In recent years it has been shown that the course of schizophrenia is influenced by the attitudes and behaviour of the close relatives with whom the schizophrenic person lives. In particular, there is greater risk of relapse if family members show a high degree of criticism, hostility, or emotional over-involvement in relation to the schizophrenic; these attitudes have been described as high expressed emotion (High EE) and are usually assessed by means of the Camberwell family interview. However, as discussed in this paper, there are still many unsettled questions regarding content, validity, causes, effects, and treatment of High EE.