Lifetime history of traumatic brain injury among persons with substance use disorders

Objective: Determine (a) if there are sub-groups of individuals with substance use disorders distinguished by their pattern of sustaining traumatic brain injury (TBI) over the lifetime and (b) whether sub-group membership affects current functioning. Design: Secondary analysis. Settings: Outpatient substance abuse treatment programme and state prison. Participants: Two hundred and fifty-seven participants with lifetime histories of both TBI and substance used disorder drawn from two previous studies of (a) persons in substance abuse treatment and (b) prison inmates. Main outcome measures: Ohio State University TBI Identification Method, speed of information processing, working memory, disinhibition, cognitive complaints, sociopathy and substance use disorder severity. Results: Seven clusters of lifetime history of TBI were characterized by the severity of injuries, age at occurrence and presence of a period of time when multiple mild injuries were incurred, often receiving no medical attention. Cluster membership contributed to the prediction of cognitive performance (i.e. processing speed), self-reported cognitive problems and alcohol and other drug severity. Conclusions: In addition to injury severity, age at injury and periods of repeated injury may be distinguishing aspects of a lifetime history of TBI for persons with substance use disorders. Results suggest that clinicians would benefit from knowledge of a person's full history of TBI.