Using an aromatherapy intervention with Citrus bergamia (bergamot) essential oil in adults in treatment for substance use disorder: A randomized controlled trial

Abstract

Objectives

This study had two aims. Aim one is to evaluate the feasibility and acceptability of using an aroma-based, self-managed intervention for adults in outpatient treatment for substance use disorder. Aim two is to examine the effects of a Citrus bergamia (Bergamot) essential oil intervention on the variables of comfort, ease, and stress.

Methods

A randomized controlled trial was conducted (NCT05660434). Adults in treatment for substance use disorder were randomized to either control group (standard care) (n = 55) or intervention group (standard care plus Citrus bergamia [Bergamot] essential oil intervention), three times a day for seven days (n = 45). All data were analyzed using an intention-to-treat method. Outcomes were measured using valid and reliable measures.

Results

One hundred participants were recruited over 11 months. Reasons for non or limited participation included feeling overwhelmed by the demands of treatment and everyday living. Data analysis showed psychological variable improvement with a significant increase in ease reported (P = 0.022) and DASS-21 subscales for depression (P = 0.007) and anxiety (P = 0.013) in the intervention group. Post-satisfaction survey results were positive, with overall enjoyment, perception of the aroma, and intention to continue to use the aroma inhaler post-trial, which was high.

Conclusions

Results from this study provide data to support the feasibility and acceptability of using essential oil via inhalation to help this population. Findings from this study will inform a more extensive study designed to examine effects within and between groups using a placebo.

What is known?

• •The literature shows that stress and anxiety are significant barriers to substance use disorder (SUD) recovery, often triggering relapse and complicating treatment. Effective stress management is crucial for supporting long-term recovery.
• •Bergamot Essential Oil (BEO) has shown potential in reducing anxiety and stress, with its chemical composition similar to Lavender, known for its calming effects.
• •Nurses and other healthcare providers can integrate aromatherapy into SUD treatment as a low-cost, non-pharmacological approach to enhance comfort, ease, and stress relief in patients, especially in underserved areas.

What is new?

• •The use of BEO via aroma inhalers in SUD treatment shows promise in improving comfort, ease, and stress reduction, offering nurses a feasible and low-cost intervention to enhance patient well-being.
• •Aroma inhalers provide nurses with a controlled, discreet, and convenient tool for supporting individuals in recovery from SUD, with positive participant feedback highlighting their potential for stress relief and ease of use.
• •Nurses, as key healthcare providers, can play a central role in integrating aromatherapy into SUD care. Still, future research with larger samples and objective measures is needed to refine this intervention and assess its long-term impact.

1. Introduction

Substance use disorders (SUD) represent a significant global health crisis, with over 35 million people affected worldwide. Yet, despite the high prevalence of SUD, only a fraction of those struggling receive adequate treatment [1]. The road to recovery is complex and often hindered by the multifaceted nature of the disorder, which is influenced by biological, environmental, and personal factors. Central to successful recovery is motivation for change, as individuals must confront not only the addictive behaviors but also the underlying emotional and psychological challenges associated with them. When an individual no longer has drugs in their system in sufficient quantities, a feeling of withdrawal and letdown occurs, often accompanied by a loss of pleasure in activities (anhedonia), an increased sensitivity to stress, and anxiety [2]. Traditional treatments, while effective, often leave patients and healthcare professionals seeking additional therapeutic approaches that can further enhance recovery progression [3].

Aromatherapy in the management of stress has been explored. In those undergoing hemodialysis, it appears that aromatherapy can be used as an inexpensive, fast acting, and effective treatment to reduce stress [4]. Reducing stress in ICU patients can support sleep and promote better outcomes [5]. Aromatherapy with massage and music significantly reduced anxiety and stress for emergency room nurses in one study [6]. However, insufficient evidence was found for the reduction of job-related stress in nurses using aromatherapy and massage [7]. Twenty-four-hour diffusion of lavender essential oil in a designated area on a nursing unit lowered reported stress levels in nurses [8]. Aromatherapy compared to music in a pediatric emergency waiting area showed a non-significant reduction in anxiety and stress on those days when aroma was diffused [9]. A forty to fifty percent decrease in stress, anxiety, feelings of fatigue, and feeling overwhelmed was found with the use of aromatherapy by aroma-patch in oncology nurses [10].

