Non-participation Rate and Recruitment Barriers in Offering Yoga Intervention for Depression: A Scoping Review

Abstract

Background

Depression is a common mental health condition that globally affects legions of people, though interventions such as yoga have emerged as a complementary treatment for treating it. Despite its potential therapeutic benefits, recruitment and retention in yoga-based interventions still remain a challenge, resulting in limiting their use in clinical settings.

Summary

This scoping review aimed to identify and categorise the barriers contributing to non-participation and recruitment challenges in implementing yoga-based interventions for depression. Major databases such as PubMed, Embase, and Scopus were used for identifying the studies reporting on recruitment challenges in yoga interventions for depression.

Original studies

(a) in which yoga served as the primary intervention, that measure any health outcomes, (b) which studied adults aged ≥18 years with mild/moderate depressive condition, and (c) RCT studies published in English were included. Of the 445 studies screened, only five met the eligibility criteria. Across studies, the yoga intervention varied in type, duration, method of delivery, and several key barriers like stigma about mental health, limited awareness of therapeutic benefits of yoga, cultural perceptions, and physical limitations that hindered the rate of participation were identified.

Key Messages

Addressing the recruitment barriers is essential to enhance the utilisation of complementary treatments like yoga for treating depression. Strategies like culturally sensitive community outreach with a flexible mode of delivery are required, and awareness of alternate treatment approaches like yoga with its potential benefits should be created to improve the participation rate. The review provides a foundation for designing inclusive and easily accessible yoga-based mental health programmes for treating depression and related conditions.

Introduction

Depression is a common mental health condition that poses persistent sadness, despair, and displeasure in day-to-day activities, globally affecting legions of people. Developing holistically effective interventions is essential to empower depressed individuals towards recovery. Conventional treatments, like pharmacotherapy and psychotherapy, are effective but they often pose certain limitations such as side effects, high costs, and limited accessibility, which has led to an increased interest in discovering complementary and alternative therapies, like yoga, as potential alternative interventions for managing depression.^{1, 2}

Some studies reported the role of yoga in reducing the severity of depressive symptoms, when compared to other mind-body practices. Integrating holistic complementary therapy like yoga helps in reducing the symptoms of depression by enhancing the overall quality of life towards recovery. ³ However, the effectiveness of yoga in treating depression remains an active area of investigation, either as a standalone or adjunctive treatment for mild and moderate depression. ⁴

Despite the shreds of promising evidences, the challenges in recruitment and the rate of non-participation in offering yoga interventions have significant barriers in practically implementing yoga as intervention in clinical trials. ⁵ For instance, a study on tele-yoga interventions reported that a significant ratio of eligible participants avoided to participate due to certain factors like lack of time or energy, hesitation or lack of knowledge towards yoga and the digital delivery of the intervention. ⁵

Previous studies explore the benefits of yoga in treating depression, with inclusive research on recruitment challenges and the rates of non-participation in interventions which remains limited. Therefore, addressing these challenges is vital for developing effective strategies for recruitment to ensure adequate sample sizes, and for essentially improving health outcomes. ⁶ With actionable insights, our review enhances the practicability in offering effective yoga-based treatments for mild and moderate depression, and to identify the challenges in implementing yoga for treating depression and strategically addressing the following research questions:

• What are the strategies to address challenges in recruitment and participation in yoga interventions for depressive patients?

• How are yoga interventions reported to be effective in treating mild and moderate depressive patients?

Methodology

This is a registered scoping review at the OSF Registries, aligning under the PRISMA – Scoping Review Checklist as enclosed in the Supplementary Material 1. ⁷

Eligibility Criteria and Selection of Sources of Evidence

Inclusion Criteria:

1. Population: Adults aged ≥18 years, diagnosed with mild/moderate depressive condition using any standardised assessment tools that align with the diagnostic criteria of ICD-10 or DSM-IV/DSM-V were included.^{8, 9}

2. Intervention: Studies in which yoga served as the primary intervention, providing at least one structured yoga session to participants, that measure any outcomes. It could be any type of yoga as an intervention.

3. Comparator: Comparator was not required due to the exploratory nature of the scoping review.

4. Outcome: Studies assessing at least one measurable outcome related to changes in the severity level of depression, the overall well-being of the participants and findings focusing on non-participation rate and barriers in offering the intervention.

