Olfactory identification deficiency and WCST performance in men with schizophrenia

Several studies using the University of Pennsylvania Smell Identification T est (UPSIT), which requires forced choice olfactory identifications, have r eported olfactory, identification deficits in patients with schizophrenia. This report examines the possible links between olfactory identification (u sually attributed to the orbitofrontal cortex), and executive functions (us ually attributed to dorsolateral prefrontal cortex) in 24 male patients wit h schizophrenia and 21 male comparison subjects. Olfactory performance was investigated under two conditions: spontaneous identification and forced ch oice identification. Executive function was assessed with the Wisconsin Car d Sorting Test (WCST). Compared with controls, patients with schizophrenia exhibited a higher average number of cigarettes smoked per day, lower spont aneous identification scores on olfactory performance, and a higher percent age of perseverative errors on the WCST; there was a significant relationsh ip between the two performance measures. Simpson-Angus scores, neuroleptic drug treatment levels, and scores on the Positive and Negative Syndrome Sca le were not correlated with either olfactory measure. The lack of correlati on between the forced choice olfactory identification score and the WCST sc ore is consistent with findings in previous studies that used the UPSIT. By contrast, use of a spontaneous identification condition to assess olfactor y performance did produce a significant association with WCST performance. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.