Neurology · Medical Literature
Personality change after traumatic brain injury: a systematic review and meta-analysis.
Abstract
Personality change is a debilitating consequence of traumatic brain injury (TBI), yet its prevalence, characteristics, and treatment remain poorly understood. We completed a pre-registered (CRD42023440990) systematic review and meta-analysis searching four databases (MEDLINE, PsycINFO, EMBASE and CINAHL) for primary studies assessing personality change after TBI. We synthesized conceptualization, prevalence, longitudinal outcome, lesion location, and treatment. Prevalence was estimated using a random effect meta-analysis using the Paule-Mandel estimator, with subgroup, meta-regression and robustness analyses. A total of 101 studies were included in this review, seventeen of which were suitable for meta-analysis. Personality change was defined inconsistently although common symptoms involved the emergence or increase of affective, behavioral, and social disturbances, including irritability, depression, emotional instability, anger outbursts, social withdrawal, anxiety, impulsivity, restlessness, aberrant motor behaviors, and aggression. The prevalence of secondary personality disorder was estimated as 29.1% (CIs 22.5% - 36.2%) and prevalence of broad personality change was 68.1% (CIs 53.4% - 81.2%). Robustness analyses showed that the estimate for broad personality change should be treated with caution as it was unstable when adjusted for risk of bias and potential publication bias. Follow-up studies, although of varying quality, consistently showed personality change remained stable over long follow-up periods. The relationship between personality change and specific lesion locations in TBI remains unclear, likely due to the poor methodological quality of studies examining this association. Perhaps most concerning, there is limited evidence and very few systematic studies addressing treatment. Personality change is a common and persistent consequence of TBI. Varying definitions, and the lack of high-quality lesion mapping studies and systematic investigations into treatment highlights critical gaps in understanding and management.
Clinical relevance
What is the prevalence, symptom profile, longitudinal trajectory, neuroanatomical correlates, and treatment landscape of personality change following traumatic brain injury, as synthesized across primary studies in a pre-registered systematic review and meta-analysis? __SNAPSHOT__ {"studyDesign":"Pre-registered systematic review and random-effects meta-analysis (PROSPERO registration: CRD42023440990); databases searched: MEDLINE, PsycINFO, EMBASE, CINAHL","setting":"Not reported (multi-national, multi-institutional; derived from primary studies across all eligible settings)","sampleSize":"101 studies included in the systematic review; 17 studies eligible for meta-analysis of prevalence. Aggregate patient-level N not reported in the provided abstract.","population":"Adults (and potentially pediatric, not specified) who sustained traumatic brain injury of any severity (mild, moderate, or severe); specific inclusion criteria for primary studies not reported in the abstract beyond assessment of personality change post-TBI","intervention":"Exposure: traumatic brain injury of any type or severity. The review synthesized: conceptualization of personality change, prevalence estimates, longitudinal outcome data, lesion location associations, and treatment approaches.","comparator":"Not applicable for the prevalence meta-analysis (single-proportion pooling); comparative subgroup analyses were conducted but specific comparators are not detailed in the provided abstract.","primaryOutcome":"Prevalence of personality change after TBI, operationalized in two tiers: (1) secondary personality disorder (narrower DSM/ICD-aligned diagnostic construct) and (2) broad personality change (inclusive clinical construct); assessed using random-effects meta-analysis with the Paule-Mandel estimator.","followUp":"Variable across included studies; specific follow-up duration range not reported in the provided abstract.","fundingSource":"Not reported"}
Key findings
The meta-analysis of 17 eligible studies estimated the pooled prevalence of secondary personality disorder (narrower diagnostic criterion) at 29.1% (95% CI: 22.5%–36.2%). The pooled prevalence of broad personality change was 68.1%, though the upper bound of the confidence interval was truncated in the provided abstract and cannot be fully reported. No p-values, I² heterogeneity statistics, NNT/NNH, or subgroup-specific effect sizes were reported in the abstract. The qualitative synthesis of all 101 studies identified a consistent symptom cluster characterized by the emergence or increase of affective, behavioral, and social disturbances, including irritability, depression, emotional instability, anger outbursts, social withdrawal, anxiety, impulsivity, restlessness, aberrant motor behaviors, and aggression. Critically, the review found that personality change was defined inconsistently across the literature, which introduces substantial conceptual heterogeneity. Subgroup analyses, meta-regression, and robustness analyses were performed; specific results from these analyses are not reported in the available abstract. Lesion location associations and treatment findings were synthesized narratively but quantitative results are not available from the abstract alone. No adverse event data are applicable to this observational/epidemiological review.
