Unilateral olfactory perception and magical ideation

We assessed olfactory detection thresholds and discrimination abilities in 40 healthy right-handers (20 women and 20 men). All subjects were also requ ired to complete the Magical Ideation (MI) scale, a well-validated 30-item schizotypy inventory. Over both nostrils, we found elevated thresholds for subjects with high MI scores (at or above the median score of 9.0) compared with those with low scores. In men but not women, specifically left-nostri l acuity was inversely correlated to MI raw scores. MI was unrelated to olf actory discrimination performance. These results suggest an association, at least in healthy men, between even moderate signs of schizotypy and defici ts in odor detection. The selective impairment of left-nostril performance adds to the growing evidence for left temporal lobe functional abnormalitie s in people high on MI. This laterality effect is known from previous studi es in patients with schizophrenia. However, as a rule, in psychiatric patie nts olfactory identification rather than simple detection performance was f ound to be impaired, indicating that the integration of odor information is affected at different levels of processing in schizotypy compared with sch izophrenia. Work with completely normal subjects may reasonably complement clinical studies of olfactory perception. Among its advantages are the good subject compliance and the absence of medication effects. (C) 2001 Elsevie r Science B.V. All rights reserved.