"It is the only sense that passes straight to this area of the brain, and so any vulnerability involving these neural circuits can affect our labeling of smell," says Brewer.
"This area of the brain deals with the primary emotions. It is the part that processes such things as threat and emotion before transferring this information into the frontal (language) area of the brain," he says.
"It is either the transfer of emotional information to the frontal lobe, or functioning in the frontal lobe itself that appears to be compromised in those suffering from psychosis."
As for the nature versus nurture controversy, there are, as with many debates, two extreme camps: one camp says that psychosis is entirely a biological, or genetic, phenomenon. The other camp says it is entirely a result of social influences.
"Our research suggests that psychosis may involve an active synergy between the two," says Brewer.
"A person could be born with a biological vulnerability to various forms of psychosis, that may manifest itself if put under particular psychosocial stresses," he says.
The ultra high-risk for psychosis subjects chosen for the study came from the Personal Assessment Crisis Evaluation (PACE) clinic - ORYGEN Youth Health, a University of Melbourne-Department of Psychiatry & Psychology clinic that is the first of its kind in the world. It provides assessment monitoring and support for young people who have met criteria for being at imminent risk of developing a psychotic illness and who have experienced mental status changes. This clinic is managed by Assoc Prof Alison Yung and Lisa Phillips under the direction of Professor Patrick McGorry.