By David Kiefer, MD, Editor

Clinical Assistant Professor, Department of Family Medicine, University of Wisconsin; Clinical Assistant Professor of Medicine, Arizona Center for Integrative Medicine, University of Arizona, Tucson

SYNOPSIS: Lavender oil aromatherapy demonstrated some benefits in sleep and anxiety for people undergoing chemotherapy.

SOURCE: Özkaraman A, et al. The effect of lavender on anxiety and sleep quality in patients treated with chemotherapy. Clin J Oncology Nursing 2018;22:203-210.

EXECUTIVE SUMMARY

  • Seventy people with cancer and pending chemotherapy were randomized to aromatherapy with lavender oil, tea tree oil, or neither (the control group).
  • Surveys exploring anxiety and sleep were given to the participants at baseline and after completing chemotherapy and, in the intervention groups, one month of nightly home aromatherapy treatments.
  • There were no benefits in short-term anxiety, but lavender oil aromatherapy benefited chronic anxiety and sleep over the treatment period more than the control group or tea tree oil aromatherapy.

In the search for the safe and effective use of essential oils, there is some guidance in the medical literature. Most of the human studies have explored the use of essential oils in aromatherapy, and this clinical trial is no exception. The authors chose lavender oil (Lavandula angustifolia, Family Lamiaceae, flowers) aromatherapy for this intervention, due to the known GABA-nergic, and hence relaxing, effects of lavender, which has been well-supported by numerous prior clinical trials.1-4 Interestingly, one of the studies1 was in a similar demographic as the current clinical trial, namely, the use of lavender aromatherapy in people undergoing treatment for cancer. The authors, through a thorough literature review in their introduction, make a compelling case for the need for anti-anxiety and sleep-promoting treatments during cancer therapeutics.

The study took place in Turkey; although not expressly stated as such, all of the authors work at universities in Turkey. The researchers recruited adults with cancer who were about to receive their first series of outpatient, weekly chemotherapy treatments with paclitaxel (other chemotherapeutic agents also could be used). The recruits had to have a sense of smell to be included. The type of cancer was variable (but mostly breast cancer) as mentioned in their demographics table, though the staging was not detailed. People were excluded from the study if they had a chronic disease (cardiovascular disease and asthma were singled out) or a psychiatric diagnosis (including anxiety), were taking a medicine for anxiety, or if they had a “known history of allergy.” It is unclear if that meant a known history of allergy to lavender.

The participants were randomized to either aromatherapy with lavender (n = 30) or tea tree oil (n = 20) (in bottles with numbered labels), or a control group (n = 20) who received no aromatherapy. Both the patient and the administering nurse were blind to the treatment bottles, which arguably was compromised as soon as the bottles were opened. The researchers purchased the two essential oils from the same reputable and quality-controlled company; they chose tea tree oil as a placebo due to the lack of sedative properties. For the intervention, three drops of the oil were placed on a cotton ball that was set 10 inches below the nose near the neck and shoulders during each chemotherapy treatment of the “first cycle,” which presumably referred to a series of treatments but was not specified by the authors. In addition, for one month after the cessation of chemotherapy, participants were instructed to smell the oil for five minutes at 9 p.m. It was unclear whether cotton balls were used again or the participants simply opened the bottled and inhaled.

The researchers collected demographic data from the participants, and then measured anxiety and sleep with the State-Trait Anxiety Inventory (STAI; in two parts, S-Anxiety and T-Anxiety) and Pittsburgh Sleep Quality Index (PSQI), respectively, as per Table 1. Just before the first chemotherapy treatment and after completion of chemotherapy, all three of the tests (S-Anxiety, T-Anxiety, and PSQI) were administered. There is some confusion in the text about when the second testing occurred; that information likely was collected one month after the last chemotherapy treatment, after one month of nightly home aromatherapy treatments.

Table 1. Anxiety and Sleep Surveys

Name

Subset
(if applicable)

Scale

Comments

State-Trait Anxiety Inventory (STAI)

S-Anxiety (State)

1 (never) – 4 (always) for 20 short statements (80 points possible)

Focuses more on temporary anxiety

State-Trait Anxiety Inventory (STAI)

T-Anxiety (Trait)

1 (never) – 4 (always) for 20 short statements (80 points possible)

Focuses more on chronic anxiety

Pittsburgh Sleep Quality Index (PSQI)

N/A

Open-ended and multiple-choice questions; answers range from 0-3 for 7 components (21 points possible)

Lower scores indicate better sleep

The authors mention that the study participants were “homogenously distributed across groups,” and this appears to be supported by a demographic table that shows similarities in age (median 57-58), gender (more females than males), education (mostly primary school), marital status (majority married), and income.

