An recent English study has found that exposure to secondhand smoke makes non-smokers more vulnerable to psychological distress and hospitalization for mental illness. "Cigarette smokers have been shown to have more psychological problems than nonsmokers do, and new evidence suggests that nonsmokers who inhale high levels of secondhand smoke may experience nearly as much psychological distress as smokers, say epidemiologist Mark Hamer of University College London and his colleagues." The study supports the general conclusion that exposure to nicotine may induce negative emotions such as sadness.