Research of Citrus bergamia (Bergamot) essential oil (BEO) shows promise. Effects on anxiety, corticosterone, and amino acid neurotransmitter levels, and behavior have been examined in rats [[11], [12], [13], [14]]. Linalool, an important constituent found in BEO, has been a focus of research in mice for anxiety, social interaction, and aggression [15,16]. Studies in humans with Lavandula angustifolia (Lavender) and BEO show potential for reducing anxiety and promoting overall well-being [10,[17], [18], [19], [20], [21]]. Bergamot has a high percentage of oxygenated terpenes, specifically linalool and linalyl acetate. In general, the main components, making up approximately 90 % of BEO, are limonene, linalyl acetate (29 %), linalool (9 %), β-pinene, and γ-terpinene [22,23]. Lavender and BEO share a similar chemistry in linalool and linalyl acetate. The decision to use BEO was primarily based on its chemical similarity to Lavender, as well as its relative unfamiliarity to the participants, which may help reduce any preconceived expectations of its effects.

The need for stress reduction in individuals undergoing SUD treatment is critical. Recovery is often fraught with emotional turmoil and external pressures, such as family demands, employment challenges, and the rigorous expectations of treatment programs [24]. For individuals in recovery, learning to cope with emotions without resorting to substance use is both a difficult and courageous journey [25]. As stress and anxiety can trigger relapse, finding effective ways to support stress management and enhance comfort during recovery is essential. This is especially relevant in rural areas like West Virginia, which is at the epicenter of the opioid crisis in the United States [26]. The region faces unique barriers to treatment, including geographic isolation, lack of transportation, and limited resources, which exacerbate the challenges of maintaining long-term recovery [27].

In this context, a comprehensive theoretical framework that includes comfort and ease as essential components of recovery was utilized to guide this study. The theory of comfort, as defined by Kolcaba [28], emphasizes the relief of suffering and the provision of comfort in the face of distress. The concept of “welcoming ease,” introduced by Reven [29], further extends this framework by focusing on the nurse-patient relationship as a catalyst for alleviating distress. Aromatherapy, as an adjunct to traditional care, aligns with these theoretical perspectives by offering a non-pharmacologic intervention that promotes relaxation and reduces psychological discomfort. Historical foundations of aromatics in nursing practice, dating back to Florence Nightingale’s emphasis on creating healing environments, support the integration of such therapies into modern clinical settings [30].

Building upon this theoretical basis, this study aims to explore the potential of BEO in reducing stress and enhancing comfort for individuals in outpatient SUD treatment programs in north central Appalachia, United States. The role of stress in SUD recovery is well-documented, with individuals often experiencing heightened anxiety, depression, and distress during the treatment process [31]. Aromatherapy, particularly using BEO, could offer a viable tool to mitigate these stress responses, providing a sense of calm and relief as individuals navigate the challenges of recovery. Studies have shown that essential oils can positively influence mood and reduce anxiety in various clinical settings, though their application in SUD treatment has yet to be thoroughly investigated [4,32]. This study seeks to fill this gap by examining the impact of BEO on comfort, ease, and stress in individuals undergoing treatment for SUD.

The purpose of this study is to present a simple-to-use, low-cost aromatherapy-focused intervention that may be used to address the stress and difficulty of treatment for SUD with the expected outcomes of being feasible and acceptable and providing greater comfort and ease and a reduction in stress. To do this, the following aims are addressed. Aim 1. Evaluate the feasibility and acceptability of a BEO intervention for adults in treatment for SUD with examined recruitment, fidelity, and cost. Aim 2. Test the effects of a BEO intervention on comfort, ease, and stress in adults in a SUD recovery program. Hypothesis 2a: The intervention group will report higher scores on comfort and ease. Hypothesis 2b: The intervention group will report lower scores in stress.

2. Methods

2.1. Study design and participants

A single-blinded randomized controlled pretest-posttest study was conducted at a large behavioral healthcare facility in northcentral West Virginia, USA (ClinicalTrials.gov: NCT05660434). The study followed Consolidated Standards of Reporting Trials (CONSORT) guidelines with two groups (Fig. 1), and randomization was performed using Microsoft Excel. Participants were assigned IDs and blinded to group allocation until consent was obtained.

Fig. 1.

The CONSORT flow diagram.

Participants were adults in a Comprehensive Opioid Addiction Treatment (COAT) program (n = 640) and in a medication assisted treatment (MAT) outpatient program in a free clinic in north central Appalachia (n = 15). Inclusion criteria: >18 years, SUD diagnosis, and willingness to participate. Exclusion criteria: asthma or other serious respiratory conditions, pregnancy, citrus aversion or allergy. Because of the multimodal nature of SUD treatment, patients undergoing other concurrent interventions or treatments for SUD were not excluded.

