Data from the Camberwell Collaborative Psychosis Study were used to examine the proposition that there is an excess of life events preceding the onset of psychoses of all types. Of 97 patients from the study who had episodes within the past year that were datable, 51 had developed psychotic symptoms from an essentially symptom-free state, 29 had been suffering only from neurotic symptoms, and 17 had experienced a marked exacerbation of psychotic symptoms. DSM-III diagnoses were collapsed into three major groups: 51 cases of schizophrenia; 31 cases of mania; and 14 cases of depressive psychosis. Life-event histories were taken for the six months before onset, and when these were compared with equivalent histories from a psychiatrically healthy sample from the local general population, there was a significant excess of life events, particularly in the three months before onset of psychosis. This was apparent in all groups, and remained even when events were restricted to the independent category. The excess of events began rather earlier than has been found in previous studies. In our view, this study provides some of the strongest evidence for a link between life events and the emergence of psychotic symptoms.