Follow your nose
The sense of smell is often impaired in people with mental or neurodegenerative diseases. Where does that come from? And can this connection be used?
It's not often that a scientific experiment brings tears to the subjects' eyes. However, exactly this reaction was expected in the experiments that took place in 2014 at the Technical University of Dresden: The scientists wanted to investigate how depression affects the ability to smell. They showed their participants - 24 women and 7 men - the final scene from the film "The Champ". In it, a little boy cries for his dying father, who was badly injured in a boxing match. The heartbreaking cleavage very reliably constricts viewers' throats. The film owes its meteoric rise in research to this fact: since the 1990s, psychologists and physicians have used it regularly to study sad states of mind – as did the olfactory researchers Elena Flohr, Elena Erwin, Ilona Croy and Thomas Hummel in 2014. After the screening, they let their bruised subjects sniff the stench of rotten eggs. The participants processed the stimulus more slowly than usual, as measured by electroencephalography (EEG) showed. In addition, the peak in the brainwave curve, which was observed shortly after the onset of the stench, was slightly smaller in the sad state.
The differences weren't that big. However, they fit the picture: as early as 2003, the Düsseldorf psychologist Bettina Pause was able to identify similar changes in the EEG of depressive patients. After successful drug treatment, these abnormalities disappeared again. Pause was also one of the first to show that people with depression only perceive smells at a higher intensity than he althy people and that their ability to smell increases again after therapy …