Substance use, criminal behaviour and psychiatric symptoms following childhood traumatic brain injury: findings from the ALSPAC cohort.

Recent research suggests a link between traumatic brain injury (TBI) in youth and later risk behaviour. We explored the association between mild TBI and psychiatric symptoms, substance use and criminal behaviour using data from a longitudinal birth cohort. Participants with mild TBI (n = 800), orthopaedic injuries (n = 2305) and no injuries (n = 8307) were identified from self and parent reports up to age 16 years. Self-report measures of substance use (alcohol, tobacco and cannabis) and criminal behaviours, and parent-reported psychiatric symptoms were collected at age 17 years. Analyses were adjusted for pre-birth and early childhood confounders. Participants with a TBI showed increased odds of hazardous alcohol use compared to those with no injury and those with an orthopaedic injury. Relative to those with no injury, participants with a TBI showed increased odds of problematic use of tobacco and cannabis, being in trouble with the police and having more parent-reported conduct problems. Sustaining either a TBI or an orthopaedic injury increased the odds of offending behaviour compared to having no injuries. There was no clear evidence of association between orthopaedic injury and the other risk outcomes. The increased odds of risk behaviour associated with TBI relative to no injury replicated previous research. However, the inclusion of a non-brain-related injury group adds evidence for a possible causal pathway between mild TBI in youth and later hazardous alcohol use only. This highlights the importance of including an additional negative control injury group in mild TBI research.