In contrast with the prevention of common physical diseases leading to disability, the primary and secondary prevention of schizophrenia, also a disorder entailing many years of life in disability, are still being neglected. A precondition of preventive intervention in schizophrenia is the detection of aetiological risk factors that can be eliminated or modified. As possible targets pre-, peri- and postnatal complications, urbanicity and early behavioural risk indicators are discussed. As examples of early prevention targeted at risk indicators successful attempts to prevent depression and violence are considered. The most promising approach at present is secondary prevention focused on early illness course. Based on a controlled retrospective assessment of 232 first illness episodes the course of prodromes, impairments and psychotic symptoms prior to the climax of the first episode is shown. Most of the social consequences occur in the early course before the first treatment contact. Tools sufficiently validated are not yet available for early diagnosis and prediction of psychosis onset at the prepsychotic stage. The criteria for inclusion in intervention must be supplemented by traditional high-risk criteria such as family history of schizophrenia and pre- and perinatal complications. However, this procedure excludes large proportions of at-risk persons. Appropriate early intervention at the prepsychotic and the early psychotic stages, as well as relevant ethical considerations are discussed. The frequency of and distress associated with single psychotic symptoms in the general population are potent predictors of a psychosis. The vision of treating this early illness dimension with third-generation, side-effect-free antipsychotics or of preventing its onset by oestrogen-like substances is discussed.