Stability of olfactory identification deficits in neuroleptic-naive patients with first-episode psychosis

Objective: Olfactory identification deficits and their relationship to nega tive symptoms in patients with schizophrenia were examined in patients with recent-onset psychosis, the majority of whom were neuroleptic naive. Method: Seventy-four inpatients with a first episode of psychosis (27 with schizophrenia or schizophreniform disorder, nine with schizoaffective disor der, 17 with affective psychoses, and 21 with other psychoses), 49 of whom had not received antipsychotic medication, were compared to 38 age- and gen der-matched normal subjects. Olfactory identification ability was assessed with the University of Pennsylvania Smell Identification Test. Forty patien ts and 13 comparison subjects were reassessed at 6 months to examine whethe r olfactory deficits were specific to schizophrenia or schizophreniform dis order and were stable over time. Results: At baseline, the patients had significant impairment in olfactory identification ability compared to the normal subjects. This difference per sisted after controlling for gender, premorbid or current IQ, smoking histo ry, cannabis use, or the effects of medication. Diagnostic subgroups did no t differ in olfactory identification ability. The deficits remained stable at 6-month follow-up and were associated with negative symptoms at both tim e points. No relationship was found between olfactory identification abilit y and length of either untreated psychosis or illness prodrome. Conclusions: Impairment in olfactory identification ability was apparent fr om the outset of psychotic illness and was not specific to schizophrenia or schizophreniform disorder. No change in the degree of this deficit was fou nd after patients were stabilized and had responded to medication. The defi cit could not be explained by peripheral factors that might contribute to o lfactory identification ability, suggesting that it reflects central mechan isms.