Lavender oil also had a positive effect on BPSD in another study. A placebo controlled trial with 15 participants with severe dementia using 2% lavender oil aromatherapy steam every second day for a total of 10 sessions resulted in 60% (n = 9) of participants showing improvement, 33% (n = 5) showed no change and 7% (n = 1) showed a worsening of agitated behaviour when compared to the control group [13]. This study was limited by the small sample size.
The largest aromatherapy study to date was a double-blind parallel-group placebeo-controlled randomised trial across 3 centres in the UK using melissa oil [14]. In this study 114 participants were allocated to 1 of 3 groups: placebo medication and active aromatherapy; active medication and placebo aromatherapy or placebo of both. The Pittsburgh Agitation Scale [15] and Neuropsychiatric Agitation Inventory [9] were completed at 4 weeks and 12 weeks follow-up. There was no evidence that melissa oil aromatherapy was superior to placebo or donepezil, an anticholinesterase, in reducing BPSD. There was a change from baseline to week 12 in quality of life (QOL), with the aromatherapy group experiencing the best outcome.
A number of small studies have also combined essential oils in the belief that this would improve outcomes. However, only one study has reported a significant reduction in agitated behaviours using a combination of essential oils including lavender, camomile, rosemary and marjoram [16]. Essential oils were provided in a footbath, massage on upper body and hands or on pillows. However, the findings were based only on observations. This study was further limited by the lack of blinding, small sample size and data collection undertaken by care staff [16]. In addition the application of aromatherapy by massage or touch, rather than inhalations may also confuse the findings as there is a small amount of evidence suggesting that massage and touch by themselves may influence BPSD