Abstract
This is the case of a young farm worker presenting with episodes of acute organic psychosis superimposed on a state of chronic anergy and hypersomnia. It is suggested that he developed an encephalopathic illness presenting with an organic bipolar affective disorder as a result of organophosphate exposure. In proposing this aetiology, an hypothesis is developed which links clinical observations and investigative results with research findings in relation to organophosphorus compounds and neuropharmacology.