Development of Psychiatric Disorders after Mild Head Trauma according to Birth History

1. Study design and population

This retrospective cohort study reviewed medical records of pediatric patients under 18 years of age who presented with head trauma at Wonju Severance Christian Hospital from January 1 through December 31, 2013. The study was approved by the Institutional Review Board of Wonju Severance Christian Hospital, Yonsei University Wonju College of Medicine (IRB No. CR324125). Written informed consent by the patients was waived due to a retrospective nature of our study.

The year 2013 was selected for the chart review as it marked the implementation of electronic medical records at the institution. This approach permitted a full 10-year follow-up period extending to 2023, ensuring consistent and high-quality data. Including records from prior years could have compromised data reliability due to the absence of standardized electronic records. Psychiatric diagnoses were tracked for 10 years following head trauma using data obtained from electronic medical records.

2. Definitions and inclusion criteria

Mild head trauma was defined as a blunt head injury (e.g., due to a fall or collision) accompanied by a Glasgow Coma Scale (GCS) score between 13 and 15 at presentation, without evidence of skull fracture or intracranial hemorrhage on imaging, and without loss of consciousness exceeding 30 minutes [18].

Since the medical records lacked information on body weight percentiles at the time of trauma, correlation analysis between BWT and body weight percentile was not conducted.

A psychiatric disorder was defined as any diagnosis made by the Department of Psychiatry at Wonju Severance Christian Hospital within 10 years after the head trauma. All psychiatric diagnoses were established by board-certified child and adolescent psychiatrists according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Diagnoses were determined through clinical interviews conducted during outpatient follow-up visits, incorporating reports from both the child and their caregivers. For ADHD, evaluations focused on symptoms of inattention and/or hyperactivity-impulsivity observed over a 6-month period in multiple settings. PTSD was diagnosed based on the presence of intrusive trauma-related symptoms, avoidance behaviors, and negative alterations in mood or cognition. Adjustment disorder was identified when emotional or behavioral symptoms emerged within 3 months following a stressor and caused significant distress or functional impairment.

The inclusion criteria consisted of patients younger than 18 years with mild head trauma (GCS score of 13–15) and available 10-year follow-up data. Patients with a previous psychiatric diagnosis or major perinatal complications, such as perinatal asphyxia, severe congenital anomalies, or neurological conditions, were excluded.

3. Data collection and variables

1. Patient characteristics

A total of 426 children were identified, and GCS scores were available for 305 of these patients. Among them, 178 children completed a 10-year follow-up, and 18 children (10.6%) received psychiatric diagnoses. Psychiatric disorders included ADHD (three cases), adjustment disorder (three cases), depression (one case), impulse control disorder (one case), PTSD (nine cases), and Tourette syndrome (one case). Demographic characteristics of the patients are presented in Table 1.

Table 1.

Demographic characteristics of the patients

2. Statistical analysis findings

Higher BWT was associated with an increased risk of developing psychiatric disorders. Differences in demographic and birth-related characteristics, including BWT distribution, between patients with and without psychiatric disorders, are summarized in Table 2 and illustrated in Fig. 1. A significant association between higher BWT and psychiatric disorders was identified (odds ratio [OR], 10.08; P=0.017).

Table 2.

Differences between patients with psychiatric disorders and those without after mild head trauma

Fig. 1.

Birth weight of children with and without psychiatric disorders.

Both BWT and LGA status demonstrated significant associations with psychiatric disorders (BWT: OR, 10.080; LGA: OR, 11.662). The results of logistic regression analyses, including ORs and confidence intervals for BWT, LGA status, age, sex, and IUP, are provided in Table 3 and graphically shown in Fig. 2. LGA status was independently associated with psychiatric disorders (OR=11.662, P=0.043). In contrast, IUP, age, and sex did not show significant associations with psychiatric outcomes. Additionally, no significant correlation was found between BWT and body weight at the time of trauma (Pearson’s r=−0.091, P=0.206; Spearman’s rho=0.005, P=0.948).

Table 3.

Impact of birth weight, GA, age, and sex on the development of psychiatric disorders based on logistic regression analysis

Fig. 2.

Impact of birth weight, gestational age (GA), age, and sex on the development of psychiatric disorders. BWT, birth weight; LGA, large for gestational age; AGA, appropriate for gestational age.

1. Key findings

The results indicate a possible association between BWT, specifically LGA status, and psychiatric outcomes following mild head trauma. However, further studies are necessary to clarify the nature of this relationship. Given the limitations inherent in retrospective studies, prospective research should explore this association in more detail, considering additional confounding factors. Specifically, the role of perinatal factors in increasing vulnerability to psychiatric disorders following mild head trauma warrants further investigation. It is also critical to determine whether LGA status alone might contribute to psychiatric vulnerability independent of trauma.

This study specifically targeted children who had mild head trauma to evaluate whether birth-related factors, such as LGA, influence the risk of psychiatric disorders after neurological stress. This method allows examination of potential interactions between perinatal factors and environmental triggers, interactions that may not be evident when each factor is studied independently. By focusing on mild head trauma, we aimed to assess whether birth characteristics like LGA serve as vulnerability factors under conditions of stress rather than as independent risk factors. Although both BWT and body weight percentile at the time of trauma are important indicators, the relationship between these two measures was not explored here and should be addressed in future studies. Additionally, the absence of a significant association between IUP and psychiatric disorders might result from the exclusion of very preterm infants (<29 weeks) and unmeasured environmental factors, such as parental mental health and genetic predisposition.

