The Prevalence of Traumatic Brain Injury (TBI) Among People Impacted by the Criminal Legal System: An Updated Meta-Analysis and Subgroup Analyses

Objective: Traumatic brain injury (TBI) is a significant public health concern and has implications for people directly impacted by the criminal legal system during arrest, conviction, incarceration, and community supervision. This meta-analysis estimated the lifetime prevalence of TBI among people supervised by the criminal legal system across settings. Hypotheses: Building on previous research, we hypothesized that prevalence estimates would be impacted by methodological, clinical, and demographic factors. Method: Eligible studies included those with adult participants supervised by the criminal legal system (i.e., prison, jail, probation, parole, inpatient/forensic hospital) and that provided sample TBI prevalence and method of ascertaining TBI history. We employed subgroup analyses and metaregression to investigate the effects of setting, TBI definition and method of detection, lifetime history of mental illness and substance use disorders, and gender. Results: The sample ultimately included 64 studies totaling 52,540 participants. Using a random-effects model and logit transformation, we found that the overall estimate of TBI prevalence was 45.8% (95% confidence interval, CI [37.8, 54.1], 95% prediction interval, PI [5.5, 92.5]) across all studies and 32.0% (95% CI [25.0, 39.8], 95% PI [11.2, 63.6]) for moderate-to-severe TBI. Significant effects were found for TBI definition and method of detection on the pooled estimate. Conclusions: The prevalence of TBI among people impacted by the criminal legal system may be larger than in the general population. However, despite recent and ongoing progress in this area of study, the reliability of prevalence estimates remains limited by methodological factors related to TBI definitions and detection methods. Implications for TBI research and clinical service provision are discussed. Public Significance Statement This study estimated high rates of lifetime traumatic brain injury (TBI) history among people impacted by the criminal legal system. We also found that TBI rates significantly differ depending on how researchers define and measure TBI. These findings emphasize the importance of standardized TBI research methods and support the need for increased TBI screening procedures for individuals in criminal legal settings.