Could Olfactory Therapy Help Patients with Depression?

Multiple studies have shown that people with depression have trouble recalling specific memories. They might hear the word "party," for instance, and think, "I don't get invited to parties often." By contrast, someone without depression could hear the word "party" and immediately recall a childhood birthday or recent celebration at a friend's house. "It's not that depressed patients don't have memories; it's that they're having trouble accessing them," said Dr. Kymberly Young, an associate professor of psychiatry at the University of Pittsburgh.

Dr. Young published a study earlier this year in JAMA Network Open suggesting that familiar scents could help unlock these memories. Dr. Young and her team found that people with depression were able to recall specific memories more easily after smelling scents (such as ground coffee or tobacco) than just hearing a verbal cue (such as the word "coffee" or "cigarette"). Around 68% of the participants could recall specific memories in response to the odors, whereas only 52% could recall specific memories after hearing words out loud. In addition, the memories triggered by smells were also more vivid than memories triggered by words.

Being able to recall specific memories "is associated with better problem-solving skills and better emotional regulation," Dr. Young said. She added that the findings suggest that smell therapy could help people with depression avoid overthinking. That could help depressed individuals shake negative thought cycles and rewire their thinking patterns, the researchers noted.

There is already a well-established link between losing one's sense of smell and depression. A reduced sense of smell could increase the risk of depression, especially late-in-life depression. In a survey of more than 300 people who reported some smell loss due to COVID, 43% of participants said they felt depressed. Dr. Vidya Kamath, a neuroscientist from Johns Hopkins Medicine, said, "We think about reduced smell ability being associated with poor quality of life, poor hygiene, increased loneliness, as well as weight loss. All of those things are pathways by which we think about poor smell being linked to depressive symptoms."

Dr. Michael Leon, professor emeritus of neurobiology and behavior at the University of California, Irvine, said that the olfactory system (the body structures, including the nose, that regulate smell) communicates directly with the limbic system, a brain region associated with mood and memory. "The olfactory system is the only sensory system that has a direct, superhighway access to the memory centers of the brain and the emotional centers of the brain. All the other senses have to take the side streets to get there," Dr. Leon said. As a result, smells are more strongly linked to how people process emotions or recall past events compared with other senses like sight or sound.

Aromatherapy (a practice that utilizes the inhalation of essential oils to promote well-being) has gained attention for its potential in alleviating depressive symptoms. Additionally, olfactory training - a technique that involves regularly exposing oneself to a variety of scents - has shown promise in improving olfactory function and, by extension, potentially influencing mental health outcomes. The interconnectedness of our senses and mental health is a fascinating area of study, and the link between the sense of smell and depression adds another layer to our understanding. As research continues, we must acknowledge the potential impact of olfactory dysfunction on mental well-being and explore innovative therapeutic approaches that harness the power of scents.