Leveraging Sense of Smell Could Help Treat Depression: Study

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Feb. 14, 2024 – People with depression who get stuck in negative thought cycles could potentially use their sense of smell to help manage their symptoms, according to a new study that prompted people to smell a dozen scents, ranging from coffee to ketchup. 

The findings were published this week in JAMA Network Open and showed that people with depression had more detailed memories when asked to smell something and then recall a personal memory, compared to when they were presented with a word and then asked to recall something related to the word from the past.

The study evaluated autobiographical memory, which refers to the ability to recall one’s own personal history. People in the study were instructed to recall specific memories, such as a visit to a coffee shop on a particular day.

The small study included 32 adults who had major depressive disorder. People were excluded from the study if they had psychosis, bipolar disorder, or a history of drug or alcohol abuse. Of the 32 adults, 26 were women, and the people in the study ranged from 18 to 55 years old.

Previous research has shown that people with depression are less able to recall specific memories, such as an event that occurred on a specific day. Even when a person recovers from depression, this reduced ability to recall memories or factual information about themselves persists, the authors noted, adding that the deficit can lower a person’s quality of life. Nearly 1 in 5 U.S. adults have been diagnosed with depression during their lifetime, according to the CDC.

For the study, people were asked to smell a total of 12 scents, and they were also given 12 words that described things that have distinct scents. After each word or scent was presented, the person was asked to recall a specific memory. The stimuli included Vicks VapoRub, ketchup, apple cider vinegar, red wine, lavender, and tobacco.

The people in the study described the odors as more arousing and vivid than the words, but their recall from the odors was slower. After smelling an odor, the average recall time was 14.5 seconds, compared to an average recall time of 8.9 seconds for a word cue. The researchers compared the performance of the people with depression to previously published general population performance, and the people with depression recalled fewer specific memories using words, but just as many specific memories using scents.

The findings are important because other research studies have linked improved memory specificity in people with depression to a reduction in their depression symptoms. This latest study could help guide development of a neurofeedback treatment for depression.

The brain processes smells in a way that may prompt more emotion along with memories, the researchers noted.

“If we improve memory, we can improve problem solving, emotion regulation and other functional problems that depressed individuals often experience,” researcher Kymberly Young, PhD, an associate professor of psychiatry at the University of Pittsburgh, said in a statement.