Emotional body odors may have the potential to enhance the anxiety reducing effects of mindfulness. This is shown by a pilot study published in the Journal of Affective Disorders, co-authored by researchers from Karolinska Institutet.
Body odors can serve as a means of social communication. Body odors, such as sweat, contain a cocktail of chemical processes (so-called chemosignals), which in turn are influenced by a person's emotional state. Studies indicate that individuals exposed to chemosignals from a person in a particular emotional state, such as fear or happiness, exhibit a certain replication of this state. This replication occurs unconsciously and has most often been observed through different physiological tests.
As most studies in this area have involved healthy subjects, the overall goal of this project was to study the potential benefit of chemosignals for individuals with psychiatric symptoms. The purpose of this study was therefore to investigate whether emotional body odors can enhance the benefits of a mindfulness-based intervention for individuals with social anxiety or depression.
"We know that humans are influenced emotional body odors, even if we are not consciously aware of it happening. In our study, we wanted to test whether this knowledge can be used to enhance psychological treatments", says Emma Eliasson , postdoctoral researcher at the National Centre for Suicide Research and Prevention (NASP) , the study's third author.
Exposed to happiness, fear, and clean air
A total of 48 women with symptoms of social anxiety, and 30 women with depression were recruited for the study. Participants were divided into three different groups exposed to either happiness body odor, fear body odor, or clean air. The participants were tasked with performing mindfulness exercises over two consecutive days, which included breathing exercises, meditation, and relaxation exercises. During the exercises, the specific body odor was introduced to each group.
Anxiety or depression levels were assessed at the beginning and end of each mindfulness session. At the same time, heart rate variability and electrodermal activity (via skin conductance) were recorded during the exercises to measure physiological stress indicators.
Significant reduction in anxiety levels
On the second day of the study, significant reductions in anxiety symptoms were observed for those exposed to happiness and fear body odors, compared to those exposed to clean air, where the effect of mindfulness was weaker.
"The results were quite surprising as we observed an enhanced symptom reduction for individuals with social anxiety that received chemosignals, regardless of whether they came from fear or happiness body odors. This may indicate that it is not the emotion itself that leads to the improved effect, but perhaps rather that chemosignals convey a kind of 'human presence'. However, this is something we need to study further.", says Emma Eliasson.
The results at a physiological level were also remarkable, as exposure to fear body odor compared to clean air resulted in lower heart rate variability. This indicated that fear body odor induced a less relaxed state on a physiological level, even though this was, notably, not reflected in the self-reported anxiety ratings. No significant differences were observed in electrodermal activity between the three odor conditions.
Moreover, no differences between the odor conditions were seen for the group with depressive symptoms, potentially indicating that body odors may not have the same benefits for depression. However, as this was only tested on 30 women, any conclusions drawn are limited.
Enhancing treatments with the help of body odor
Although the results suggest that exposure to body odors could be used to improve psychological treatments for anxiety, the researchers behind the project emphasize that this was a pilot study with a relatively small sample size.
"Although the results were encouraging regarding the potential to reduce anxiety, the main take-away is that that this needs to be investigated further, ideally through larger, more controlled trials. It is also important to clarify the mechanisms behind the potential ability of chemosignals to enhance the anxiety-reducing effect of mindfulness", says Emma Eliasson.
If these results are replicated and expanded on, they could hopefully pave the way for utilizing body odors within psychological therapies to enhance treatment outcome.
Publication
Cecchetto, C., Dal Bò, E., Eliasson, E. T., Vigna, E., Natali, L., Scilingo, E. P., Greco, A., Di Francesco, F., Hadlaczky, G., Lundström, J. N., Carli, V., & Gentili, C. (2024). Sniffing out a solution: How emotional body odors can improve mindfulness therapy for social anxiety. Journal of Affective Disorders, 369, 1082-1089. Advance online publication. https://doi.org/10.1016/j.jad.2024.10.088
