The Journal of Quality Research in Dementia, Issue 3 (lay summary)
Aromatherapy for the treatment of Alzheimer's disease
Professor Elaine Perry (FmedSci)
Professor of Neurochemical Pathology, Institute for Ageing and Health, Newcastle General Hospital, Westgate Road, Newcastle upon Tyne NE4 6BE Telephone 0191 444 4416. Fax 0191 444 4402. Email E.K.Perry@ncl.ac.uk Elaine Perry also runs Dilston Physic Garden, Northumberland (www.dilstonphysicgarden.com)
Linda Cawley, Secretary to the Cerebrovascular Group, Institute for Ageing and Health, assisted in the preparation of this article.
Essential oils have been used for centuries as a medicine. But there has been a lack of scientific evidence of whether aromatherapy really works. This is beginning to change, with a number of trials showing positive effects for people with Alzheimer's disease.
Aromatherapy is based on the theory that essential oils, derived from plants, have healing powers. The oils are generally:
- applied directly to the skin, often accompanied by massage
- heated in an oils burner to produce a pleasant odour
- placed in a bath.
A long history
Aromatic plant oils have been used for more than 5,000 years by many civilisations. The ancient Egyptians used perfumes and plant oils extensively for their effects on people, but also as offerings to gods. Indian and Chinese cultures both have long histories of using plant oils as medicine. The Greeks and Romans also used aromatherapy, with the Emperor Nero relying on rose oil to cure his headaches, indigestion and lift his spirits. Modern aromatherapy began in Germany during the 16th century, and more recently it was used to treat wounded soldiers in both World Wars I and II.
But does it work?
More trials have investigated the effectiveness of aromatherapy in dementia than in any other condition.
The best test of whether a treatment is effective is a controlled clinical trial. This tests the effect of a treatment by using two or more groups of people with the same condition. At its most basic, a controlled trial treats one group and uses another group as a control. This means that they do not receive the treatment, but usually receive instead a dummy treatment or placebo. Sometimes the researcher knows whether or not the treatment is real, but the patient doesn't (single-blind trial) and sometimes neither of them knows (double-blind trial).
Open trials are less structured and less likely to produce unbiased results than controlled trials. In open trials, the researcher knows the full details of the treatment, and so does the patient.
Open trials of the effect of aromatherapy for people with dementia have shown that the therapy can produce beneficial effects. For example, when lavender, geranium and mandarin essential oils (in an almond carrier oil) were applied to the skin of 39 patients, they showed increased alertness, contentment and sleeping at night, and reduced levels of agitation, withdrawal and wandering. More recently, an open trial that used a range of essential oils - such as ylang ylang, patchouli, rosemary, peppermint and others - resulted in a marked decrease in disturbed behaviour in the majority of people with dementia who participated. This resulted in their being prescribed fewer modern medicines.
Controlled clinical trials
So far, the most commonly used essential oils in placebo controlled clinical trials for the treatment of dementia have been lavender and lemon balm. Most trials have involved care home residents with advanced dementia.
The following controlled clinical trials have produced very encouraging results:
a) Lemon balm and lavender aroma were introduced to six patients and compared with sunflower oil for six others as controls for one week. The treatment increased functional abilities and communication, and decreased difficult behaviour.
b) Lavender aroma and massage with 21 patients were compared with aroma or massage alone for one week. Aromatherapy with massage significantly reduced frequency of agitation.
c) Lavender aroma was given to 15 patients as oil and placebo (water) on alternative days for 10 days. The aromatherapy significantly reduced agitated behaviour (as assessed using the Pittsburgh Agitation scale) versus placebo.
d) Lemon balm (Melissa) lotion was applied to the face and arms of 36 patients while another 36 patients had sunflower oil applied. Melissa was associated with highly significant reductions in measures of agitation (on the Cohen Mansfield Agitation Inventory) and social withdrawal, together with an increase in constructive activities (as measured by dementia care mapping).
e) Lavender, marjoram, patchouli and velvert were applied as a cream to body and limbs of 36 patients and compared with plain oil. The essential oil combination significantly increased scores on the Mini Mental State Exam, but also increased resistance to care (considered to be due to increase in alertness), compared with the plain oil.
It seems logical to suppose that aromatherapy works through a person's sense of smell. However, many patients with advanced dementia have lost their sense of smell. Research by in 2004 showed that lavender aromatherapy that was only taken in through the nose had no effect on agitation in people with dementia. In contrast, lavender applied as a skin lotion has been shown to be effective in some of the research listed above. A recent study from Korea showed that lavender hand massage reduced aggression in people with dementia.
Essential oils should be used with caution. If used appropriately, they are unlikely to cause side effects, making them a welcome alternative to antipsychotic drugs such as tranquillisers or the anti-depressents that are often used to treat agitation or other behavioural symptoms of dementia. In general, the essential oils that are used in aromatherapy carry the least risks possible to the user. Lavender is considered to be the safest oil to use, but others such as basil, chamomile, coriander, lemon, lemon balm and neroli are also generally safe.
We need to understand more about the basic science of aromatherapy. Essential oils contain chemicals called terpenes that can act as chemical messengers in the brain. More research is needed to discover exactly how the oils interact with our bodies and we need to identify the specific biological mechanisms that they affect. This is particularly important as aromatherapy can potentially affect all of the body's systems, so it is important to understand the precise impact that the oils have and whether there are any potential side-effects or chance of them interacting with conventional medications.
We also need to know what are the best strengths of oil to use. Controlled clinical trials can help improve understanding of what dose is needed to have a specific effect. Once this information is established it can be used to lay down standards of quality for essential oil manufacturers.
Overall, we need reliable evidence of whether aromatherapy can offer an effective treatment for Alzheimer's disease.
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Bowles-Dilys EJ, Griffiths M, Quirk L, et al. Effects of essential oils and touch on resistance to nursing care procedures and other dementia-related behaviours in a residential care facility. Int. J. Aromather. 2002; 12: 1-8.
Holmes C, Hopkins V, Hensford C, et al. Lavender oil as a treatment for agitated behaviour in severe dementia: a placebo controlled study. Int. J. Geriatr. Psych. 2002;17:305-8.
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