Expressed emotion (EE) has substantial scientific support as a predictor of relapse of positive symptoms. The median relapse rate in a high-EE environment is 48%, compared with 21% in a low-EE environment. This effect does not seem to be due to confounding with other variables, but it is subject to limitations in its scope of application. EE probably determines relapse through its effect on emotions and symptom control. A stress-vulnerability model of relapse is advanced that incorporates biological factors as well as cycles of mutual influence between symptomatic behaviour, life events, and EE. Aversive types of behaviour in patients and their relatives are seen as understandable reactions to stress that are moderated by social perceptions and coping skills. Families have made positive achievements, including the provision of non-invasive support.