Outcome results are shown in Table 2. For S-Anxiety, there was no change from the first to the second assessment for any of the groups, nor was the level of anxiety different between the groups. For T-Anxiety, the authors state similarities between the groups at baseline, but an improvement (P = 0.003) between the time points, and a statistically significant intergroup difference (P < 0.001). Looking at the numbers in the table, this conclusion seems unlikely, so one doubts the validity of their statistics. They do describe that most of the time difference stems from the lavender group (44.8 improving to 40.8) and the intergroup difference is due to the lavender post-chemotherapy (40.8) vs. the tea tree post-chemotherapy (45.2). For PSQI, both the lavender and tea tree aromatherapy groups improved over time (P < 0.001), but the control group did not. The authors state a significant intergroup difference, but it is unclear what that refers to; the only clarifying prose conveyed is that the second assessment for lavender was different than the second assessment for the control group.

Of note, no details were provided for adverse effects or participants who may have dropped out of the study.

Table 2. Survey Results for Baseline and Post-Chemotherapy

Group

S-Anxiety

T-Anxiety

PSQI

Lavender: baseline

41.4

44.8

7.6

Lavender: post-chemo

42.4

40.8

3.9

Tea tree: baseline

45.3

45.4

9.2

Tea tree: post-chemo

45.3

45.2

5.9

Control: baseline

42.0

45.4

7.05

Control: post-chemo

42.4

45.25

7.15

S-Anxiety and T-Anxiety from the State-Trait Anxiety Inventory. PSQI: Pittsburgh Sleep Quality Index

The three primary significant differences (variable P values) are in bold.

COMMENTARY

Methodologically, this study was less than ideal. However, if we look past those flaws, there may be some clinical insight relevant to treating people with anxiety and insomnia as they progress through chemotherapy and afterwards. In order to accept these results, we are assuming that no participants dropped out of the study, took any sleeping medicine (anti-anxiety medicines were prohibited), and adhered to the nightly aromatherapy treatments (unless they were in the control group). If this is the case, then there was a benefit of lavender oil aromatherapy in trait (or long-term) anxiety and sleep. The lavender anxiety effects were above-and-beyond benefits seen with tea tree oil aromatherapy and the control group, whereas the lavender sleep effects were only statistically significant when compared to the control group. This is notable, and potentially a useful adjunctive therapy for a demographic already facing treatment challenges through cancer therapy.

If we add a follow-up study to our wish list for anxiety and insomnia treatment options, it might be useful to review the flaws in this clinical trial. Perhaps the next set of researchers will keep these in mind in future study designs. For this study, the description was a little difficult to follow. Some basic tenets of a clinical trial publication were lacking, such as the actual process of recruitment, specifics of diagnosis, and corroboration at study conclusion that patients did not know which group they were assigned to (which is difficult given the olfactory clues from essential oils). Such unblinding certainly could have affected the final results. In fact, this might explain why there was a response in the sleep survey to the tea tree oil group; there should not have been any improvement in sleep, since tea tree oil does not have anti-anxiety or other relaxing effects. Perhaps the ritual of going through an aromatherapy explains some of the benefits seen, which was lacking in a control group with participants who did not have that ritual. Another question about the methodology is that why, if randomization was used, was there such a disparity in numbers in each of the groups? In addition, the exact method for administration of the aromatherapy at home was not described. All of this information is necessary to apply these results in clinical practice or to consider replicating the study in a follow-up clinical trial. Finally, as we ponder the potential benefits of the treatment intervention, it is imperative to know whether there were any observed adverse effects or plant-pharmaceutical interactions. For example, the author of this review can attest to at least one patient in his panel who has an allergic reaction to lavender, even in aromatherapy form.

Assuming a favorable safety profile, for patients going through chemotherapy, especially those with insomnia or chronic anxiety, it certainly can be worth considering lavender aromatherapy if it is permitted in the clinic or hospital setting, and if the patient would agree to home treatments after cessation of chemotherapy. The ritual and the physiological effects may indeed combine to benefit pre-existing anxiety or sub-standard sleep and contribute to overall health through the cancer treatment process.

REFERENCES

  1. Blackburn L, et al. The effect of aromatherapy on insomnia and other common symptoms among patients with acute leukemia. Oncol Nurs Forum 2017;44:E185-E193.
  2. Chien LW, et al. The effect of lavender aromatherapy on autonomic nervous system in midlife women with insomnia. Evid Based Complement Alternat Med 2012;2012:740813.
  3. Lewith GT, et al. A single-blinded, randomized pilot study evaluating the aroma of Lavandula augustifolia as a treatment for mild insomnia. J Altern Complement Med 2005;11:631-637.
  4. Lillehei AS, et al. Well-being and self-assessment of change: Secondary analysis of an RCT that demonstrated benefit of inhaled lavender and sleep hygiene in college students with sleep problems. Explore (NY) 2016;12:427-435.