A study of 720 youths between the ages of 11 and 20 who were in rehabilitation facilities in Missouri has found that nearly one in five of them had suffered from a traumatic brain injury, defined as a head injury causing unconsciousness for more than 20 minutes. Fights and other assaults were a significant source of the injuries which were more common in boys than girls. The participants with the brain injury were significantly more likely to have used heroin, cocaine, crack, marijuana and ecstasy. They also had a significantly earlier onset of criminal and substance-using behaviours and more lifetime substance-abuse problems and suicidal tendencies than the other youths.
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