The Therapeutic Effect of Aromatherapy on Insomnia: a Meta-Analysis

Highlights

• The pooled results of the meta-analysis showed that aromatherapy significantly improved the clinical symptoms of patients with insomnia compared with the control group.

• Inhaling aromatic substances, rather than using aromatic substances for massage could obviously improve the quality of sleep.

• The results of the subgroup analysis of the intervention duration indicated that different intervention duration does not seem to have a significant effect on the efficacy of aromatherapy.

Abstract

Background

: Insomnia is a more and more common sleep disorder, which affects health and quality of life. Aromatherapy is one of the effective treatments to improve sleep quality. This paper is to comprehensively evaluate the existing research on aromatherapy as a treatment of insomnia to verify its therapeutic effect.

Results

: 16 studies (19 comparisons) met inclusion and exclusion criteria were used for meta-analysis. The results showed that aromatherapy had a significant effect on improving sleep quality (WMD: -2.52; 95% CI: -3.24 to -1.79). Subgroup analysis showed that different types of patients from different countries can improve their sleep quality through aromatherapy. The inhalation group, rather than the massage group had an obvious therapeutic effect, which may be due to the number of studies using massage included in our analysis is too small. What's more, different intervention duration does not seem to have a significant effect on the efficacy of aromatherapy.

Conclusion

: Aromatherapy has a significant effect on improving sleep quality. It can be used as one of the non-pharmacological treatments for insomnia, and relevant guide should be formulated to facilitate future clinical applications.

Introduction

Sleep is one of the indispensable needs of human beings and is essential for maintaining physical and mental health(Moul et al., 2002). Insomnia is a sleep disorder characterized by frequent and persistent difficulties in falling asleep and/or maintaining sleep and leading to dissatisfaction with sleep(Practice, 2017). According to epidemiological studies, 45.4% of the respondents in China have experienced varying degrees of insomnia in the past month, and 10% to 15% of adults meet the diagnostic criteria for insomnia. The symptoms of nearly half of the patients with severe insomnia can last for more than 10 years(Practice, 2017; Sleep Disorder Group, 2012). A large number of studies have shown that insomnia seriously affects health and quality of life, and can cause a variety of problems, including memory problems, depression, irritability, cardiovascular and cerebrovascular diseases and so on(Baglioni et al., 2011; Janson et al., 2001; Roane and Taylor, 2008). Therefore, looking for effective ways to improve sleep quality has a positive effect on individual health and social health.

Drug therapy, psychotherapy, physiotherapy, and cognitive-behavioral therapy for insomnia (CBTI), are commonly used treatments for insomnia currently(Lee and Lee, 2006). However, as the number of insomnia patients increases rapidly, more feasible treatments are needed for insomnia. Recently, more and more studies have found that aromatherapy is one of the non-drug treatments to improve sleep quality. Aromatherapy has a long history in China, and it has been used to strengthen the body and treat diseases since ancient times. Aromatherapy works by inhaling, massaging, bathing and other ways to apply aromatic extracts to the human body. Compared with drug therapy, aromatherapy is more economical, simpler to use, and has fewer side effects. It is widely used in relieving stress, improving sleep disorders, and the treatment of depression, anxiety, etc. Nasiri Lari et al. found that inhaled lavender can improve sleep quality and quantity, quality of life and mood in diabetic patients suffering from insomnia. Lytle et al. conducted a randomized controlled trial of 50 patients with insomnia in an intermediate care unit and found that lavender aromatherapy may be an effective way to improve sleep (The score of the Richard Campbell Sleep Questionnaire was higher in the intervention group (48.25) than in the control group (40.10)).(Lytle et al., 2014; Nasiri et al., 2016; Nasiri Lari et al., 2020).

There are many clinical studies on the use of aromatherapy in the treatment of insomnia. The results show that aromatherapy has a significant effect on improving sleep quality in different populations through different ways, but different studies are different in application fields, types, duration, and so on, the quality of these studies is also uneven. At present, there is no systematic comprehensive analysis of randomized controlled trials (RCTs) investigating the efficacy of aromatherapy in the treatment of insomnia. Therefore, this paper conducts a meta-analysis of the therapeutic effect of aromatherapy on insomnia, in order to verify the therapeutic effect of aromatherapy on insomnia and to provide guidance for the clinical use of aromatherapy in the future.