Smelling familiar smells could help improve mood in people suffering from major depression, a new study suggests.
Neuroscientists at the University of Pittsburgh found that patients who smelled 12 recognizable aromas had better access to positive memories, stopping negative thought patterns that perpetuate mental illness.
Participants recalled specific memories from their lives when they smelled Vicks Vaporub, coffee, vanilla extract, lavender hand soap, and more common household items.
Problems with autobiographical memory are a hallmark of major depressive disorder, which often causes patients to focus only on negative events or interpret them in negative ways.
Scientists say that by helping depressed people access their memories more effectively through smell, negative thought cycles can be intercepted.
Coffee is among one of 12 different smells that evoke memories, which can change negative thought patterns, researchers suggest.
Each odor presented to participants was associated with a corresponding word. For example, the word for cumin powder was “curry.” Researchers found that smells, not words, evoked the most vivid autobiographical memories.
For their study, the neuroscientists recruited 32 people between the ages of 18 and 55 with major depression. They were exposed to 12 odors in airtight jars along with a written cue about the odor.
The aromas included coconut oil, cumin powder, clove bulbs, red wine, shoe wax polish, vanilla extract, ketchup, and orange essential oil.
With their eyes closed, they sniffed each jar and were asked to consider a memory triggered by the smell.
Each participant rated the memories based on how good or bad it made them feel, how exciting it was, how clear it was, and how often they thought about it. They were then asked to identify each scent, but were told that it was not important to get it right.
Participants identified the odors correctly about 29 percent of the time on average. Smells evoked more specific memories of their lives than words. For example, hearing the word “menthol” was much less evocative than opening a bottle and smelling Vicks Vaporub.
Memories triggered by smell tended to be more emotionally arousing, more vivid, and took longer to remember than memories triggered by words.
The researchers said: “Memories evoked by odors may be unique relative to other stimuli, such as auditory and visual, and contain emotionality.”
The olfactory bulb, responsible for processing odors, connects directly to key regions of the brain associated with memory and emotions, such as the amygdala and hippocampus.
Unlike other senses, smells can directly access the emotional part of the brain, which experts believe may explain why smells have such a profound impact on our memories and emotions.
Dr. Kymberly Young, a neuroscientist and co-author of the study, said, “If we improve memory, we can improve problem solving, emotion regulation, and other functional problems that depressed people often experience.”
There are some approaches to treating depression that include scents to evoke positive memories.
Therapists can include aromatherapy as part of their normal cognitive behavioral therapy practice that trains depressed people to rethink their negative thought patterns.
They can also try what is known as reminiscence therapy, which involves remembering and sharing past experiences facilitated by sensory stimuli such as smells, photographs or music. The idea is that by tapping into memories and positive emotions, reminiscence therapy can improve mood, self-esteem, and overall well-being.
The findings were published in the journal. Open JAMA Network.