5. Design: To ensure a high level of research rigour and minimise bias, only RCTs published in English were included to maintain consistency in data interpretation.

Exclusion Criteria:

1. Studies including individuals with severe depression or other mental illnesses other than mild and moderate depression were excluded.

2. Studies that lacked yoga as the primary intervention were excluded.

3. Non-RCT studies were excluded as they lacked the random allocation of participants. Non-original research, such as review articles, meta-analyses, systematic reviews, and animal studies, was excluded.

These criteria were established to ensure that the review focuses on information captured from high-quality, methodologically robust RCTs that evaluated yoga as an intervention for depression.

Information and Strategies of Search

The systematic search was completed on 4 March 2025 by using PubMed, Embase, and Scopus with the search terms related to the PICO criteria. The detailed search strategy of the articles is enclosed in Supplementary Material 2.

The findings were imported into Covidence for rigorous evaluation, and duplicates were removed. ¹⁰ In Phase I, two authors (AS and SA) conducted independent screenings of the titles and abstracts, whereas Phase II involved an accurate evaluation of full texts according to the eligibility criteria of the study (Figure 1). Any disagreements between the authors (AS and SA) were resolved with consensus or by the corresponding author (SJK), ensuring consistent decisions from screening the title and abstract to full-text review. The details of excluded articles with reasons and reference list are provided in Supplementary Material 3.

Figure 1. Non-participation Rate and Recruitment Challenges in Yoga Interventions for Depression.

Extraction of Data

Two independent authors (AS and SA) extracted the data from the included articles for systematic review. Any disagreements between the authors (AS and SA) regarding the data were solved through consensus or by the senior subject expert (SJK). The extraction of the data includes details about the author, year of publication, design of the study, patient information (e.g., age, gender, and diagnosis), sample size and groups, study settings, instruments used for major depressive disorder (MDD) diagnosis, intervention details such as the type of yoga, its frequency, duration, results and outcomes of the study as represented in Table 1. Other outcome measures other than depression were excluded as they fall outside the objectives of this scoping review.

Table 1. Descriptive Characteristics of Included Studies (N = 5).

Author Name with Year	Design, Sample Sizes (N, YG and CG)	Study Settings, Intervention (Duration/frequency/study Setting) and Control	Instruments Used	Study Outcomes	Reasons for Non-participation and Recruitment Barriers
Nadholta (2023) 11	RCT (N = 77/100 completed; I = 34, CG = 43)	The YG participated in a 16-week (online) session, whereas the CG underwent TAU at PGIMER in Chandigarh, India.	DASS-42	Depression tends to increase as pregnancy progresses, but prenatal yoga helps in managing and improving the QOL of the mothers.	Blinding was unfeasible, biasing results. A 20% attrition rate was linked to low yoga awareness. Self-reports affected validity. Motivation and social desirability impacted adherence. Online interventions faced connectivity challenges.
Sangeetha Laxmi (2023) 12	RCT (N = 60; I = 30, CG = 30)	The YG practised rhythmic abdominal breathing and guided relaxation for 90 days, whereas the CG was under TAU.	BDI	In the yoga group, BDI scores dropped from 39.07 to 9.2, demonstrating the profound benefits of the add-on yoga therapy module.	Extending treatment duration and incorporating midpoint assessments may aid in restoring normal health.
Nugent (2021) 13	RCT (N = 122; 1:1 ratio)	YG had classes with breathing exercises, seated meditation, wrap-up and discussion of home practices at a private psychiatric hospital with two sessions per week for 10 weeks, whereas the CG underwent HLW classes, for every 10 weeks.	Quantikine high sensitivity ELISA immunoassays	IL-6 levels decreased over time in depressed patients persistently compared to those in the control group.	Further research is recommended to substantiate yoga’s benefits in pro-inflammatory processes.
Ravindran (2021) 14	RCT (N = 72; I = 53, CG = 19)	The intervention emphasised cyclical breathing and breath control (pranayama), including Ujjayi and Kapala Bhati techniques, which incorporated postures and guided meditation, allowing flexibility for varying ability levels of the participants, conducted in a hospital for eight weeks. The CG underwent psychoeducation.	MADRS	A decline in the symptoms of depression was observed.	Mild adverse events, such as shortness of breath, sweating, hot flushing, and effects from cyclic breathing, were reported.
Javnbakt, (2009) 15	RCT (N = 65; I = 34, CG = 31)	YG underwent Ashtanga Yoga in a yoga clinic for a period of 2 months, twice, 90 minutes of class, whereas the CG was under TAU.	BDI	The depressive scores in the experimental group decreased after yoga.	Generalization challenges were due to factors like gender-based population, intervention time period, and sample size.

