Scent Therapy May Ease Depression by Improving Memory
[ad_1]
A familiar scent might help people with depression recall specific memories and potentially improve their symptoms, according to a study published February 13 in JAMA Network Open.
“Our key takeaway from this study is that people with depression have memories, they just have trouble accessing them. Odors could be one way to help these individuals improve their memory recall,” says the study’s senior author, Kymberly Young, PhD, a neuroscience researcher and an associate professor of psychiatry at the University of Pittsburgh Medical Center.
The findings also suggest that smells are more effective than words at bringing up a memory of a specific event, and could even be used in therapy to help depressed individuals get out of negative thought cycles and rewire thought patterns, according to the authors.
“This is a terrific study from a strong group with a track record of excellent memory research in adults with depression,” says Daniel Dillon, PhD, an associate professor of psychiatry at Harvard Medical School in Boston who was not involved in this new research. This may be the first study to use olfactory cues to trigger autobiographical memory retrieval in major depressive disorder, and the results are encouraging, says Dr. Dillon, who is a leading researcher in the role of memory in depression.
The Link Between Depression and Memory — and Why It Matters
The kind of memories investigated in this study are explicit memories, which is what people typically mean when they refer to “memory” in the everyday sense — specifically, episodic memory, or recalling discrete events in your life, he explains.
There are a few reasons why this type of memory is important, says Dillon. “We can use them to make smarter choices going forward, and we can use positive memories to regulate our emotions and repair our moods. In some cases, we can use negative memories to do the same. For example, remembering a past failure to help us try harder or stay on track better now,” he says.
There are also some cases where retrieval can be a problem, if we’re automatically recalling highly negative and intrusive memories, he adds.
Our Brains Are Wired to Connect Scent to Memory
Given this information, investigators aimed to find out whether engaging the amygdala could help depressed people access their memories more effectively.
Researchers Compared the Effectiveness of Word Cues and Scent Cues in Memory Recall
The study included 32 individuals between 18 and 55 years old with a primary diagnosis of major depressive disorder (MDD). Participants could be taking an antidepressant as long as they had been taking a stable dose of their medication.
A total of 24 items, half word cues and half odor cues, were presented to the participants. For the odors, study participants were exposed to different scents with their eyes closed. The strong familiar scents ranged from oranges to ground coffee to shoe polish, and even Vicks VapoRub.
Participants were asked to recall a specific memory from their life, good or bad, in response to each cue. Prior to odor exposure, participants were instructed and presented with the following example of a specific memory: “If the word ‘bold’ made you think of the fact that you tend to go to your local coffee shop every morning, that would not be a specific memory because it’s not a single event. Instead, you would want to think of a particular morning that you went to your local coffee shop.”
Researchers were surprised to discover that memory recall was stronger in depressed individuals who received odor cues as opposed to word cues. Those who received odor cues were more likely to recall a memory of a specific event (for example, that they went to a coffee shop last Friday) than general memories (that they have been to coffee shops before).
The memories spurred by odors tended to be much more vivid and felt more immersive and real. Interestingly, an odor cue was more likely to make participants remember positive events, even though they were not specifically directed to recall positive memories, according to the authors.
Findings Could Be Used in Current Treatments for Depression
The fact that when depressed adults were given odors cues, their ability to retrieve specific memories was better, is a novel and important finding on its own, and it suggests that it might be clinically useful: Odors might be used to help (or train) depressed adults to retrieve more specific memories, says Dillon.
Dr. Young agrees, and says that typically, the current treatments for depression that focus on increasing specific-memory recall ability use words to cue memories, whereas this study suggests that odors might be more effective.
“If we improve memory, we can improve problem-solving, emotion regulation, and other functional problems that depressed individuals often experience,” she says.
Why Do Different Cues Like Smells, Sights, Words, or Music Trigger Memories?
Any event that you experience will trigger activity in multiple brain regions, and when the event is stored in memory, the pattern of activation across those different brain regions is also stored, says Dillon.
“When it comes time to retrieve that memory, a cue can be very helpful because it can re-instantiate part of the pattern of activation that was elicited in the first place,” he says. That can lead to a ripple effect where one region activates another region, and so on until all the brain regions that “encoded” the memory are activated again and you experience the memory, says Dillon.
Can Tapping Into Everyday Scents Improve Our Mood?
Given that many of the odors used in the study were everyday smells, could people tap into this in their day-to-day life simply by being more mindful of what they’re smelling? Absolutely, says Young. “Taking time to appreciate smells and thinking of the memories they bring to mind could be a way to boost mood more generally,” she says.
The only downside is that negative memories could be triggered by smells, which could be distressing for some individuals, says Young.
Dillon says that people could “definitely” use these findings to retrieve memories. “As the paper points out, none of the smells used here were exotic, and our memories are being cued to odors, sounds, and sights all the time,” he says.
The key is to be mindful, says Dillon. “Most of this retrieval is done when we’re on autopilot, but if a depressed adult (or anyone who wants to improve their memory) wanted to hone their memory retrieval ability, they could be more attentive to the cues in their environment, the memories those cues elicit, and whether or not those memories are specific,” he says.
[ad_2]
