This study tests whether the same dimensions that have been shown to be relevant to cognitive understanding of physical health problems may also be applied validly to severe mental health problems such as schizophrenia. 22 people with a diagnosis of schizophrenia, and 18 of their relatives, were asked open-ended questions about their understanding of schizophrenia. The responses were recorded and were sorted into common sense dimensions. Construct validity for the use of the dimensions assessed by the most recently updated Illness Perception Questionnaire (IPQ-R) was examined. The results suggest that the dimensions of the IPQ-R are present in people's understanding of schizophrenia. Copyright © 2005 John Wiley & Sons, Ltd.