I was surfing around the net one day and I found this article about scientists who are creating a machine that will detect acetone in someone's breath. Acetone can be a sign that someone suffers from diabetes, so in theory this machine could use scent to diagnose this disease.
That story brought to mind other stories I've heard about people using dogs to sniff out cancer in people. According to this article:
"The results of the study showed that dogs can detect breast and lung cancer with sensitivity and specificity between 88% and 97%. The high accuracy persisted even after results were adjusted to take into account whether the lung cancer patients were currently smokers. Moreover, the study also confirmed that the trained dogs could even detect the early stages of lung cancer, as well as early breast cancer."
People have even tried "smelling" schizophrenia.
But what if there were a pheromone for violence? About a year ago, someone approached my hospital and wanted to bring in dogs to do a study on violence. They wanted to see if canine scent detection could be used to predict which patient would be aggressive. The idea seemed pretty bizarre to me at the time, and in fact there is nothing in PubMed to suggest that it would work.
While googling around on the topic of scent detection I also found this novel, The Nadjik Pheromone. The plot is based on the idea that somebody discovers a pheromone that gets emitted when someone lies. It's an interesting idea. The author came up with the idea when he heard about people using fMRI for lie detection.
I don't really have a conclusion for this post, I just thought I'd throw out some ideas. Maybe someday people will be giving "truth perfume" for Christmas.