Note: YG = Yoga group, CG = Control group, HAM D = Hamilton rating scale for depression, MADRS = Montgomery–Asberg depression rating Scale, BDI= Beck depression inventory scale, PHQ = Patient health questionnaire, HLW = Healthy living workshop.

Results

Data extraction was carried out using a Microsoft Excel spreadsheet, where key characteristics from included studies were recorded. The extracted information is summarised in Table 1, which presents the descriptive findings of the included studies.

Overview of Included Studies and the Sources of Evidence

The scoping review was conducted in accordance with the PRISMA extension for scoping reviews (PRISMA-ScR). The primary search was conducted from databases such as PubMed, Scopus and Embase, identifying n = 445 articles. Of these, n = 68 were from PubMed, n = 328 from Scopus and n = 49 from Embase; and n = 72 duplicates were removed for further review. Of these, the remaining 373 studies were screened for review, of which n = 362 studies were excluded as they did not match the inclusion criteria. The remaining studies were retrieved and assessed based on eligibility (n = 11); among them, five studies were excluded due to wrong study designs (n = 5) and wrong patient population (n =1). Overall, a total of five studies were included for further review of the search and selection process, which is clearly charted as a flow chart in Figure 1.

As shown in Table 1 the description and characteristics of the included studies (N = 5), such as the author’s name with published year, design of the study, details of study settings, sample sizes (total sample size, sample sizes in intervention and control groups), details of the interventions (frequency/duration of each session), control group details, tools used for diagnosis of depression and findings on the intended outcomes measured from these studies related to non-participation rate and recruitment barriers in offering yoga interventions for depression.

To summarise, studies included demonstrated consistent therapeutic benefits of yoga for individuals with depression. Identified issues for non-participation included difficulties in attending regular in-person sessions, low awareness or motivation to engage in yoga intervention, technological challenges affecting online sessions, reduced engagement in virtual formats due to lack of direct supervision and environmental distractions.

Discussion

Overall, the results highlight considerable variation in the non-participation rates and recruitment challenges reported across the included studies. In general, yoga-based intervention studies face various barriers that impact the applicability and outcomes globally. Interpreting the findings of the review within the wider literature highlights the importance of these barriers and further opens opportunities for developing tailored yoga-based interventions that can help improve mental health outcomes.

A theme that recurred across the studies was that active engagement was required for yoga sessions, which may cause assessment bias; as blinding neither the participants nor the researcher is not practical in interventions like yoga. ¹¹ This may be due to depressive symptoms like fatigue or reduced motivation, which hinder compliance with interventions. Another important observation was the limited awareness of the perceived therapeutic benefits of yoga. This further contributed to dropouts and refusals to adhere to treatment. Hence, ensuring a safe, gentle and progressively structured yoga session can enhance the participant’s comfort and help in treatment retention.

However, as the treatment adherence is largely a measure of self-report, it can reduce the response bias due to social desirability, which can affect the validity of the study findings.

Participant motivation and social pressure can also affect compliance and adherence, while online delivery of the intervention faces challenges like network/connectivity issues and the audiovisual quality of the session. ¹¹ Evidence also suggests that extending the duration/frequency of the intervention and incorporating the midpoint assessments helps in improving the efficacy of the intervention. ¹²

Further exploration of the impact of yoga on the pro-inflammatory parameters is highly essential to understand its underlying physiological mechanisms. ¹³ Other adverse events, like mild shortness of breath/ discomfort from cyclic breathing, have also been reported in some interventions. ¹⁴ However, generalisation of these review findings is limited by gender-specific samples, differences in the style of the intervention, variations in its frequency and duration, as well as small sample sizes. ¹⁵

A recent study reported that the limited access to in-person sessions seems to result in discouraged participation in some studies, emphasising the need for more accessible delivery formats. ¹⁶ These findings parallel the challenges reported from research on complementary therapies, where the engagement is significantly influenced by cultural relevance and limited accessibility. ¹⁷

Collectively, the findings suggest the need for robust and participant-centred research designs to address the current gaps. Flexible scheduling of sessions, easy accessibility, culture adaptability, and community-based delivery programmes may help to bridge these barriers in recruitment and reduce the non-participation rate, thereby optimising the therapeutic potential of yoga interventions for depression.

