Why scents are being used to treat dementia and depression

Aromatherapy offers a gentle yet powerful tool for enhancing mental health and easing medical treatment anxieties. Photo / Getty Images

Doctors are harnessing our sense of smell to reignite positive memories and reduce anxiety.

One of my favourite places growing up was my grandmother’s rose garden (a refuge during heated family arguments). Even today, when I’m feeling stressed, I inhale a few drops of rose essential oil, and I’m back in that garden.

As a sense, smell is still much under-appreciated. No other sensory system has as much emotional and evocative potency, says Professor Rachel Herz, a cognitive neuroscientist and leading expert on the psychological science of smell. “Our sense of smell is processed in the same part of the brain as our emotions and emotional memories. So upon smelling something, if there’s a prior association, it instantly activates the emotion of that association.”

Our sense of smell tells us where it is safe to live, helps us find food, helps us choose the right partner and recognise our own child. “Smell has been an essential survival mechanism for humans over the course of 1.5 million years,” says Professor James Goodwin, the director of science at the Brain Health Network and the author of Supercharge Your Brain. And having a well-functioning sense of smell is really important for our mental health.

Scent can help treat depression

In February, a landmark study by neuroscientists from the University of Pittsburgh revealed smelling familiar scents can help improve mood in people suffering from depression. For their study, the researchers enrolled 32 people aged 18-55 with severe depression. They were exposed to 12 smells in airtight jars along with a written clue as to the scent.

The participants recalled specific memories from their lives when they smelled Vicks VapoRub, coffee, wax shoe polish, vanilla extract, lavender hand soap, and more common household items. It turned out smells evoked more specific memories from their lives than word cues.

Problems with autobiographical memory are a hallmark of major depressive disorder, explains Dr Kymberly Young, the co-author of the study, which means patients focus only on negative events or interpret events in a negative light. But smell-triggered memories tend to be more clear and “real” and more effective at triggering positive events, which can interrupt negative thought patterns. “If we improve memory, we can improve problem-solving, emotion regulation and other functional problems that depressed individuals often experience.”

Smelling familiar scents can significantly improve mood in people with severe depression, a University of Pittsburgh study found. Photo / 123RF

Calms patients undergoing cancer treatment

Many of us use lavender on our pillow to help with stress and insomnia. “Lavender is an analgesic, so it reduces pain. It is also proven to be anxiolytic, so it dissolves our anxieties,” says Goodwin. These soothing properties can be just as helpful in clinical settings.

Aromatherapy is increasingly being used in the treatment of cancer and end-of-life care. In her book Integrating Clinical Aromatherapy in Palliative Care, Carol Rose, a clinical aromatherapist and registered nurse, explains how patients can be involved in the process of choosing oils and applications, alongside conventional medical options. Massage, nighttime inhaler sticks, hydrosol mouthwashes and aromatic bathing help to treat fatigue, insomnia, breathlessness, nausea and foster resilience.

When a friend was going through cancer treatment, I asked perfume “nose” Lyn Harris, the founder of fragrance brand Miller Harris and Perfumer H, to make up a scent that would ward off the smell of chemo. My friend sprayed her scarf liberally with a blend before chemo sessions, and swears it got her through treatment.

Prompts memory in dementia patients

Most excitingly, aromatherapy can help patients living with dementia, says Goodwin, who is a big believer in the power of essential oils which can permeate the brain and produce powerful chemical changes to our mood. “Normally, the cells of the blood vessels in the brain are meshed very tightly to stop substances passing through what’s called the blood-brain barrier. But essential oils are very small aromatic molecules that evaporate easily into the air and can be breathed in. They enter the general circulation and pass into the brain.”

There is scientific evidence that lavender oil can reduce occurrences of aggressive behaviour in dementia. But a host of essential oils can be used for the treatment of Alzheimer’s. “In dementia patients, amyloid beta protein (amyloid plaques) accumulates between the cells, and we know that 6-Gingerol (ginger) reduces amyloid accumulation. Coriander, like lavender, can be used to reduce agitation. Rosemary improves concentration. Sweet orange, sandalwood, rose and bergamot also help to dissolve anxiety. Peppermint can bolster acetylcholine, a transmitter that plays a role in memory, learning and attention.” He advises families of dementia patients to use essential oils when massaging their hands and feet, add them to a bath, or heat them in an oil burner as a mood lifter.

Testing for loss of smell is actually a fairly reliable way of finding out if a patient has Alzheimer’s, reports Goodwin. “There’s a case for introducing a regular smell test which is clinically very easy to do. It works because loss of smell, a neurophysiological process, mirrors neurodegeneration generally in the brain.”

Lavender oil, known for its calming effects, has been scientifically proven to reduce occurrences of aggressive behaviour in dementia patients. Photo / 123RF

Soothes us before surgery

The science of smell is also making huge inroads into other areas of medicine, helping patients manage stressful situations, such as surgery and MRI scans. In January, Angel Houston, an MRI tech at Cleveland Clinic who performs cardiac MRIs, presented her research at the Society for Cardiovascular Magnetic Resonance meeting in London. She has developed a stress/anxiety reduction technique using aromatherapy for patients undergoing MRIs in place of sedation with Xanax.

Houston lost her brother at just 45 to cancer. Prior to his diagnosis, he went through countless examinations and prescription medications. Watching her brother’s medical journey made her think about other options that wouldn’t impact his awareness and sense of control. Houston’s research focuses on how aromatherapy can enable stress reduction without sedating effects, allowing the patient to remain alert and in control. The patient experience has been very positive, with many reporting significant reduction in their claustrophobia and anxiety with aromatherapy.