Aromatherapy in Dementia

In a consensus statement recently published by the British Association for Psychopharmacology,1 the use of aromatherapy as an adjunct to the pharmacological treatment of dementia is supported by one of the highest level of scientific evidence – evidence from randomized controlled trials.

A number of recent, controlled studies have shown that aromatherapy (the therapeutic use of pure plant essential oils) can be useful in the management of patients with dementia: lavender (Lavandula angustifolia or Lavandula officinalis) and lemon balm (Melissa officinalis) are two essential oils of particular interest in this area. The aim of the article by Holmes & Ballard,2 summarized here, was to review published reports of the efficacy of aromatherapy for the treatment of behavioural problems in people with dementia.

The results of these studies are interesting as their findings cannot be dismissed as merely resulting from the placebo effect of a pleasant-smelling fragrance: as the authors note, most people with severe dementia will have lost any meaningful sense of smell because of the early loss of olfactory neurons.3 Indeed, the pharmacological mechanism by which aromatherapy produces its effects is not thought to involve any perception of odour. Instead, the active compounds are thought to enter the body (by absorption through the lungs or olfactory mucosa) and be delivered to the brain via the bloodstream, where they elicit direct actions.

Aromatherapy studies in patients with dementia A large number of small, uncontrolled case studies have demonstrated the efficacy of inhaled and/or topical lavender oil in this setting. In summary, these studies have shown lavender oil to improve sleep patterns,4-7 and to improve behaviour.8,9

Although only a few controlled studies have investigated the potential use of aromatherapy for the management of behavioural problems in people with dementia, the results have been positive. A single-blind, case-controlled study investigated the effects of lavender essential oil on disordered behaviour in patients with severe dementia.10,11 Patients (n=21) were randomized to receive massage only, lavender essential oil administered as massage or lavender oil administered via inhalation plus conversation. Of the three patient groups, those receiving the essential oil in a massage showed a significantly greater reduction in the frequency of excessive motor behaviour.

In a small (n=15) double-blind, placebo-controlled, crossover trial in patients with severe dementia on an NHS care ward,11,12 2% lavender oil was administered in an aroma diffuser on the ward for a 2-hour period, alternated with placebo (water) every other day, for a total of ten treatment sessions. According to the group median Pittsburgh Agitation Scale score, treatment with lavender aromatherapy reduced agitated behaviour significantly (p=0.016) in patients with severe dementia compared with placebo, with 60% of patients experiencing some benefit. No adverse events were reported and compliance with therapy was 100%.

In a crossover study,13 56 elderly patients with moderate to severe dementia were massaged with a cream containing a blend of four essential oils (lavender, sweet marjoram, patchouli and vetiver) or cream alone five times a day for 8 weeks. Behavioural problems and resistance to care were significantly lower in patients who received the cream containing the essential oils compared with those who received the cream alone.

In the largest double-blind, placebo-controlled study published at the time this review was written,11,14 72 patients with severe dementia in NHS continuing care were randomized to receive either lemon balm essential oil (n=36) or sunflower oil (n=36) applied topically as a cream twice a day, in addition to patients’ existing psychotropic medication. Clinically significant changes in agitation (as assessed using the Cohen-Mansfield Agitation Inventory [CMAI]) and quality of life indices were compared between the two groups over a 4-week period of treatment. A 30% reduction in CMAI score was seen in 60% of the active treatment group and 14% of the control group. The overall improvement in agitation (mean reduction in CMAI score) was 35% in patients treated with lemon balm compared with 11% in those receiving placebo (pMethodological issues

In their article, Holmes & Ballard2 draw attention to a number of methodological issues that need to be considered in the design of future studies investigating the potential role of aromatherapy in the clinical treatment of behavioural and psychiatric symptoms in people with dementia.

Although most people with severe dementia have little sense of smell, the researchers assessing the study may be able to identify the essential oil being tested, which could compromise a double-blind study. This problem can be overcome in various ways, such as using observational measures as the primary outcomes of the study, supplying researchers with masks infused with fragrance or nose clips to wear when assessing participants, infusing the environment with control fragrances and masking the aroma of the essential oil with air fresheners.

In addition, as large placebo responses have been observed in many studies investigating the treatment of behavioural or psychiatric symptoms in people with dementia, it is important, in studies investigating the effects of essential oils, that the control and aromatherapy interventions involve similar amounts of time and touch with each participant.

Conclusions

Holmes & Ballard2 conclude that although there is much case-based evidence suggesting the efficacy of aromatherapy in improving sleep, agitated behaviours and resistance to care in dementia, there is a marked lack of adequately sized, placebo-controlled, randomized studies in this area. Although one placebo-controlled study has shown evidence that aromatherapy may be effective as adjunct to existing therapy in the management of patients with dementia, this study had a number of methodological flaws.

The authors identify a number of important issues that need to be addressed in researching the efficacy of aromatherapy in patients with dementia, including:

• Patients with different forms of dementia respond differently to pharmacological agents; whether the same is true regarding their response to aromatherapy remains to be determined.
• Essential oils are administered by massage in various ‘carriers’ (e.g. skin creams, massage oils), and therefore involve the ‘additional therapy’ of physical contact with carers. Clearly, this additional therapy needs to be minimised or controlled for before direct inferences can be made about the effects of aromatherapy alone.
• If it is accepted that there are active neurochemical differences between essential oils, then research should investigate not only the oils from different genuses but should also compare those from related species (e.g. Lavandula angustifolia and Lavandula officinalis).
• Properly conducted, well-designed, randomized, controlled trials are required before firm conclusions regarding the efficacy and safety of essential oils can be drawn.

References

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