There is an identified lack of fully powered studies involving aromatherapy. Therefore, this study continued to meet the power analysis benchmark to determine statistical significance for secondary outcomes [[33], [34], [35], [36], [37]]. The sample size was calculated using G∗Power v.3.1.9.7 on repeated measure ANOVA given α = 0.05, moderate effect size (0.25), power of 80 %, two groups with two measurements, correlation among repeated measures (0.50), for a total sample size of 98 [38]. One hundred participants were recruited. All data were analyzed using an intention-to-treat method. Study details are summarized in the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT, Appendix A) checklist, with participant allocation shown in the CONSORT flow diagram (Fig. 1).

2.2. Randomization and blinding

The principal investigator (PI) and team collaborated with behavioral health therapists and administrators for recruitment. The PI attended online, and in-person group therapy sessions, and those who were interested shared their contact information. Randomization was done using Microsoft Excel and concealed until consent. A single-blind approach was used, with the PI blinded to allocation. Participants were not told their group assignment, and group allocation was revealed when they received their study packet. The biostatistician was not informed about group allocation.

2.3. Interventions

This intervention was created by the authors, who included a biostatistician, a licensed social worker, and researchers familiar with both quantitative and qualitative methodology. The PI was an Aromatherapist with advanced training and Registration in Aromatherapy in the United States. The study took place in the home or community-based setting of participants. Measures to ensure data accuracy included the use of the daily logbook (DLB) and text, phone, and email messages. Attrition and loss to follow up were also considered.

2.3.1. Rationale for a method of aromatic intervention

While there is limited data available showing how long or how much aromatherapy is enough to make an impact, there is evidence to show that it may be effective even when used for a short duration [[39], [40], [41], [42], [43], [44]]. The BEO was chosen for its chemical profile of major constituents that are reported to be relaxing and stress-reducing (Appendix B). The intervention group accepted the inhalation of BEO via an Aethereo®Stick (aroma inhaler) prepared by Plant Extracts Intl., USA and designed to deliver 0.83 $\mu$ L of EO with a “normal” inhalation. A single essential oil, BEO was chosen for its chemical profile of major constituents determined by gas chromatography/mass spectrometry (GC/MS). These include limonene (38.36 %), linalyl acetate (29.20 %), and linalool (11.70 %), all of which are reported to be relaxing and stress-reducing [12,45]. Similarity to Lavender was also considered, and it was reasoned that BEO would be less known than Lavender, therefore, less prone to bias from the expectation of its traditionally calming effects. The essential oil used in this study was obtained from species not classified as threatened according to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES-protected) report https://cites.org/eng/disc/what.php.

Many studies of aromatics included multiple administrations of essential oils either via inhalation or inhalation plus massage, including weekly full-body massage using essential oils for three weeks [43,44], weekly for four weeks [41,42], daily 20 min application for five days [39], and three times weekly for five weeks [40]. In the case of this study, a seven-day intervention was chosen after a small pilot, and it was determined that interest in the intervention was high for about seven days. The use of reminder texts, emails, and phone calls on days one through three was also determined to be helpful during this pilot.

2.3.2. Intervention and control group

Throughout this study, both groups received standard care, which included group and individual therapy, MAT, and continuous access to mental healthcare providers. Both groups received reminders about the study through calls, texts, and emails (Fig. 2).

Fig. 2.

Study progression.

The intervention group received standard care plus an aroma inhaler of BEO (Appendix B) that was used for three inhalations three times daily for seven days. The PI taught all participants via verbal instruction and demonstration to hold the aroma inhaler about 1–3 inches (2.2–7.62 cm) below the nose and inhale for 3 s, holding the breath for 3 s. Participants could adjust this timing to their preference. All study packets included information about the safe use of aromatherapy and essential oils. Baseline olfactory ability was assessed via self-report or aroma inhaler testing. Self-monitoring was done using the DLB.

If participants reported adverse reactions (e.g., headache or discomfort with the aroma), they were removed from the intervention. The PI ensured proper handling and storage of the aroma inhaler. Aroma inhalers were factory sealed and provided in tamper evident packaging. Materials Safety Data Sheets (MSDS) and GC/MS information were provided by Plant Extracts Intl. Safe handling and storage information was provided to all study participants and the behavioral healthcare team members.

