Abstract
The paper describes the epidemiology of mental disorders in Norway with emphasis on studies based on admission statistics and community surveys. An important tool in the first type of study has been the National Register of Psychotics, going back to 1916. This register is now, unfortunately, closed down, which makes is much more difficult to conduct such studies in the future. Among social variables studied in relation to first admissions for psychoses are migration, education, occupation and type of neighbourhood. During later decades a number of community surveys have been conducted, where psycho-social variables, like social support, social participation and negative life events, are included among the independent variables, in addition to structural social variables. Recently, questionnaires have been developed to map mental health, risk factors and protective factors in the community, for the purpose of prevention. In studies of mental disorders in various Norwegian communities the prevalence is found to be in the range of 15–20%.