The Underlying Mechanisms in the Association Between Traumatic Brain Injury in Childhood and Conduct Disorder Symptoms in Late Adolescence

Abstract

The present study examined i) the direct association between traumatic brain injury (TBI) in childhood and conduct disorder symptoms in adolescence, ii) whether this effect is mediated by impulsivity and/or callous unemotional traits (CU traits), and iii) whether these indirect effects are moderated by childhood family adversity and adolescent substance use. Utilising data from the Avon Longitudinal Study of Parents and Children (ALSPAC), participants with head injury information up to 12 years (4.5 years, 5.4 years, 6.5 years, 8.6 years, 11.7 years) were identified and categorised into a TBI (n = 409), orthopaedic injury (n = 1469) or non-injury group (n = 5685). Psychosocial factors such as impulsivity at 13 years, CU traits at 13 years, childhood family adversity (between birth to 4 years) and substance use at 14 years were collated for moderated mediation analyses. Conduct disorder symptoms were assessed at 16 years of age. TBI and conduct disorder symptoms were positively associated, and this association was mediated by impulsivity but not CU traits. The indirect effects were higher in magnitude for individuals with higher levels of childhood family adversity. Adolescent substance use was not found to moderate the indirect effects between TBI and conduct disorder symptoms. These results were specific to TBI individuals, and not in participants with orthopaedic injury and no reported injuries. Targeting impulsivity and early family adversity may alleviate the risk of conduct disorder symptoms following TBI in childhood. These findings have important implications for informing neuro-rehabilitative and preventative measures in clinical and community settings.

Keywords: ALSPAC; Callous unemotional traits; Conduct disorder symptoms; Family adversity; Impulsivity; Substance use; Traumatic brain injury.

Fig. 1

Selected sample of the study. 7118 participants were excluded as they did not have injury information from birth up to 12 years of age. TBI Traumatic brain injury

Fig. 2

Moderated mediation models (A) Model 2: Mediation model, testing the hypothesis wherein the presence of impulsivity and callous unemotional traits would mediate the relationship between TBI and conduct disorder symptoms. B Model 3: Family adversity moderation model, testing hypothesis wherein the presence of family adversity would moderate the strength of indirect effects between TBI and conduct disorder symptoms. C Model 4: Substance use moderation model, testing hypothesis wherein the presence of substance use would moderate the indirect effects between TBI and conduct disorder symptoms. CU traits = Callous unemotional traits

Fig. 3

Model 2: Mediation model, testing hypothesis A wherein the presence of impulsivity and callous unemotional traits would mediate the relationship between TBI and conduct disorder symptoms. Unstandardised indirect effects are presented. The effects on the direct path from traumatic brain injury to conduct disorder symptoms depict the direct effect and the (total effect). Confounders in this model include sex, intelligence, family adversity, early conduct disorder symptoms (at age 8), early impulsivity (age 8) and harsh parenting. *p value < 0.05, **p value < 0.00

Fig. 4

Moderation effects of family adversity on the relationship between TBI and conduct disorder symptoms

Fig. 5

Model 3: Family adversity moderation model, testing hypothesis B whereby the presence of family adversity would moderate the strength of indirect effects between TBI and conduct disorder. Unstandardised indirect effects are presented. The effects on the direct path from traumatic brain injury to conduct disorder depict the direct effect and the (total effect). Confounders in this model include sex, intelligence and early conduct disorder symptoms (at age 8), early impulsivity (age 8) and harsh parenting. *p value < 0.05, **p value < 0.00

Fig. 6

Model 4: Substance use moderation model, testing hypothesis B wherein the presence of substance use would moderate the relationship between TBI and conduct disorder symptoms. Unstandardised indirect effects are presented. The effects on the direct path from traumatic brain injury to conduct disorder symptoms depict the direct effect and the (total effect). Confounders in this model include sex, intelligence, family adversity and early conduct disorder symptoms (at age 8), early impulsivity (age 8) and harsh parenting. *p value < 0.05, **p value < 0.00