The control group received standard care, a study folder, and instructions but no aroma inhaler. The control group tracked daily comfort using the DLB. The control study packet contained the DLB and post-surveys of comfort, ease, and stress, but there were no aroma-specific questions.

2.4. Measures

2.4.1. Prescreen survey

A prescreen survey designed by researchers assessed eligibility and supported reporting as per the Aromatic Research Quality Appraisal Taskforce (ARQAT) recommendations in the Transparent Reporting for Essential Oil and Aroma Therapeutic Studies (TREATS) checklist [46].

2.4.2. Daily logbook (DLB)

The DLB was created by the researchers and tracked intervention fidelity and comfort, reducing recall bias. The intervention group recorded aroma inhaler use and comfort levels, while the control group only tracked comfort. The DLB served as an attention control for the control group [47].

Kolcaba developed a 100 mm visual analogue scale (VAS) to use concurrently with the The Generalized Comfort Questionnaire (GCQ) [28]. The VAS was part of the DLB, all participants were asked to indicate their agreement with the statement “I feel as comfortable as possible today” from “strongly disagree” to “strongly agree” by marking an “x” on the line. The rating was measured in millimeters and given a number value between 0 and 100, with 0 indicating the least comfort and 100 indicating the most comfort.

2.4.3. Pre and post-intervention measures

2.4.3.1. Generalized Comfort Questionnaire

GCQ scale was designed by Kolcaba to assess comfort and has been used in a variety of settings. A common theme in the settings is that they are complex, very much like the outpatient treatment setting for SUD. Comfort means more than simply an absence of pain [28]. After pilot testing, a modified version of the GCQ was used. According to Kolcaba, many nurse researchers begin with the full 48 questions and reduce and modify the GCQ to fit the study population and purpose. When applying Comfort Theory to various populations, Kolcaba encourages researchers to modify the GCQ on their own, and permission was provided by the developer. The reduced scale of 28 questions had good internal consistency with a Cronbach’s alpha coefficient of 0.928 to 0.910. The 28-question scale contained an evenly distributed number of questions within the taxonomic structure of the GCQ including relief (8-questions), ease (10-questions), and transcendence (10-questions) in the physical, psychospiritual, environmental, and sociocultural contexts. The total items rated on the 6-point Likert scale ranged from “strongly disagree” (1-point) to “strongly agree” (6-points). The total score ranged from 28 to 168. A higher score indicated a greater perception of comfort. Because the Ease Measure [48] was also used, the subscale of ease in the GCQ was used to assess concurrent validity.

2.4.3.2. Ease Measure

Adenmosun et al. (2021) developed the Ease Measure to quantify ease positively, citing that previous measures often claimed that ease was present when stress levels were lowered, but this negative assumption may not always be valid [48]. The Ease Measure had 20 questions rated on a 4-point Likert scale ranging from “never” (1-point) to “always” (4-points). The total score ranged from 20 to 80. A higher score indicated greater ease. The Ease Measure is a reliable and valid instrument for measuring ease in adults, with a Cronbach’s alpha coefficient of 0.86. For this study, the Cronbach’s alpha coefficient was between 0.863 and 0.881. Developers provided permission to use the Ease Measure.

2.4.3.3. Depression, Anxiety, and Stress Scale (DASS-21)

Lovibond and Lovibond (2011) developed the 42-item DASS to measure the negative emotional states of depression, anxiety, and stress [49]. Since then, the DASS-21 has been created and chosen for use in this study. The 21 questions were rated on a Likert scale ranging from 0, “did not apply to me at all,” to 3, “applied to me very much or most of the time.” A total score ranged from 0 to 63. A higher score indicates greater perceived depression, anxiety, and stress [49]. Subscales of depression and anxiety were left in the instrument to describe the sample and identify co-occurring confounding variables. The DASS-21 is a valid and reliable instrument with a Cronbach’s alpha coefficient of 0.88 (subscales of depression, anxiety, and stress, each with seven items, ranging from 0.82 to 0.93) and for this study, 0.920 to 0.929. Permission to use the DASS-21 was provided by the developers.

