This national survey from Korea asked questions about many aspects of health and one of these was about sense of smell. The prevalence of olfactory problems was 5% in the adult group surveyed, and other studies would suggest that this self-reported figure was an underestimate. What was more interesting was the apparent higher prevalence of suicidal ideation and depression in the group with self-reported smell problems compared to the self-reported ‘normosmic’ group. This is clearly a complex epidemiological problem and may not be as it seems at face value due to confounding factors and the nature of the study. Other factors that were related to olfactory problems included: social class (‘job, education’), alcohol intake (‘drinking habit’), waist circumference and rhinitis. Whether mental health affects reporting of smell problems is also a possible factor here.