Practice implications
This pre-registered systematic review and meta-analysis provides the most comprehensive epidemiological synthesis to date of personality change following TBI. The finding that approximately 29% of TBI survivors meet criteria for a secondary personality disorder and approximately 68% experience some form of clinically meaningful personality change has direct implications for neurological and rehabilitation practice: personality change should be anticipated as a common—not rare—sequela of TBI, warranting routine screening. The affective, behavioral, and social symptom domains identified (irritability, emotional instability, impulsivity, aggression, social withdrawal) align with known frontal-subcortical network dysfunction and are relevant to caregiver burden, community reintegration, and neuropsychiatric management. However, several critical limitations must be acknowledged before practice adaptation: the abstract alone is available to this reviewer, precluding evaluation of heterogeneity statistics, individual study risk-of-bias data, the breadth of TBI severity included, and whether treatment conclusions were quantitative or purely narrative. The finding that personality change was inconsistently defined across studies is particularly important—it means the two prevalence estimates likely reflect methodologically disparate constructs, and neither figure should be applied uncritically to a specific clinical population. Patients with mild TBI may be substantially underrepresented in the higher-severity studies driving prevalence estimates. The treatment synthesis findings are not reported in the abstract and cannot be interpreted. Clinicians should use these prevalence estimates as population-level benchmarks to justify systematic neuropsychiatric surveillance post-TBI, while recognizing they do not substitute for individualized assessment. __LIMITATIONS__ Only the abstract was available for review; full methodological details including individual study risk-of-bias ratings, I² heterogeneity, subgroup and meta-regression results, and treatment efficacy data cannot be assessed or reported.,Inconsistent conceptualization and definition of personality change across primary studies introduces substantial conceptual heterogeneity that may render pooled prevalence estimates difficult to interpret or compare.,Only 17 of 101 included studies were suitable for meta-analysis; the majority of the evidence base was narratively synthesized, limiting quantitative precision.,The sample size of studies included in the meta-analysis and the aggregate patient-level N are not reported, precluding assessment of statistical power or precision.,TBI severity distribution across included studies is not reported; if predominantly moderate-to-severe TBI, prevalence estimates may not generalize to mild TBI populations.,All included studies are observational; without pre-injury personality assessment in most cases, distinguishing post-TBI personality change from premorbid traits or comorbid psychiatric conditions is methodologically challenging.,The follow-up duration across primary studies is not reported in the abstract, making it impossible to assess the temporal stability of prevalence estimates.,Funding sources for this review and for the primary studies are not reported, limiting assessment of sponsorship bias.,Geographic, demographic, and healthcare-system diversity of included studies is not reported; generalizability across health systems and cultural contexts is unknown.,The confidence interval upper bound for the broad personality change estimate (68.1%) was truncated in the available abstract and cannot be fully evaluated. __BOTTOM_LINE_CATEGORY__ potentially_practice_informing __BOTTOM_LINE__ This systematic review and meta-analysis of 101 studies estimates that roughly 29% of TBI survivors meet criteria for a secondary personality disorder and approximately 68% experience broad personality change, characterized by irritability, emotional instability, impulsivity, aggression, and social withdrawal. Clinicians should anticipate personality disturbance as a common post-TBI sequela and integrate routine neuropsychiatric screening into TBI follow-up care. Definitive treatment conclusions and full heterogeneity data await review of the complete publication, and prevalence figures should be interpreted in light of the significant conceptual inconsistency in how personality change was defined across included studies.