2.4.3.4. Post-aroma Questionnaire and qualitative data

A researcher constructed post-survey with three Likert-scale (0-10) questions allowed participants in the intervention group to rate their overall enjoyment of the aroma, the usual strength of the aroma, and how likely they were to continue to use the aroma inhaler after the study. Perceived enjoyment of the aroma inhaler was assessed using the question, “On a scale of 0–10, rate overall how enjoyable the aroma of the inhaler was.” With 0 being “not enjoyable at all” and 10 being “very enjoyable”. Perceived intensity of the aroma inhaler was assessed post-study with the question, “On a scale of 0–10, rate the usual strength of the smell of the aroma inhaler,” with 0 beings “no strength” and 10 being “the strongest it could be.” To see how likely those in the study thought they would be to continue using their aroma inhaler after the study ended, the question “How likely are you to continue to use this aroma inhaler” with 0 beings “not likely at all” to 10 being “very likely”. The measure had a Cronbach’s alpha coefficient of 0.622. Qualitative data on daily comfort were collected using comments from participants entered into the DLB and post-aroma questions.

2.5. Data collection

Training of staff and designees about intervention delivery was a key element to ensure the quality of the intervention [50]. The PI oversaw recruitment, consent, and intervention delivery. The PI monitored compliance monthly and as needed. Upon IRB approval, the PI introduced the study to staff and participants, ensuring informed consent. Participants were assured that they could withdraw at any time without repercussions.

Data were collected both online and in person. To begin, participants were introduced to the PI during therapy sessions, and contact details were provided if they were interested. Consent was obtained either online or in person, and eligibility was determined through prescreening. All participants completed pre-surveys and received instructions on DLB. After seven days, all participants completed post-surveys and returned the DLB. All participants received a $20 gift card, and the aroma inhaler was given to the control group.

2.6. Ethical considerations

This study was approved by the WVU Institutional Review Board in July 29, 2022 (2204562633) and followed the Declaration of Helsinki. All participants had informed consent. The PI ensured data were managed and handled appropriately (de-identified and access limited to authorized parties) and that appropriate steps were taken for data cleansing and dissemination of results.

2.7. Statistical analysis

Data were analyzed using SPSS version 28. Descriptive statistics were used to analyze the baseline demographic data. The values for Skewness and Kurtosis between −2 and +2 are considered acceptable in order to prove normal distribution in continuous outcomes [51]. Correlation analysis was done using both Pearson and Spearman tests. Group differences at baseline for study variables were determined using an independent samples t-Test. A paired sample t-test was used to compare continuous measures, including subscales between baseline (time 1) and post-intervention stage (time 2). Chi-square was used to examine the associations between two categorical variables. An intention-to-treat approach including all available data was applied, and statistical significance was set at α = 0.05. Data were stored securely using Qualtrics and REDCap systems (see Appendix A).

3. Results

3.1. Baseline characteristics

A total of 100 participants were randomized, with 38 completing all study materials and three completing no study materials (two in the intervention group and one in the control group, respectively) (Fig. 1). Of the participants, 39 were male and 61 were female. The majority were white, non-Hispanic (n = 96). Ages ranged from 19 years to greater than 60 years, with the majority being between 31 and 40 years of age (n = 49). The most frequent primary diagnosis was opioid use disorder (OUD) (n = 75) followed by multi SUD (n = 22). Baseline characteristics in this trial are shown in Appendix C. Slightly more participants in the intervention group had tried or thought they knew what BEO was, 15 (33.3 %) compared with 10 (18.2 %) in the control group. Previous use of integrative modalities was 23 (51.1 %) in the intervention group and 35 (63.6 %) in the control group. Based on prescreening data, there was little bias toward BEO.

3.2. Primary outcomes

Aim 1. Evaluate the feasibility and acceptability of a BEO intervention for adults in treatment for SUD with examined recruitment, fidelity, and cost.

Feasibility and acceptability were analyzed. Overall, it was feasible to enroll, recruit, and retain participants over 11 months. The estimated population between 2022 and 2024 was 645, with 180 (29 %) interested and 130 (72 %) prescreened. One hundred participants were recruited from Sep. 2022 – Jan. 2023 to Oct. 2023–March 2024 (11 months) (Fig. 1).

Cost analysis and reasons for attrition were recorded. The cost was $30–35 USD per participant, including the cost of mailing and gift cards. Aroma inhaler prices, on average, range between $5 to 7 USD and are potentially affordable to many adults. Reasons for attrition included lack of time, demands of everyday living, and family stress. There were no reports of participants’ dislike of the intervention.

