Predicting Schizophrenia with Smell

Schizophrenics have difficulty identifying odors, and problems with
the sense of smell seem to be linked with the disease. Among high-risk
patients, a recent study found, problems with olfaction predicted who was
most likely to develop the disorder. The findings suggest that testing a
patient’s sense of smell could become a useful method to predict
who is most likely to develop the psychiatric disorder.

Warrick Brewer, a psychiatrist from the University of Melbourne in
Australia, and colleagues compared the olfactory abilities of a group of
81 high-risk patients against those of 31 volunteers in a control group.
The at-risk group were recruited from a university sponsored clinic that
monitors teens who appear to be developing a serious mental illness, yet
have not yet had any psychotic episodes. After 18 months, 22 of the
high-risk patients suffered psychotic episodes and 12 were found to be
schizophrenic.

Of the participants involved in the study, only those who later
became schizophrenic scored significantly worse in initial olfactory
testing. The findings, published in this month's
American Journal of Psychiatry, may help develop a
diagnostic tool to predict who is most at risk for the disorder. Brain
imaging, clinical symptoms and genetics have failed to find a reliable
predictor.

An olfactory connection with schizophrenia has been previously
identified. Brewer notes that the two are intimately related, as both
involve the same area of the brain. Prior to this study, it was not known
if the loss of smell predicted the onset of the disorder or came as a
result of it. The study strengthens arguments that a biological component
is vital in the disorder's development.