Subjective assessment of the effects of an herbal supplement containing lavender essential oil on sleep quality: A randomized, double-blind, placebo-controlled crossover study

Figures & data

Figure 1. Diagram of the study design.

Table 1. Demographic information of study participants

	Study population (N = 51)
Age, in years (Mean, Range)	27.8, 19–55
Body weight, in pounds (Mean, Range)	161.4, 116–275
Ethnicity
Caucasian	33 (64.7%)
Asian	6 (11.8%)
Hispanic	11 (21.6%)
Undeclared	1 (2.0%)
Gender
Female	31 (60.8%)
Male	20 (39.2%)
Medication use* (non-sleep related)
Prescription medications	11 (21.6%)
Over-the-counter	4 (7.8%)
Natural supplements	31 (60.8%)
None reported	11 (21.6%)
Insomnia Severity Index (ISI)
8–14 (minor insomnia)	31 (60.8%)
15–21 (moderate insomnia)	18 (35.3%)
22–28 (severe insomnia)	2 (3.9%)

* More than one answer is allowed.

Table 2. Summary of Leeds Sleep Evaluation Questionnaire (LSEQ) data

	Active group, mean (SE of mean)	Placebo group, mean (SE of mean)	Difference between means (SE of difference)	F1, 144 value	p-value
Overall LSEQ	58.34 (3.11)	51.20 (3.11)	7.14 (2.63)	7.36	0.008*
Subcategory 1, getting to sleep (Q 1–3)	63.81 (3.04)	57.98 (3.04)	5.83 (3.10)	3.52	0.06
Subcategory 2, quality of sleep (Q 4–5)	57.10 (4.37)	51.32 (4.38)	5.78 (4.23)	1.87	0.17
Subcategory 3, awakening following sleep (Q 6–7)	55.67 (4.06)	45.33 (4.06)	10.35^§ (4.12)	6.29	0.01*
Subcategory 4, behavior following awakening (Q 8–10)	54.70 (3.65)	47.51 (3.65)	7.19 (2.96)	5.93	0.02
Ease of falling asleep (Q 1)	64.86 (4.12)	54.72 (4.12)	10.14^§ (4.08)	6.25	0.01*
Speed of falling asleep (Q 2)	63.35 (4.18)	55.72 (4.18)	7.63 (4.08)	3.48	0.06
Feelings of sleepiness (Q 3)	62.09 (3.56)	62.14 (3.56)	−0.05 (4.42)	0.00	0.99
Sleep quality (Q 4)	56.67 (4.20)	49.54 (4.20)	7.13 (4.68)	2.32	0.13
Less wakefulness (Q 5)	57.32 (5.12)	52.84 (5.13)	4.48 (4.63)	0.93	0.34
Ease of awakening (Q 6)	55.83 (4.25)	44.77 (4.25)	11.06^§ (4.32)	6.54	0.01*
Shorter time of awakening (Q 7)	55.43 (4.09)	45.92 (4.10)	9.51 (4.32)	4.84	0.03
Alertness after awakening (Q 8)	52.23 (4.75)	43.73 (4.76)	8.5 (3.95)	4.64	0.03
Alertness in general (Q 9)	51.81 (4.30)	46.23 (4.30)	5.58 (4.61)	1.46	0.23
Coordination after awakening (Q 10)	61.52 (3.48)	53.94 (3.49)	7.58 (3.04)	6.22	0.01*

Notes: SE, standard error; §, clinical significance (with a difference in mean of > 10)*, statistical significance (p ≤ 0.01).

Table 3 Summary of Insomnia Sleep Index (ISI) scores and significance of interaction with treatment

	Active group, mean (SE of mean)	Placebo group, mean (SE of mean)	Difference between Means (SE of difference)	t1, 144 value	p-value
ISI category 1 (mild insomnia, score 8–14)	52.03 (2.18)	52.15 (2.22)	−0.12 (1.84)	−0.07	0.95
ISI category 2 (moderate insomnia, score 15–21)	56.29 (3.13)	45.61 (3.12)	10.67§ (2.50)	4.27	0.0001*
ISI category 3 (severe insomnia, score ≥ 22)	66.70 (8.51)	55.85 (8.51)	10.85§ (7.25)	1.50	0.14

Notes: SE, standard error.

§ Clinical significance (with a difference in mean of >10).

* Statistical significance (p ≤ 0.01).

Table 4. Summary of data from the sleep diaries on a per night basis

	Active group, mean (SE of mean)	Placebo group, mean (SE of mean)	Difference between the means (SE of difference)	F1, 144 value	p-value
Total sleep (Minutes)	458.62 (10.47)	452.76 (10.48)	5.86 (8.62)	0.46	0.50
Sleep latency (Minutes)	45.22 (6.65)	47.46 (6.64)	−2.24 (3.80)	0.35	0.56
Number of waking events	1.07 (0.19)	1.17 (0.19)	−0.10 (0.11)	0.91	0.34
Waking duration (Minutes)	11.52 (2.45)	10.74 (2.45)	0.78 (1.88)	0.17	0.68
Sleep efficiency	0.89 (0.01)	0.88 (0.01)	0.01 (0.01)	0.70	0.40

Notes: SE, standard error. Sleep efficiency = total sleep time/total time in bed.