This paper describes research which sought to investigate and describe the interpersonal relationships and vulnerability to psychiatric disturbance in severely closed head injured subjects. The head injured subjects were severely injured, with mild or extremely severely injured individuals being excluded from this study. Self-report by the injured individual was compared with relatives' reports. Fifteen head injured people were individually matched with non-head injured people from the general population who acted as controls. Each subject nominated one 'close other' for comparative interview. The dependent variables included interpersonal relationships, non-psychotic psychiatric disturbance and behavioural change. The head injured group differed significantly from the control group in the quantity of interaction but not in the perceived quality of interaction. The groups differed significantly on behavioural change. No significant difference was found between responses given by the head injured and their 'close other' compared with the controls. Deficient quantity of interpersonal relationships and greater vulnerability to psychiatric disorders was shown in this sample. Further research on the assessment of long-term social outcome and psychiatric stability in the head injured could assist in the improved long-term rehabilitation of the survivors.