Alexithymia modulates the attitudes towards odors but not the olfactory abilities or the affective reactions to odors

PLoS One. 2023 Jun 6;18(6):e0278496. doi: 10.1371/journal.pone.0278496. eCollection 2023.

Abstract

Although emotion and olfaction are closely linked, only a few studies have investigated olfactory processing in alexithymia, a condition characterized by altered emotional processing. These results do not allow comprehensive conclusions on whether individuals with alexithymia present lower olfactory abilities or only altered affective reactions and awareness of odors. Three pre-registered experiments were conducted to clarify this relation. We assessed olfactory functions, the affective qualities of odors, the awareness of odors, the attitudes towards them, and the ability to form olfactory images in the mind. Bayesian statistics were used to assess differences between low, medium and high alexithymia groups, and Linear Mixed Models (LMMs) were applied to investigate the modulation of the affective and cognitive components of alexithymia. We observed that individuals with a high level of alexithymia presented the same olfactory abilities, and did not show differences in their rating of odors compared to individuals with low alexithymia levels, while they reported lower levels of social and common odor awareness and a more indifferent attitude towards odors. Olfactory imagery was not affected by alexithymia level, and the affective and cognitive components of alexithymia, when considered separately, modulated olfactory perception differently. Learning more about olfactory perception in individuals with alexithymia leads to a better understanding of how alexithymia impacts the perception of hedonic stimuli coming from different sensory modalities. Our results imply that treatment goals for alexithymia should be the enhancement of the conscious perception of odors, supporting the use of mindfulness-based protocols in the alexithymia treatment.

MeSH terms

  • Affective Symptoms / psychology
  • Attitude
  • Bayes Theorem
  • Humans
  • Odorants
  • Olfactory Perception*
  • Smell*

Grants and funding

The present study is funded by the European Commission Horizon 2020 research and innovation program under grant agreement No. 824153, https://ec.europa.eu/programmes/horizon2020/en received by CG. EDB Ph.D. scholarship is funded by the above mentioned grant. CC is supported by a grant of the Department of General Psychology from MIUR (Dipartimenti di Eccellenza DM 11/05/2017 n. 262, https://www.miur.gov.it/dipartimenti-di-eccellenza). FF is supported by the FWF, Austrian Science Fund, through grant KLI 639 and I 418, https://www.fwf.ac.at/en/. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.