The purpose of this study is to examine the rhetorical function of mental illness regarding the way it constructs the public view of individuals with mental illness. The study is based on the following research questions: What is the rhetorical function of mental illness during the time period 1951-2016? How has the language used to describe mental illness changed over time? How does language use construct and deconstruct the public view on mental illness? Methods based on theories about ideology, genre and discourse have been used to disclose the view on mental illness in medical discourse. The results indicate that the rhetorical function of mental illness is to construct what is normal or deviant. The results also suggest that language use changes the public perception of mental illness. This study shows that the medical discourse is a powerful tool to decrease stigma related to mental illness.