A significant share of the excess mortality among people suffering from mental illness is due to unhealthy lifestyles. Obesity, smoking, unhealthy diets and sedentary behaviour is twice as frequent among people with mental illness, but the willingness to improve lifestyle is as high as in healthy people. Based on a review of the literature we conclude that it is possible for people with mental illness to change their lifestyle, but they encounter a number of barriers to lifestyle changes, including their symptoms, adverse drug effects and their life situations.