Qualitative data were gathered using the DLB and the post aroma questions. Comments in the DLB and post aroma questionnaire show the intervention as acceptable and helpful, including as examples, “Feeling calm while using the inhaler”, “I really enjoy the aroma, I felt relaxed a lot of times when I used it … ”, “Continues to help relax/ground me when stressed”, and “I used an additional time at around 9:30 p.m. I feel that it helps me to calm down before bed”. The behavioral healthcare team was supportive of the intervention, and comments were positive.

3.3. Secondary outcomes

Aim 2. Test the effect of a BEO intervention on comfort, ease, and stress in adults in a SUD recovery program. Hypothesis 2a: The intervention group will report higher scores on comfort and ease. Hypothesis 2b: The intervention group will report lower scores in stress.

The Skewness and Kurtosis values for outcome variables (comfort, ease, and stress) in both intervention and control groups were within (−2, 2), which indicates that these variables follow a normal distribution. A comparison of GCQ scores, Ease Measure scores, and DASS-21 scores between the two groups is shown in Table 1, Table 2, Table 3. Independent t-test showed significant differences between intervention and control groups post intervention in subset Ease of GCQ (t = −2.61, P = 0.010), and DASS-21 subscale Depression (t = 2.13, P = 0.035), Anxiety (t = 2.52, P = 0.013), and Stress (t = 2.91, P = 0.004). However, no difference between the two groups was found post-intervention in the overall GCQ (t = −0.72, P = 0.473) and GCQ subscales Relief and Transcendence (t = −0.66, P = 0.513 and t = −1.21, P = 0.288, respectively). No significant difference was found between the two groups in the Ease Measure (t = −0.99, P = 0.323) or the overall DASS-21 (t = 1.30, P = 0.196). The data did not support hypothesis 2a of increased comfort scores overall (t = −0.476, P = 0.318). Analysis of the GCQ subscale Ease, did show a statistically significant difference in the intervention group between pre and post intervention (t = 2.12, P = 0.043). No significant difference was seen in subscales of the GCQ for Relief and Transcendence (t = −1.14, P = 0.260 and t = −1.21, P = 0.233 respectively) (Table 1).

Table 1.

Comparison of Generalized Comfort Questionnaire (GCQ) scores between the two groups before and after the intervention.

Variables	Pre-intervention, Mean (SD)	Post-intervention, Mean (SD)	t	P
Relief
Intervention group (n = 45)	31.58 (6.81)	32.91 (8.23)	-1.14	0.260
Control group (n = 55)	32.13 (6.65)	31.80 (8.41)	0.28	0.780
t	0.41	-0.66
P	0.686	0.513
Ease
Intervention group (n = 45)	39.22 (8.25)	44.28 (8.32)	2.12	0.043
Control group (n = 55)	40.54 (8.71)	39.30 (7.60)	1.04	0.304
t	0.77	-2.61
P	0.441	0.010
Transcendence
Intervention group (n = 45)	42.60 (7.49)	43.86 (6.82)	-1.21	0.233
Control group (n = 55)	43.86 (8.04)	42.13 (7.28)	1.67	0.101
t	0.80	-1.21
P	0.424	0.228
Overall
Intervention group (n = 45)	116.29 (21.80)	117.91 (20.60)	-0.476	0.318
Control group (n = 55)	114.17 (22.05)	114.84 (21.68)	-0.241	0.810
t	-0.48	-0.72
P	0.631	0.473

Table 2.

Comparison of Ease Measure scores between the two groups.

Group	Pre intervention, Mean (SD)	Post intervention, Mean (SD)	t	P
Intervention group (n = 45)	53.04 (9.93)	57.21 (8.05)	−2.38	0.022
Control group (n = 55)	53.88 (8.99)	55.58 (8.21)	−1.74	0.088
t	0.44	−0.99
P	0.659	0.323

Table 3.

Comparison of Depression, Anxiety, and Stress Scale (DASS-21) scores between the two groups.

Variables	Pre-intervention, Mean (SD)	Post-intervention, Mean (SD)	t	P
Depression
Intervention group (n = 45)	6.62 (4.87)	4.87 (3.74)	2.82	0.007
Control group (n = 55)	5.97 (4.01)	6.73 (4.75)	-1.27	0.210
t	-0.74	2.13
P	0.463	0.035
Anxiety
Intervention group (n = 45)	5.98 (4.22)	4.48 (2.89)	2.58	0.013
Control group (n = 55)	5.52 (3.54)	6.16 (3.64)	-1.33	0.191
t	-0.59	2.52
P	0.559	0.013
Stress
Intervention group (n = 45)	8.18 (4.08)	7.44 (3.89)	1.14	0.260
Control group (n = 55)	8.55 (4.20)	9.89 (4.44)	-2.17	0.009
t	0.45	2.91
P	0.654	0.004
Overall
Intervention group (n = 45)	20.49 (11.48)	18.54 (10.40)	1.15	0.128
Control group (n = 55)	20.28 (10.75)	21.34 (10.95)	-0.79	0.432
t	-0.09	1.30
P	0.925	0.196

