The aim of the current study was to examine the function alcohol and substances serve for the ABI/TBI individual, to explore the ABI/TBI individuals' experiences with alcohol and substance use before and after their injury. Further aims were to examine the views and attitudes of these individuals towards the use and abuse of alcohol and substances, and to investigate whether injury had affected their alcohol and substance use habits or attitudes. Semi-structured qualitative interviews were conducted with 7 male participants. Grounded Theory was used to analyze interviews and developed a model consisting of 3 major themes: negative attitudes, stress/anxiety and re-definition of the self, sub-themes included fear of re-injury, wake-up calls and shame around previous use. It was found that the theme of 'Stress/Anxiety' was relevant in understanding the function of alcohol, substance and cigarette use for this ABI/TBI sample both before and after injury. It was apparent that the majority of participants had extremely negative attitudes towards the use of alcohol, in particular substance use and abuse. 'Fear of re-injury' seemed to be the driver of these negative attitudes, as well as being responsible for changes that occurred in participant's use habits following injury. 'Shame around previous use' was another theme that contributed to the individual's desire to have a new conception of self. It was observed that the theme of 'Re-defining the self, as well as 'wake-up calls' were important in understanding the changes that occurred in alcohol, substance and cigarette use habits following ABI/ITBI. Methodological strengths and limitations of the current study are examined. Practical implications and suggestions for future research are also explored.