2. Potential mechanisms

Several biological mechanisms have been proposed to explain the potential link between BWT, LGA status, and psychiatric outcomes following mild head trauma. These include hormonal imbalances, neurodevelopmental changes, neuroinflammation, white matter vulnerability, and gene-environment interactions.

3. Comparison with the existing literature

Previous research has predominantly addressed moderate to severe TBIs in adult populations [30,31]. Most studies have focused on more severe forms of TBI, whereas this investigation specifically examined the association between birth history (BWT, LGA status) and psychiatric outcomes following mild head trauma. Although perinatal factors are recognized to impact neurodevelopmental outcomes, their influence on psychiatric disorders after mild head trauma remains understudied. Consequently, further research in this area is essential.

4. Limitations

This study has several limitations. First, the sample size of the LGA group was relatively small, restricting statistical power and the generalizability of the results. The wide confidence intervals in the logistic regression analysis highlight the necessity for validation in larger and more representative cohorts.

Additionally, the current study did not consider the specific mechanisms of injury, such as trauma type, emotional impact, or the context surrounding the trauma event. Since most psychiatric outcomes involved PTSD, which can be strongly influenced by trauma specifics, the observed association between BWT and psychiatric disorders should be interpreted with caution.

Second, due to the retrospective nature of the study, the reliance on medical records might have led to the underreporting or misclassification of psychiatric disorders. The absence of baseline psychiatric assessments limited the ability to ascertain if certain psychiatric conditions existed before the trauma occurred.

Third, key confounding factors, such as maternal psychiatric history, socioeconomic status, and prenatal environmental exposures, were not accounted for in the analysis. These factors could significantly influence psychiatric outcomes, complicating efforts to isolate an independent relationship between BWT and psychiatric disorders following trauma. Although sensitivity analyses were not possible due to data limitations, future studies should incorporate these variables using stratification or matching techniques.

The wide confidence intervals indicate instability in estimates, suggesting potential overestimation or diminished reliability of the findings. Given the observational study design, further research is needed to clarify these relationships.

Finally, mild head trauma was defined exclusively by GCS scores without consideration of injury mechanisms, loss of consciousness duration, or detailed neuroimaging results—factors that could have affected outcome assessments.

BWT percentile at the time of trauma was unavailable due to the study’s retrospective design. Future studies should include this variable to evaluate its potential role as a mediating factor.

The absence of a significant correlation between BWT and body weight at the time of trauma suggests that BWT might independently impact long-term neuropsychiatric outcomes, irrespective of weight at the time of trauma.

5. Future directions

To address limitations related to causal inference inherent in observational studies, future research should employ prospective cohort or randomized controlled designs to validate these associations.

To improve the reliability of the findings, future research should utilize larger, multicenter prospective cohort studies, thus improving statistical power and the generalizability of findings. Expanding sample sizes, particularly for LGA and SGA groups, will yield more precise risk estimates and reduce variability.

Future studies should also incorporate robust confounding adjustment methods—such as propensity score matching, stratified analyses, and multivariable regression models—to account for essential covariates including parental psychiatric history, socioeconomic status, and delivery methods. To improve diagnostic accuracy and capture subthreshold psychiatric symptoms potentially overlooked in retrospective studies, standardized psychiatric assessments should be employed, and comprehensive long-term follow-up data collected.

To improve risk stratification, future research should incorporate neuroimaging data and trauma-related variables, including injury mechanisms, duration of loss of consciousness, and advanced neuroimaging modalities (e.g., magnetic resonance imaging, diffusion tensor imaging). Longitudinal neuroimaging studies could provide valuable insights into structural and functional changes following mild head trauma, facilitating improved early identification and intervention strategies.

Future investigations into biological mechanisms should include biomarker analyses (e.g., inflammatory markers, stress hormones, neurotrophic factors) and genetic studies. Understanding biological responses to mild head trauma may provide insights into how BWT and neurodevelopment interact, thus enhancing comprehension of long-term psychiatric vulnerability.

Finally, future research should aim to develop predictive models for psychiatric risk stratification, incorporating BWT, gestational age-related growth parameters, neuroimaging results, and other early-life factors. Such predictive models could enable early identification of high-risk children, guiding targeted intervention strategies.

6. Conclusion

This study identified an association between BWT—particularly LGA status—and psychiatric outcomes following mild head trauma. However, the observational design and small sample size of the LGA group require cautious interpretation of results. Wide confidence intervals emphasize the necessity for larger, prospective studies to confirm these findings.

The observed associations may be influenced by unmeasured confounding factors such as maternal psychiatric history and socioeconomic conditions. Therefore, future prospective research should validate these preliminary findings. Incorporating neuroimaging, biomarker analyses, and genetic studies will be essential for clarifying the biological mechanisms underpinning these associations.

Clinically, these findings suggest that perinatal factors, particularly BWT and gestational age, may significantly influence psychiatric risk assessments following mild head trauma. If confirmed in prospective studies, integrating perinatal data into posttraumatic mental health evaluations could improve early detection and intervention strategies.