Polysubstance abuse and traumatic brain injury: Quantitative magnetic resonance imaging and neuropsychological outcome in older adolescents and youngadults

Few studies have examined the consequences of alcohol and drug abuse on TBI though they commonly co-occur. Both TBI and substance abuse independently result in neuropathological changes in the brain such as ventricular enlarg ement and cortical atrophy, thus it is reasonable to hypothesize that the c ombination of the two would result in more significant cerebral damage. In this study, 3 groups of patients-traumatically brain injured (TBI) with sub stance abuse (N = 19), TBI without substance abuse (N = 19), and substance abuse with no TBI (N = 16)-were compared with normal controls (N = 20) on s everal quantitative MRI (QMRI) measures. Since TBI most frequently occurs i n older adolescents and young men, we examined only male participants betwe en 16 and 30 years of age. Comparing young substance abusers to controls re sulted in no QMRI differences. When controlling for head injury severity, t he effects of substance abuse in combination with TBI resulted in greater a trophic changes than seen in any other group, TBI and substance abuse patie nts' neuropsychological test performances also were examined, and no differ ences were found among patient groups on any measures. These findings have implications for the deleterious interaction of substance abuse combining w ith TBI to result in greater neuropathological changes that can be detected by QMRI techniques.