Background Evidence has been accumulating that it may be possible to achieve prevention in psychotic disorders. The aim of the Prevention Of Psychosis (POP) study is to reduce the annual incidence of psychotic disorders in a catchment area population through detection and intervention in the prodromal phase of disorder. Prodromal patients will be recruited through information campaigns modelled on the Scandinavian early Treatment and Intervention in Psychosis (TIPS) study and assessed by low-threshold detection teams.