For hypothesis 2a, a statistically significant difference was seen in the Ease Measure in the intervention group between pre and post intervention (t = −2.38, P = 0.022) with the subscale Ease from the GCQ correlating these results. Comments from the DLB, as mentioned above, also supported the correlation of increased ease. For hypothesis 2b, no statistically significant difference was seen in the overall DASS-21 scores in the intervention group between pre and post intervention (t = 1.15, P = 0.128). Subscales of the DASS-21 showed statistically significant decreases in depression and anxiety (t = 2.82, P = 0.007 and t = 2.58, P = 0.013, respectively). There was a positive correlation between the VAS and GCQ score (r = 0.683, P < 0.001). There was a positive correlation in the intervention group between the Ease Measure and the Ease subscale of the GCQ, pre (r = 0.356, P < 0.001) and post (r = 0.295, P < 0.003) intervention.

Eighty-one percent (34 of 45) in the intervention group completed the DLB. The majority (98 %) used the aroma inhaler at least 3 times daily as directed. During days 4 through 7, many used the aroma inhalers four times daily.

Post aroma questionnaire satisfaction survey results were positive and showed that overall enjoyment, perception of the aroma, and intention to continue to use the aroma inhaler post-trial were high. There were no reports of urgent psychological or clinical care being needed. There were no reports of adverse reactions in this aromatherapy intervention.

4. Discussion

The findings of this randomized controlled trial contribute valuable insights into the feasibility and acceptability of using an aroma inhaler with BEO as an intervention for adults undergoing treatment for SUD. The results demonstrate that the intervention was both feasible and acceptable, with a statistically significant improvement observed in the intervention groups’ reported ease compared to those receiving standard care. The positive trends in comfort, ease, and stress reduction further suggest that incorporating this type of complementary therapy into SUD treatment programs may be beneficial. This is particularly noteworthy as there is limited research on the use of aromatherapy in this context, with no prior studies directly exploring the use of BEO or aroma inhalers in adults in SUD recovery.

The current study’s results align with previous research on the anxiolytic properties of BEO, particularly its potential to reduce stress. Research has shown that BEO can bind to GABA receptors and influence the hypothalamic-pituitary-adrenal (HPA) axis, both of which may explain its calming effects [11,14]. The improvement in ease reported by participants in this study mirrors findings from other aromatherapy research, such as the work by Tang and Tse (2014), which demonstrated the mood-lifting effects of pleasant odors on community-dwelling older adults [52]. In addition, while the DASS-21 did not yield significant results in the intervention group, it is important to note that the scores trended positively, suggesting that larger studies with more robust sample sizes may reveal stronger effects. Additionally, subscales of the DASS for depression and anxiety showed statistically significant improvement in these measures in the intervention group when compared to the control group. Future research could explore this finding by looking closer at depression and anxiety in relation to SUD treatment.

One of the key strengths of this study was its focus on the use of an aroma inhaler, which allows for a precise level of control over the delivery and dosage of the essential oil. This method has significant advantages over other aromatherapy delivery systems, such as diffusers, which can be difficult to control in terms of both dose and spread. For example, several studies incorporated methods of inhalation and diffusion of aromas, including via an electric potpourri diffuser [53], aroma stone [54], surgical mask [55], and essential oil evaporating from a glass bowl [56]. Each of these methods seemed fairly cost-effective. However, delivery would be difficult to calculate and control. The use of an aroma inhaler allowed more control of dose and delivery than these other inhalation methods.

The inhaler method also offers a level of privacy and convenience that may increase adherence, particularly in remote or economically disadvantaged areas like Appalachia. Participants in the study reported that they found the aroma inhaler easy to use and that it provided them with a sense of relief when used as needed throughout the day. These findings suggest that aroma inhalers could be a promising tool for managing stress and enhancing comfort in individuals in recovery from SUD.

