Medicine: psychiatric scratch-and-sniff

It originated in a discovery by Melbourne University researchers of a link between these illnesses and a poor ability to identify smells.

To test their theory, they developed a set of 40 scratch-and-sniff cards and asked people to identify the smell from a list of four possibilities, such as coffee, roses, oranges and petrol.

Professor Warwick Brewer, from the university's Orygen Research Centre, said the people who later went on to develop a brain disorder had demonstrated difficulty correctly answering more than half the questions.

He said the simple test also could be used by relatives of people with these conditions.

"Because of the genetic link in many illnesses, it is hoped the test could also be used by family members of people who have developed an illness of the brain."

Professor Christos Pantelis, from the Melbourne Neuropsychiatry Centre, said smell ability provided unique information about brain structure and function.

"Mental illness can arrest the full maturation of the frontal lobe, while degenerative illness can damage it," Professor Pantelis said.

Chance of clinical utility ever: 0.2%. But cool enough.

As an added bonus, Elissa Ely had a touching case anecdote in yesterday's NYT: A Heart That Needed Fixing, a Mind That Said No. And yes, I just said touching. I'm that lame.