Eric Olof "Olle" Hagnell (July 29, 1924 - April 1, 2011) was a Swedish psychiatrist and epidemiologist.
In 1966, he received a doctoral degree in psychiatry from Lund University.
After completing his doctoral program, Hagnell became a docent and worked as a visiting professor at Columbia University in New York.
[2] During his career at Lund University, Hagnell was recognized as a leader in research into psychiatric epidemiology, the study of the root causes of mental disorders in a population-wide sense.
During his research career, he worked as a research director for the Lundby Study, a longitudinal survey of the mental health in a total Swedish population between 1947 and 1997. International reviewers have stated that "the Lundby Study has produced prevalence, incidence and outcome data on depression and anxiety over many years, and is one of the few studies capable of producing reliable data on changes in incidence".