A new study published in the journal Scientific reports Emphasizes the complex connection between depression and the sense of smell. The study found that as odor perception improved, participants’ symptoms of depression decreased, especially among people with poor sense of smell.
The richness of research has shown a link between depression and olfactory function. For example, older people who have lost their sense of smell may develop symptoms of depression in the future. Interestingly, this approach seems to be two-sided, and patients with depression have a worsening sense of smell.
Studies have also shown that improving smell by training the sense of smell can improve mood, but it is unclear whether these benefits are due to greater exposure to odors during exercise or to self-improvement of sense of smell.
Leading researcher Agneska Sabinievich, a member of the Smell and Taste Clinic at Dresden University of Technology, said: “Given that depression is one of the most common psychiatric disorders, a comprehensive approach to its treatment would be useful.” “At the same time, people are experiencing olfactory dysfunction, mood swings, and many studies suggest a link between odor perception and depression. However, the nature of this connection still needs to be explored. ”
Sabiniewicz and his research team invented a study to determine whether an improvement in olfactory function coincides with an improvement in depressive symptoms. The study focused on patients with dysosmia, which is a disorder of olfactory function.
The sample consisted of 171 participants aged 14 to 87 years who attended the odor and taste clinic due to impaired sense of smell. According to the olfactory test, the majority of participants (157) reached the threshold of dysosmia, while a small minority (14) were considered to have a normal sense of smell.
Twice, at 11-month intervals, approximately each participant’s sense of smell was tested and their depressive symptoms were assessed. The olfactory function was assessed by odor threshold, odor discrimination, and odor identification tests, in which the scores of the three tests were collected as a measure of total olfactory function. The severity of depressive symptoms was assessed by a general-scale scale of depression.
The researchers then analyzed whether the changes in participants’ olfactory functions matched changes in the severity of their depressive symptoms. The results showed that the improvement in the severity of depression was associated with improved odor perception and overall olfactory function, especially among patients with dysosmia. It should be noted that participants with dysosmia showed improved odor detection, which is five times stronger than the whole sample.
“Numerous scientific studies have shown that there is a link between odor perception and depression,” Sabinievich told PsyPost. “This communication has led to practical efforts to improve the sense of smell, that is, the frequent exposure to odors. Although this method has been successful, our study is the first to show that the sense of smell may be directly related to mood. In other words, people with improved sense of smell, who did not have the ability to smell, showed a decrease in depression. This is an interesting discovery that allows us to expand the connection between the sense of smell and depression. ”
There are various theories about the connection between the sense of smell and depression, but some studies suggest that this connection is due to the general connections in the brain. Smell information travels through many areas of the brain, and it also plays a role in affective functions, such as the processing of emotions. These areas include the amygdala, hippocampus, and anterior cingulate cortex.
Among the limitations, the study authors acknowledge, was that the sample they visited consisted of people who had a treatment center who sought help for olfactory impairment. Thus, participants may show more signs of depression than people with olfactory problems who do not seek counseling.
“For people seeking clinical advice, odor disturbances usually cause emotional distress,” Sabinievich explained. “Thus, this study model probably showed depressive symptoms compared to other people with odor disorders who did not feel the need for treatment.”
“Symptoms of depression change with olfactory function,” a study by Agneska Sabinievich, Leonie Hoffman, Antje Gahner, and Thomas Hummel wrote.