The Scandinavian concept of reactive psychosis, schizophreniform psychosis and schizophrenia.

A diganosis commonly used in the Scandinavian countries, reactive psychosis, is described. Systematic personal follow-up studies from Scandinavia have clearly demonstrated that the clinical and social course is more favourable in this diagnostic group than in schizophrenia, while the course in schizophreniform psychoses in between. The Scandinavian concept of schizophreniform psychosis and of schizophrenia is presented and discussed.