Sydney Giron ’26

The olfactory system is involved in ingestive behavior, awareness of environmental hazards, and social interactions. Olfactory function has been used as both a diagnostic and prognostic marker for psychiatric and neurodegenerative disorders. Previous studies suggest an association between olfactory impairments and negative symptoms that are associated with psychotic disorders. These symptoms include avolition, which is a lack of motivation and alogia, which is a lack of expression capability. Schizophrenia spectrum disorder is characterized by such symptoms and individuals often also experience olfactory dysfunction. Psychotic disorders, excluding schizophrenia spectrum disorder, also demonstrate olfactory dysfunction and negative symptoms thought to a statistically less significant degree. There is an interesting link between olfactory function and variance in neural activity and behavior that is unique amongst all sensory modalities: pleasant and unpleasant odors have a strong effect in affecting behavior. For example, unpleasant odors are associated with increased heart rate and faster response times compared to pleasant odors. Though links have been established, few studies have assessed differential associations between negative symptoms and odor identification. However, clinical psychologist Aprajita Mohanty and her colleagues at Stony Brook Medicine examined whether pleasant and unpleasant odor identification demonstrate differential relationships to avolition and the inexpression dimensions of negative symptoms, as well as to social and verbal functioning. They hypothesized avolition and inexpression would be associated with less accurate pleasant odor identification across psychotic disorders. 

This study compared variations in symptoms and olfaction between 119 individuals with schizophrenia-spectrum disorder and 160 comparison participants. Data measures included demographic information, symptom variables, olfactory identification, and social/verbal functioning. Historical regression findings demonstrated that pleasant odor identification was associated with avolition, and unpleasant odor identification was associated with inexpression. Furthermore, the relationships were found to be transdiagnostic, because they did not differ across psychotic disorders. Linear regression models also determined that pleasant and unpleasant odor identification were significant predictors of verbal functioning. 

Overall, worse pleasant odor identification was associated with avolition and worse unpleasant odor identification was associated with inexpression, demonstrating olfactory dysfunction. The specificity of pleasant odor identification was also found to be a predictor of social functioning. Pleasant and unpleasant odor identification were significant predictors of verbal functioning, suggesting that multiple mechanisms are impacting language deficits in psychotic disorders. These findings expand on previous studies establishing close associations between olfaction, negative symptoms, and social functioning. Future studies should determine if olfactory functioning could be utilized as a low-cost marker for predicting and understanding the severity of certain negative symptoms. Such an identification could be beneficial to individuals with psychotic disorders by quickly identifying and ameliorating their negative symptoms; thus, improving their quality of life. 

Works Cited: 

[1] Larsen, E. M., Donaldson, K. R., Jonas, K. G., Lian, W., Bromet, E. J., Kotov, R., & Mohanty, A. (2022). Pleasant and unpleasant odor identification ability is associated with distinct dimensions of negative symptoms transdiagnostically in psychotic disorders. Schizophrenia Research, 248, 183–193. https://doi.org/10.1016/j.schres.2022.08.011 

[2] Image retrieved from: https://www.medicaldaily.com/how-does-nose-smell-inner-workings-our-sense-smell-324566