Implications for Future Research

Researchers planning to offer yoga-based interventions should focus on improving the methodology to address the current gaps, to enhance the impact and practicability of the intervention.

Most importantly, developing standardised protocols for ensuring consistency across the studies is important, and focusing on long-term/midpoint evaluations help gain deeper insights to measure the sustained effectiveness of interventions like yoga. Personalising effective interventions tailored for specific populations or cultures helps in integrating complementary therapies like yoga in clinical practices. Challenges in accessibility and digital delivery of intervention should be addressed accordingly to improve the reach and engagement of yoga.

The socioeconomic factors can be considered through cost-effective analysis to globally integrate yoga as a therapeutic option in healthcare. In practice, these implications can offer opportunities in revising the research and enhancing the application of yoga as a scientific and valid healthcare treatment.

Limitations of the Review

There are several limitations across the included studies which impact inclusiveness and practicability. It is important to note that the review includes only RCT studies published in English and excludes other relevant non-English studies. The variations in styles, frequency and durations makes it challenging to compare findings for strong conclusions due to the heterogeneity observed in these yoga-based interventions. Notably, many studies lack proper methodologies, which fail in providing detailed protocols of the intervention followed, details of the instructor, delivery mode, and adherence to home practices.

Conclusion

Yoga interventions show promising evidence in reducing depressive symptoms and improving the overall quality of life among mild to moderate depressive individuals. Despite this, recent research reveals some notable findings in offering yoga, which include methodological limitations, barriers in participant engagement, and concerns of accessibility, which strongly suggest the requirement for more vigorous study designs, valid and standardised protocol, inclusively tailored for diverse populations across countries. Upcoming studies planning to offer yoga-based interventions should focus on evaluating the long-term impacts that incorporate mid-intervention-term assessments and mitigate biases in self-reported outcomes. Additionally, it is important to focus on raising awareness about the therapeutic potential of yoga and helping to overcome the obstacles faced in the online delivery of interventions and ensuring the safety of the participants, to expand the reach and commitment of participants towards the intervention. In practice, bridging these gaps will help us to develop a robust, evidence-based practice of yoga programmes as a scientifically valid and globally accessible complementary intervention within the system of mental healthcare.

Authors’ Contribution

We, the undersigned authors, confirm that our manuscript titled “Non-participation Rate and Recruitment Barriers in Offering Yoga Intervention for Depression: A Scoping Review” (https://doi.org/10.17605/OSF.IO/E46XB), is our original scientific work.

All authors have made substantial contributions to the manuscript and meet the authorship criteria as outlined by the journal’s guidelines.

Statement of Ethics

Not applicable. This study is a scoping review based on previously published data.

Declaration Statement

We hereby declare that the manuscript titled “Non-participation Rate and Recruitment Barriers in Offering Yoga Intervention for Depression: A Scoping Review” is original. It has neither been published elsewhere, nor is under consideration by any other journal. We assure that our study is authentic, accurate and no copyrighted material has been included without appropriate citation or permission. All the authors in the study have contributed substantially, reviewed the final manuscript, and approved its submission to the journal for publication. All ethical standards were adhered to and the required approvals were obtained. We assure that all relevant disclosures have been made and there are no conflicts of interest to declare.

Consent to Participate/publish

Not applicable.

Data Availability

The study protocol is registered and is publicly accessible under the OSF Registries, with all the supplementary materials, such as the PRISMA checklist for scoping reviews, the search strategies, and the lists of excluded studies with valid reasons for their exclusion, along with their reference list.

All data generated or analysed during this study are included in the manuscript and its supplementary files.