Urbanisation and incidence of psychosis and depression: Follow-up study of 4.4 million women and men in Sweden

Background: Previous studies of differences in mental health between urban and rural populations are inconsistent. Aims: To examine whether a high level of urbanisation is associated with increased incidence rates of psychosis and depression, after adjustment for age, marital status, education and immigrant status. Method: Follow-up study of the total Swedish population aged 25-64 years with respect to first hospital admission for psychosis or depression. Level of urbanisation was defined by population density and divided into quintiles. Results: With increasing levels of urbanisation the incidence rates of psychosis and depression rose. In the full models, those living in the most densely populated areas (quintile 5) had 68-77% more risk of developing psychosis and 12-20% more risk of developing depression than the reference group (quintile I). Conclusions: A high level of urbanisation is associated with increased risk of psychosis and depression for both women and men.