Olfactory threshold selectively predicts positive psychometric schizotypy

Mathur, Naina; Dawes, Christopher; Moran, Paula

Abstract

Olfactory impairment might be useful as a non-invasive pre-morbid biological marker of psychosis. People with schizophrenia show consistent impairments, but an association between olfaction and schizotypy in non-clinical populations is inconclusive and has been somewhat controversial. This is important as impairment in patients may be artefacts of antipsychotic medication. Meta-analyses indicate small effect sizes in non-clinical populations, suggesting prior negative studies may have been underpowered to demonstrate them.
We measured olfaction and psychometrically-defined schizotypy in a sample of 739 non-clinical volunteers [mean age 23.1]. Subsets reported whether they had a history of mental illness in the family or smoked. We used (sniffin’ sticks) to measure threshold detection, discrimination and identification of odours. O-LIFE was used to measure schizotypy.
Lower olfactory-threshold selectively predicted higher scores on the positive dimension, unusual experiences. This association was most evident in sub-groups reporting history of mental illness in the family and/or smoking. There was a weak trend for an association between identification and introvertive anhedonia and discrimination and cognitive disorganization in those with a history of mental illness in the family.
These data support the idea that olfaction merits further investigation as a biomarker for psychosis and that olfactory-threshold detection in particular has potential to selectively predict unusual experiences. Variability in previous studies may have been exacerbated by including different proportions of participants with history of mental illness in the family and/or smoking. We propose that non-clinical participants be stratified by these factors in future
studies of olfaction and potentially any study that measures psychometric schizotypy.

Citation

Mathur, N., Dawes, C., & Moran, P. (2019). Olfactory threshold selectively predicts positive psychometric schizotypy. Schizophrenia Research, 209, 80-87. https://doi.org/10.1016/j.schres.2019.05.014

• Journal Article Type: Article
• Acceptance Date: May 5, 2019
• Online Publication Date: Jun 1, 2019
• Publication Date: 2019-07
• Deposit Date: May 8, 2019
• Publicly Available Date: Jun 2, 2020
• Journal: Schizophrenia Research
• Print ISSN: 0920-9964
• Electronic ISSN: 1573-2509
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 209
• Pages: 80-87
• DOI: https://doi.org/10.1016/j.schres.2019.05.014
• Keywords: Biological Psychiatry; Psychiatry and Mental health
• Public URL: https://nottingham-repository.worktribe.com/output/2022464
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0920996419301756
• Additional Information: This article is maintained by: Elsevier; Article Title: Olfactory threshold selectively predicts positive psychometric schizotypy; Journal Title: Schizophrenia Research; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.schres.2019.05.014; Content Type: article; Copyright: © 2019 The Authors. Published by Elsevier B.V.