Current models of post-concussional symptoms after mild head injury rest on the dichotomy between organic and psychogenic factors, which underpins Lishman's formulation; organic genesis and psychologically-driven persistence (Br J Psychiatry 1988; 153: 460-469). Recent prospective neuropsychological and bio-social studies of mild head injury, and perspectives from cognitive behavioural and health psychology, are reviewed. It is argued that the organic-psychogenic conceptualization inadequately explains chronic post-concussional symptoms. Psychosocial and cognitive-behavioural factors and the coping process may influence post-concussional symptoms over their entire time course, in particular the late phase. A multifactorial model of chronic post-concussional symptoms is proposed which integrates biological processes with these factors. It is through the recognition and identification of separate processes that questions about outcome, the limits of the impact of organic and psychosocial factors, the nature of exaggeration, and appropriate therapy, may be resolved.