SUMMARYThe development of effective preventions for psychosis is hindered by conceptual challenges underlying diagnosis and the fact that few of the many biological risk factors identified to date are sufficiently well understood to form the basis of a targeted intervention. On the other hand, a great deal is known of the psychosocial conditions that increase the lifetime risk of most mental illnesses: surely enough to justify better resourcing of interventions focused on antenatal care and the emotional well-being of children from the early years through adolescence, where as much as a half of all mental ill health has its roots.DECLARATION OF INTERESTNone.