Abstract for presentation at 6th World Congress on Brain Injury

Many recent studies suggest that Mild Head Injury (MHI) in childhood has little, if any, any influence on development. Evidence from the Christchurch Child and Development birth cohort Study, however, suggests that MHI prior to age 10 impacts negatively on psychosocial development, at least when the injury is more severe and perhaps especially after preschool MHI. To establish that early, but not later, MHI influences psychosocial development, the current study compared the effects of preschool MHI with that associated with MHI in school-aged children.
Cases of preschool MHI (0-5y) and later MHI (5-14y) were each divided according to brief inpatient treatment (n=16 and n=18, respectively) and outpatient treatment only (n=40 and n=49, respectively). In addition to covariate analyses, non-MHI groups who received fractures-only, prior to or after 5 years of age (n=19 and n=34, respectively), controlled for non-specific trauma, child and family factors. All injury groups were contrasted with non-injury (reference group) controls (n=466 and n=635, respectively). Psychiatric diagnoses made at age 14-16y and at age 25y were evaluated in these groups of children.
Relative to the reference group, no effects were apparent in any of the fractures or outpatient MHI groups. As reported previously, more severe preschool MHI was associated with more psychiatric diagnoses of ADHD (odds ratio, OR=5.18), Conduct Disorder (OR=4.95) and substance abuse (OR=8.97) at age 14-16 years and ADHD (OR=3.30), substance abuse (OR=3.70) and Mood Disorder (3.68) at 25 years of age. By contrast, more severe cases MHI, between 5 and 14 years, showed no effects on psychiatric outcomes, for either assessment period.
We conclude that, while most instances of childhood MHI at any age have little or no consequences, more severe preschool MHI injury may have lasting effects on mental health and behaviour, suggesting that very young children may be vulnerable the effects of MHI.