Despite the promising results, there were several limitations in this study that should be considered when interpreting the findings. One major limitation was the small sample size, particularly in the intervention group, where only 18 participants completed all study measures. This limited the ability to detect statistically significant differences in secondary outcomes, such as comfort and stress. Additionally, the reliance on self-report measures for comfort, ease, and stress could introduce biases, as participants may have been influenced by their expectations or desire to report positive outcomes. Future studies could benefit from incorporating objective biomarkers, such as salivary cortisol levels, to provide a more comprehensive assessment of stress reduction.

The study also lacked follow-up data beyond one week after the intervention, making it difficult to determine whether the benefits in ease and stress reduction were sustained over time. Given the dynamic nature of SUD recovery, where stress levels may fluctuate due to various life circumstances, it would be valuable to assess whether the aroma inhaler remains effective in the long term. Longitudinal studies with extended follow-up periods would help clarify whether the intervention has lasting effects and if it could become a sustained part of participants’ recovery routines.

In terms of practical implications, this study suggests that incorporating aroma inhalers into SUD treatment programs may provide an accessible, cost-effective, and non-invasive method for reducing stress and enhancing comfort. Nurses and other healthcare providers working with individuals in recovery from SUD could consider using this intervention in both inpatient and outpatient settings. Given the simplicity of the aroma inhaler, it is particularly well-suited for use in community-based programs, where participants may benefit from having a portable, discreet tool for managing stress and anxiety on the go. Furthermore, the positive feedback regarding the inhaler’s ease of use and its potential for stress relief in participants underscores the feasibility of integrating such interventions into routine care for SUD recovery.

Looking ahead, future research should focus on expanding the sample size and including a more diverse population of individuals in SUD recovery. While this study was conducted in north central Appalachia, it will be important to explore the acceptability and efficacy of the aroma inhaler in other geographic regions and populations. Additionally, further research could examine the potential benefits of combining aromatherapy with other therapeutic interventions, such as cognitive behavioral therapy or mindfulness-based practices, to enhance overall treatment outcomes. Future studies could also explore the neurobiological mechanisms underlying the effects of BEO and other essential oils on stress and anxiety in individuals with SUD.

Finally, as the field of aromatherapy continues to evolve, it will be important to build on the growing body of evidence supporting its use in managing stress and enhancing comfort. Nurses, as key figures in healthcare delivery, are uniquely positioned to incorporate complementary therapies like aromatherapy into their practice. By continuing to explore and evaluate such interventions, we can provide individuals in SUD recovery with additional tools to support their journey toward healing, health, and wellness.

5. Conclusions

Using BEO via an aroma inhaler three times daily and as desired for one week in adults undergoing treatment for SUD in a community setting has proven to be a feasible and acceptable intervention that leads to increased comfort, ease, and stress reduction. Nurses, in collaboration with the care team, can utilize this simple, low-cost intervention to enhance comfort and support patient well-being. Although the sample was representative of adults in outpatient treatment in north central Appalachia, the findings are not generalizable to other populations. While most participants completed the study, challenges with obtaining post-surveys highlighted the need for improved data collection strategies. Future research should expand to include a wider population, incorporate objective measures to correlate subjective data, utilize enhanced electronic data collection methods, and extend follow-up periods to assess the long-term effects. Further studies are needed to determine the optimal dosage and refine the intervention. This study adds valuable insights to the growing body of knowledge on aromatherapy-focused interventions in healthcare, particularly in the context of SUD treatment.

CRediT authorship contribution statement

Marian Elaine Reven: Conceptualization, Methodology, Validation, Formal Analysis, Investigation, Data curation, Writing – original draft, Writing – review & editing, Supervision, Project administration, and Funding acquisition. Roger Carpenter: Conceptualization, Methodology, Writing – original draft, Writing – review & editing, and Funding acquistion. Mary Jane Smith: Conceptualization, Methodology, Writing – review & editing. Amanda Newhouse: Methodology, Resources, Writing – review & editing. Kesheng Wang: Methodology, Data curation, and Writing – review & editing.

Data availability statement

The datasets generated and/or analyzed during the current study are available from the corresponding author upon reasonable request.

Funding

This research is funded through the West Virginia Nurses Association, Rosenthal-Riter Scholarship fund and through the West Virginia University School of Nursing Ruth and Robert Kuhn Nursing Research Foundation. Funding sources have had no role in the design of the study and data collection, analysis, and interpretation nor in the writing of the manuscript.

Declaration of competing interest

The authors have declared no conflict of interest.

Appendices. Supplementary data

The following are the Supplementary data to this article.