Data from two studies, one naturalistic and the other a controlled trial, were analysed to clarify the relationships between independent life events. Expressed Emotion of a key relative, maintenance neuroleptics and the relapse of schizophrenia. It was found that patients in the community who are unprotected by medication are vulnerable either to acute stress in the form of life events or to chronic stress in the form of living with a high Expressed Emotion relative. Patients on regular medication are protected against one or other stress, but are very likely to relapse if the two forms of stress occur together. A model of schizophrenic susceptibility to environmental stress is constructed to incorporate these observations.