Is There a Connection Between Mild TBI and Mental Health Disorders in Adults and Children?

In a previous study of mTBI, we found that mTBI was associated with a significantly increased risk of having subsequent affective disorders. These disorders were most prominent during the first 12 months (23% following mTBI and 14% in the control group).

[Delmonico RL, Theodore BR, Sandel ME, Armstrong MA, Camicia M. Prevalence of depression and anxiety disorders following mild traumatic brain injury. PM&R. 2022 Jul;14(7):753-763. doi: 10.1002/pmrj.1265]).

In our previous study, 42% of patients with an mTBI diagnosis were under 18. We made it a priority to investigate the pediatric population as our next step in our research. From an extensive review of the literature, it was clear that the predominant mental health disorders in children and adolescents were affective disorders (depressive, anxiety, and adjustment disorders) and behavioral disorders (oppositional defiant disorder (ODD), attention deficit hyperactivity disorder (ADHD), and conduct disorder.

We conducted a study within the integrated healthcare system of Kaiser Permanente Northern California (KPNC), where a total of 18,917 pediatric patients ranging from 0 to 17 years of age were diagnosed with an mTBI between January 1^, 2000 to December 31, 2014. This mTBI group was compared to a matched comparison group that included two mTBI-unexposed pediatric patients (N = 37,834) per each mTBI-exposed patient, randomly selected and matched for age, sex, race/ethnicity, and date of medical visit at KPNC corresponding to when mTBI was diagnosed in the exposure group (reference date).

The primary outcomes were diagnoses of affective (depressive, anxiety, or adjustment) or behavioral disorders (conduct, oppositional defiant, attention deficit and hyperactivity)

[International Classification of Disease, Tenth Revision, Clinical Modification (ICD-10-CM), or the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V),110] in the 4 years after mTBI or the reference date of the comparison group.

We first identified all pediatric patients (17 and younger at the time of encounter) seen in our integrated healthcare system between 2001 and 2014. This included those seen at emergency departments, urgent care clinics, and outpatient clinics. At this point, we then identified all those who received a primary diagnosis for mTBI during that healthcare encounter and classified them as the mTBI pool, while the remaining patients were classified into a control group. We then proceeded to exclude those who:

1. had lapsed healthcare plan coverage (< 9 months in any 12-month period) during the study observation period (including the 4-year post-injury follow-up);
2. had any associated diagnoses for moderate to severe brain injuries at any time prior to or during the study observation period (including the 4-year post-injury follow-up);
3. were deceased anytime during the study observation period (including the 4-year post-injury follow-up); and
4. were in the mTBI pool but received the diagnosis for mTBI outside our integrated healthcare system and who had no follow-up healthcare encounter within 7 days of that externally-established diagnosis.

These criteria were established to ensure that the patients in both groups could be compared in a valid manner based on a complete set of data, that there were no confounding factors related to prior or subsequent brain injuries more severe than a mTBI, and that there were no confounding factors for healthcare encounters occurring outside our integrated healthcare system for which we may have minimal detailed records about symptom management and treatment.

The final pools of patients were then matched on demographic factors, resulting in a mTBI group and a non-injured control group. We then reported incidence rates (i.e., new psychological disorders occurring post-injury) and calculated adjusted risk ratios to compare the effect of mTBI on post-injury mood and behavioral disorders, compared to non-injured controls.

Our results indicated that adjusted risks for affective disorders were significantly higher across the first 3 years post-injury for the mTBI group and was also most prominent during the second year with a 34% increase in risk, relative to the comparison group.

The age group with the highest risk for post-injury affective and behavioral disorders was 10- to 13-year-olds, followed by those aged 14- to 17-years-old. Adjusted risks for behavioral disorders were significant at years 2 and 4 with up to a 37% increase in risk, relative to the comparison group. These risks for post-mTBI behavioral disorders were only significant in the 10- to 13-year-old age group.

The consistency of the findings among the 10- to 13-year-old and the 14- to 17-year-old groups was very striking. The disorders emerge and peak within the first 2 years consistently in these age groups. We were surprised because we expected to see more variability in the disorders among the age groups and time periods.

We were also quite surprised, and concerned, that there was a relatively high incidence of mood disorders among the non-injured control group. However, we cannot make any statements to what is driving these higher rates. This will require further research with a different study design.

The most important point is that the 10- to 13-year-olds were at the highest risk for developing a new affective or behavioral disorder following a concussion/mild TBI and the 14- to 17-year-olds also at significant risk for an affective disorder following an injury.

Children and adolescents who have sustained a mTBI should be screened for these disorders initially and through ongoing assessments for up to at least 2 years post-injury and ideally up to 4 years post-injury. Although all pediatric mTBI patients should be included in these assessments, they are particularly important in the 10- to 17-year-olds. The assessment measures are available online and at no cost, and they should include at a minimum the Pediatric Outcomes Questionnaire (POQ). These assessments can be sent to parents on regular intervals through an electronic medical record app or email. In addition, questions regarding emotional and behavioral changes should be included in all pediatric medical visits with special attention to all patients who have previously sustained a mTBI.

Although our findings did not demonstrate a clear increased risk for infants and toddlers, they are equally at risk for developing emotional and behavioral changes which our studies may not have detected due to our reliance on psychiatric diagnoses. This could be due to a general reluctance of providers to give children under 5 years old a psychiatric diagnosis unless there is a developmental disorder that will need to be addressed over a longer period of time.

The most important point is that 10- to 13-year-olds were at the highest risk for developing a new affective or behavioral disorder following a concussion/mild TBI and the 14- to 17-year-olds also at significant risk for an affective disorder following an injury.

These results highlight the importance of regular interval screening for affective and behavioral disorders in children who sustain a mild TBI over at least 2 years post injury.

We actually just concluded a study investigating the impact of the COVID-19 pandemic era on children who sustained a mTBI just prior to or during the pandemic, with the aim of determining the impact the pandemic had on the development of psychological disorders and related healthcare utilization for treating those with these diagnoses. With school closures, remote learning, lack of social contact and the general stress related to pandemic restrictions, our hypothesis was that the incidence of mood and behavioral disorders would be significantly higher than our historical rates observed in the present study.

Our data on this are going through final analysis in preparation for submission to a peer-reviewed medical journal.  It will be also be important to start considering studies focused on implementation science that are designed for early identification of risks that can be addressed before it becomes a chronic psychological disorder.