Professionals have suggested that aggressiveness, substance abuse, and criminality contribute to poor outcomes after brain injury. There is considerable research regarding post-injury aggressive behaviour, but limited information concerning criminal behaviour and alcohol use patterns. With a sample of 327 patients varying in severity of traumatic brain injury, the present investigation examined alcohol use patterns, arrest histories, behavioural characteristics, and psychiatric treatment histories. Relative to the uninjured population, analysis revealed relatively high incidence of heavy drinking, both pre- and post-injury, among patients with a history of arrest. Increases in abstinence rates were found regardless of arrest history. In addition, a history of arrest was associated with a greater likelihood of psychiatric treatment. Findings also indicated relatively high levels of aggressive behaviours. Discussion focuses on implications for evaluation, rehabilitation, and future research. © 1995 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.