI history across a MHA service use trajectory, further identifying opportunities for targeted care.

Also, this review found that males were often more likely to have a TBI history, in alignment with findings in the general population.⁷⁶ However, sex and gender were often poorly defined in the included studies. Clearly delineating and examining both sex and gender as separate variables is important, as both may have unique roles in the emotional or behavioral impacts of TBI.⁷⁷

Finally, only 3 studies were conducted in pediatric settings, with a mean participant age of 10 to 12 years.^31,42,43 As adolescents 13 years and older are presenting to healthcare settings for TBI at a rapidly increasing rate,^78,79 and adolescence and emerging adulthood represent the peak age of onset for most mental illnesses,^80–82 further exploration of TBI among youth MHA service users is warranted. Additionally, only one study assessed TBI in an older adult sample,³⁸ which, given the particularly high risk for falls among older MHA service users,⁸³ represents a significant gap in the current literature.

Limitations

This scoping review included an extensive search of academic and gray literature. However, as we aimed to include studies with a primary focus of screening for TBI in MHA settings, some studies, which included TBI among several variables of interest, may have been excluded. The inclusion criteria would have also resulted in the exclusion of qualitative studies, which could provide in-depth understanding of MHA service user experiences of TBI screening and outcomes, and studies not published in English. Finally, while methodological limitations of the current body of evidence were discussed, we did not conduct a formal critical appraisal of each study. While this is not a necessary step in scoping reviews, it may have helped further explore current knowledge gaps.

CONCLUSION

This scoping review identified a relatively high prevalence of prior TBI among individuals using MHA services. Screening for TBI in these settings may provide insight into behaviors or ability to engage with care. Continued research with a focus on prospective studies and use of consistent screening methods for TBI across settings will allow better understanding of the relationship between TBI and clinical profiles and outcomes.