Disruption in your sense of smell could be linked to depression and emotional processing

The research was highlighted at the Minoritised Life Scientists Future Forum (MLSFF26) at Edinburgh International Conference Centre from March 23 to 25. MLSFF26 is the only major conference in Europe dedicated to supporting and showcasing the contributions of marginalised and underrepresented communities in the life sciences. 

Sofiia’s review investigated whether olfactory impairment (loss or reduction of the ability to smell) affects emotional processing in humans.

To evaluate effects on emotional processing, neuroimaging studies were considered alongside affective disorders as an extreme manifestation of mood, with a particular focus on depression. This secondary research found activity in neural regions shared between olfactory and emotional processing has been decreased in individuals with smell loss. There is also consistently reported association between olfaction and depression. It is important to highlight that current evidence reports correlation, and causation cannot yet be claimed.

“Olfaction is often overlooked. It is commonly chosen as the sense people would give up if they were to lose one of their five senses, and for most individuals, it goes largely unnoticed in daily life. However, it takes part in many aspects of human life, and its dysfunction has been reported to be associated with reduced quality of life and increased depression,” Sofiia explained. 

“Despite this, the mechanisms explaining the role of olfaction in emotional and cognitive processes remain unclear. Researching the mechanisms underlying olfactory processing, specifically whether they directly impact emotional regulation and cognitive function, has the potential to bring new approaches to managing affective disorders, cognitive decline, and overall wellbeing.”

The study was conducted as a literature review, with key limitations being time constraints and limited existing literature. PubMed database has been used as a primary source of literature and published studies. Findings from neuroimaging studies, psychological assessments, and review articles were evaluated. 

Affective disorders have been taken as a measure of emotional state effect. Olfactory training - repeated exposure to odours – effect has also been considered to assess whether improvements in mood could occur alongside improvements in olfactory function.

This study aimed to examine evidence of olfactory dysfunction impact on emotional processing in humans, with a particular focus on depression.

The evidence showed association of olfactory impairment and disrupted activity in the hippocampus and amygdala - key brain regions involved in both olfaction and emotional processing. Additionally, there is a consistent correlation between individuals with olfactory dysfunction and depression reported across studies. Although the strength of this relationship is debated, most studies show statistically significant values. Importantly, olfactory training improved depressive symptoms in individuals with subclinical depression, suggesting therapeutic potential.

“Before starting this research, I expected olfaction to be a niche area with very limited available evidence. Although I initially struggled to find relevant studies, I was surprised to discover clear identification of key brain regions involved in olfactory processing and eventually enough studies to research my topic of interest,” Sofiia said. 

“What I also found is that since COVID-19 olfaction’s recognition as an important area of study has increased.  This gave me hope that my dream research area is worth pursuing, and not as useless or overlooked as I previously believed.”

The findings suggest that olfactory dysfunction is not just a surface-level issue causing minor discomfort, such as a tolerable inability to smell perfumes or food consumed. It may, however, play an important role in emotional regulation and mental health. 

“The real-world applications of the research in this area expand towards the potential use of olfactory testing as a non-invasive tool for early detection of conditions such as depression, Alzheimer’s disease, and Parkinson’s disease,” Sofiia said. 

“Considering olfactory training showed a reduction in depressive scores, the potential of such therapy should be further explored in the hope of improve mood of populations who would benefit most.”

This research was limited by time constraints and scope, and further work is needed to clarify the reasons behind the links seen. 

Sofiia said she would focus future research on exploring the underlying molecular mechanisms associating olfaction with emotional and cognitive processing. 

“This should help determine whether the observed relationships are causal. It would also be extremely impactful to explore the role of olfactory dysfunction as an early biomarker for neurodegenerative diseases in more depth. Many studies, in fact,  already focus on this, and insights into the reasons for these correlations are being sought.”

This study was conducted independently. Sofiia expressed her interest in connecting with experts in the field for further discussion and potential collaboration opportunities.

Sofiia is also among the founders of the Society of Applied Sciences (SAS) at UWE Bristol, who were very excited to be represented at MLSFF. 

“I’m grateful to the active members who spoke with me during my research, as those conversations helped shape both the topic and the direction of the review,” she said.

“We are also planning an annual meeting in the 2026/2027 academic year for students interested in research, including BSc, Master’s, and PhD students, as well as graduates from all over the UK. If anyone would like to get involved and hasn’t yet filled in our expression of interest form, they are very welcome to contact us at [email protected].”