Among 9,288 Ontario students, those with a history of traumatic brain injury were more likely to use cannabis and engage in other risky behaviors, with sex and age moderating specific associations.
Read this if you have had a head injury and want to understand the relationship between brain injuries and substance use in teenagers.
About 1 in 5 students reported lifetime traumatic brain injury
What the researchers found
In a population-based survey of 9,288 Ontario students in grades 7-12, lifetime traumatic brain injury (TBI) was reported by 23.1% of males and 17.1% of females. TBI was associated with cannabis use, cannabis dependence, drug use problems, cigarette smoking, psychological distress, suicidal ideation, bullying, and poor academic performance.
Sex moderated the relationship between TBI and cigarette smoking. Sex and age together moderated TBI's relationship with daily smoking, alcohol use, and physical injuries. Late adolescent males with TBI showed elevated daily smoking and injuries, while their female counterparts showed elevated past-year drinking.
Why it matters
TBI is common in adolescents and is a known risk factor for substance use. Understanding that the TBI-substance use relationship differs by sex and age helps target prevention and intervention efforts more precisely.
The numbers in context
9,288 students. TBI prevalence: 23.1% males, 17.1% females. Cannabis use, cannabis dependence, and drug use problems were all associated with TBI history. Sex moderated TBI-smoking; sex and age moderated TBI-alcohol and TBI-injury relationships.
How the study worked
Population-based cross-sectional survey of 9,288 Ontario 7th-12th graders (62% response rate). TBI was defined as a head blow resulting in at least 5 minutes of unconsciousness or overnight hospitalization. Thirteen behavioral and psychological correlates were examined with moderation analyses for sex and age.
What this study cannot tell us
Cross-sectional design cannot determine whether TBI preceded or followed substance use. Self-reported TBI may be subject to recall bias. The 62% response rate raises questions about non-response bias, though preliminary analyses found no evidence of bias in TBI reporting.
How to read the evidence
Large population-based school survey with appropriate moderation analyses, though cross-sectional design limits causal inference.
When this study was published
Published in 2014.
The bigger picture
The high prevalence of TBI in this school-based sample (approximately 1 in 5 students) underscores that brain injury is not rare in adolescence. The association with substance use and mental health problems suggests TBI should be routinely screened for in youth presenting with these issues.
Questions still open
- Does TBI causally increase cannabis use risk, or do risk-taking youth sustain more TBIs? Would TBI-informed substance use prevention programs be more effective? Do the sex differences reflect biological vulnerability differences or behavioral exposure differences?
Common questions
Are teens with brain injuries more likely to use cannabis?
How common are brain injuries in teenagers?
Read the original research
The moderating effects of sex and age on the association between traumatic brain injury and harmful psychological correlates among adolescents.
PloS one, 9(9), e108167
Citation
Ilie, Gabriela; Adlaf, Edward M; Mann, Robert E; Boak, Angela; Hamilton, Hayley; Asbridge, Mark; Colantonio, Angela; Turner, Nigel E; Rehm, Jürgen; Cusimano, Michael D. (2014). The moderating effects of sex and age on the association between traumatic brain injury and harmful psychological correlates among adolescents.. PloS one, 9(9), e108167. https://doi.org/10.1371/journal.pone.0108167
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