OBJECTIVE: The authors examined the relationship between deficits in
olfactory identification and duration of illness in young and elderly
patients with schizophrenia. METHOD: Olfactory identification performance
of 38 patients with schizophrenia and 40 normal subjects was compared by
using the University of Pennsylvania Smell Identification Test. RESULTS:
The schizophrenic patients demonstrated olfactory deficits relative to the
comparison group, and the elderly schizophrenic patients displayed a
greater magnitude of olfactory deficit than the younger patients.
Independent of normal aging effects and cognitive deficit, patients with
schizophrenia showed a strong relationship between olfactory identification
scores and duration of illness, which suggests that olfactory abilities
decline progressively over the course of the disorder. CONCLUSIONS: In
contrast to other neuropsychological measures that have been reported to be
stable over the course of illness, olfactory identification abilities
deteriorate steadily in patients with schizophrenia, even for those with
relatively recent onset.