BACKGROUND Neurobehavioural disability often leads to serious social handicap. Many individuals never recover full social independence and will remain largely dependent upon family support, imposing a significant and potentially life-long psychological burden on those who care for injured relatives. Close relationships are at risk and many partnerships break down, increasing the risk of social isolation and subsequent psychological distress to the survivor. OBJECTIVE The aim of this paper is to examine the nature of some cardinal features of neurobehavioural disability that contribute to poor psychosocial outcome; consider their organic origins, and problems associated with standardised methods of assessment. METHODS A review of clinical literature addressing neurobehavioural disability after TBI. RESULTS Many forms of neurobehavioural disability are subtle but have a pervasive impact on psychosocial outcome in general and relationships in particular. CONCLUSIONS Caution is recommended when employing standardised tests to identify the complex and often subtle nature of neurobehavioural disorders. More work is needed to define the nature and impact of different forms of neurobehavioural disorders that comprise this complex form of disability.