Turetsky BI, et al. - The researchers sought to investigate the structural anomalies of the peripheral olfactory system in psychosis high-risk subjects. In this study, psychosis-risk youths showed an array of sexually dimorphic and laterally asymmetric anomalies of the peripheral olfactory system and these were consistent with a developmental disruption primarily affecting male fetuses. The identification of at-risk subjects with poor prognosis was enhanced with these structural biomarkers before their clinical trajectory was apparent.

• The researchers compared 39 clinical high-risk (CR) subjects (24 M/15F) to 36 low-risk (LR) subjects (19 M/17F).
• In this study, olfactory measures derived from 3 T MRI scans included olfactory bulb volume, primary olfactory cortical gray matter volume, and the depth of the olfactory sulcus overlying the bulb.
• Nasal cavity volumes were also evaluated with acoustic rhinometry.

• Bilateral reductions in olfactory bulb volume and abnormal asymmetries of the posterior nasal cavities and olfactory sulci (left reduced relative to right) were observed in male CR subjects.
• Furthermore, post-hoc contrasts demonstrated reduced left, but not right, olfactory cortical gray matter volume.
• Although female CRs exhibited similar trend effects, they had no significant abnormalities.
• Across all CR subjects, left olfactory bulb volume correlated with negative, but not positive, symptoms.
• In a classification analysis, olfactory measurements distinguished male CR from male LR subjects with 93% sensitivity, with 80% target specificity.
• The comparable sensitivity was 69% among females.