Mania can affect how a person thinks- but what about how a person smells? A study published in the Journal of Psychiatric Research suggests that people in a manic state may have difficulty identifying positive smells.
Bipolar disorder symptomology consists of depressive, manic, and hypomanic episodes. Mania can be associated with an increase in energy, mood, emotions, and/or activity in a way that is significantly different than an individual’s usual self. Manic episodes are associated with disruption in certain brain regions, including the amygdala, which also plays a role in processing scents. Issues with olfaction have been linked to other mental illnesses, such as depression.
The new study seeks to better understand the differences in olfactory functioning among people in manic episodes, people with bipolar disorder in remission, and healthy control individuals.
Researchers Francois Kazour and colleagues utilized 96 participants split into 3 groups: bipolar mania, bipolar in remission, and healthy controls. Participants in manic episodes were recruited from an inpatient psychiatric unit, while participants in remission were recruited from two outpatient treatment centers. Controls were recruited among visitors to a general hospital and were matched to the other groups based on age, gender, and smoking status.
To qualify for the remission group, participants had to be in remission for at least 3 months. Participants could be excluded for exhibiting psychosis, anosmia, substance use history, and use of medication that could affect smell. Participants completed a questionnaire containing demographic, medical, and psychiatric information. Participants were given a clinical evaluation, which included a neuropsychiatric interview, depression scale, manic symptom measure, anxiety inventory, and anhedonia scale. Olfactory functioning was measured utilizing tests that evaluate olfactory threshold, odor identification, and odor pleasantness and intensity.
Results showed that there were group differences in olfactory functioning between participants experiencing mania, participants with bipolar in remission, and participants without a mood disorder. Individuals experiencing mania had more difficulty identifying positive smells and rated the emotions associated with positive smells as lower than people with bipolar in remission and healthy controls.
Additionally, participants experiencing mania had higher emotional ratings for negative smells as compared to the other two groups. Both groups of participants with bipolar disorder showed impaired olfactory identification when compared to the controls, with participants who were manic showing increased deficits compared to those in remission.
This study took steps into understanding how olfactory deficits are related to bipolar symptomology. Despite this, there are limitations to note. One such limitation is that this study is cross-sectional. Future research could utilize a longitudinal design to see if olfactory deficits lessen and worsen through manic and remitted stages. Additionally, participants had significant differences in the number of depressive episodes they had, which could be a factor that serves as a confound.
The study, “Mania associated olfactory dysfunction: A comparison between bipolar subjects in mania and remission“, was authored by Francois Kazour, Boriana Atanasova, Marc Mourad, Charline El Hachem, Thomas Desmidt, Sami Richa, and Wissam El-Hage.