Abstract
Introduction: Substance use disorders (SUDs) are complex interactions between various genetic, environmental, developmental, and social factors. Yoga is recommended as a nonmainstream treatment for many health conditions, including SUDs.
Methods: Five databases were searched for randomized controlled trials (RCTs) that evaluated yoga as an intervention in adults with any type of substance use disorder. The interventions being studied included Hatha yoga, Sudarshan Kriya yoga, breathing yoga exercises, and meditation. Studies, where yoga was combined with other interventions were excluded. The effect of yoga as an intervention was analyzed using primary outcomes such as anxiety, pain, and craving. Eight RCTs met the eligibility criteria, and quality analysis was conducted using the Cochrane criteria.
Results: Among the 8 final studies eligible for quality analysis, 2 had undefined substance use, while the others were focused on tobacco, alcohol, or opioids. Seven out of 8 studies showed significant results and improved primary outcomes such as anxiety, pain, or substance use. Seven out of the 8 studies showed significant positive outcomes using yoga in conjunction with other pharmacological treatment modalities like opioid substitution therapy.
Conclusions: Six out of 8 studies showed low concerns, while 2 studies showed some concerns about the risk of bias judgment. Although the results look encouraging, RCTs with larger sample size are needed to better evaluate the effectiveness of yoga as a treatment modality for substance use.
Background
Substance use disorder (SUD) is described in the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) as a “cluster of cognitive, behavioral, and physiologic symptoms indicating that the individual continues using the substance despite significant substance-related problems.”1 The etiology of SUD is characterized by complex interactions between genetic, environmental, developmental, and social factors still being studied today.2,3 On the individual level, SUD alters neurochemical pathways and behavioral patterns resulting in negative impacts on physical and mental health, such as poor sleep and nutrition, increased violence and trauma, and a higher risk of contracting a communicable disease.3,5,6 SUD is classified as mild, moderate, or severe, with the most severe form characterized by chronic and compulsive substance use.1 Traditional management of substance use disorder takes place in a specialized treatment program and typically includes a combination of pharmacological intervention, behavioral therapy, and supportive services.3 However, alternative treatments have become increasingly popular among patients due to increasing evidence of their effectiveness and the desire for treatment options outside traditional medicine.7
Yoga originated in India over 2 centuries ago and has since become increasingly incorporated into medical practice.8 Today, these practices are known as complementary and alternative medicine (CAM), defined by the National Center for Complementary and Integrative Health as a nonmainstream practice that is used together with conventional medicine or as a substitute for conventional medicine.9 In substance use disorder, CAM modalities studied include acupuncture, hypnotherapy, herbal medicine, mindfulness, music therapy, and yoga.7 Yoga, in particular, has been studied in SUDs as an effective alternative therapy and has been found to reduce stress and addictive behaviors while improving self-esteem and increasing self-control.10,11 The 2012 National Health Interview Survey (NHIS) showed that yoga was the third most common complementary health approach among adults.12 The overall structure of yoga includes specific breathing patterns (pranayamas), physical postures (asanas), relaxation, and meditation (focused thoughts and breathing) that act together to improve the mind and body.8 While the exact mechanisms of action are unclear, the use of yoga as a treatment for substance use disorder has been found to decrease addictive behaviors, enhance well-being, and improve cognitive flexibility.8,10,13 Assessing studies on yoga as an effective alternative therapy can provide information to clinicians seeking additional methods to reduce substance use and improve the quality of life in patients with substance use disorder.
There is a limited number of randomized control trials (RCTs) assessing the benefits of yoga, and many are underpowered and burdened by risk of bias due to small sample sizes.10 To our knowledge, only 1 systematic review of randomized control trials studying yoga in substance use disorder has been published in 2014.10 Therefore, in this systematic review, we explore and evaluate the most recently studied effects of yoga on adult patients with substance use disorder.
Methods
The systematic review included RCTs that studied the effect of yoga (including breathing and meditation) in adult patients 18 years and older with a substance use disorder. The trials published on or after January 2013 until the team conducted the literature search in January 2021 were included in this review. This study will provide evidence in continuation to the systematic review published in Focus on Alternative and Complementary Therapies, published in 2014.10 Studies where yoga was combined with other interventions were excluded. Nonrandomized, quasi-experimental or observational studies were excluded as well. The databases used for systematic search were MEDLINE, EMBASE, Cochrane Library, SCOPUS, and PsycINFO. The search methodology included keywords such as yoga, alternative treatment, substance use, addiction, drug dependence, alcohol use, and MeSH terms like Substance-Related Disorders. There were no additional articles found through manual search.
The data screening was independently conducted by 2 reviewers and verified by 2 other coauthors. In case of any disagreement in the screening between the 2 reviewers, it was resolved by the third and the fourth reviewers or via a consensus-based discussion. The data extraction was done by 3 reviewers using a preset data extraction form. The information was extracted on author name, publication journal and year, sample size, type of substance use disorder, comorbidities, if any, treatment details in intervention and control group, follow-up plan, outcome measures, conclusions, and biases reported. The quality of the trials, using The Cochrane tool ROB2,14 was assessed based on 5 domains, namely bias due to randomization process, deviations from intended interventions, missing outcome data, measurement of outcome, and selection of reported result. The overall score was reported as H = high risk of bias, S = some concerns, and L = low risk of bias.
Results
The search across the databases yielded a total of 488 manuscripts. After eliminating the duplicates and screening the abstracts, 8 studies met our eligibility criteria and were included in the review. Figure 1 describes the PRISMA flow diagram of the multiple steps involved in selection process. The data extraction form is summarized in Table 1.
Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Flow Diagram. Abbreviation: RCT, randomized control trial.
Data Extraction from the Eligible Studies
Lyons et al15 studied the effect of mindfulness (yoga and meditation) versus a communication skills session in 189 male prisoners (intervention arm = 88, control arm = 101) on preventing relapse in prisoners; 58% of the enrolled participants were African American with a mean age of 35.8 ± 11.3 years. Post-traumatic stress disorder (PTSD) and craving scores declined in both arms, and mindfulness increased. When controlled for Freiburg mindfulness pretest, decline in anxiety and PTSD was greater in the intervention group than the control group (P < .05). The authors concluded that the Mindfulness-Based Relapse Prevention (MBRP) program is a promising intervention adjunct to the substance use disorder treatment received in prison.
Uebelacker et al16 assessed the acceptability and feasibility of hatha yoga for chronic pain relief in 35 eligible participants (mean age in yoga and control group was 43 ± 10.7 and 44 ± 10.8 years, respectively) receiving treatment as usual (TAU) in the form of opioid agonist therapy for opioid use disorder. Participant mood improved pre-class to post-class (measured using a Likert scale survey to measure sadness, anxiety, irritability), with greater decreases in anxiety and pain for high attenders (those who attended 6 or more classes) in the yoga group (P < .05) as compared with those taking a health education class (see Table 2). The authors concluded that yoga could be delivered on-site at opioid agonist treatment programs with home practice taken up by participants.
Description of the Interventions and Their Results
Bock et al17 studied yoga as a complementary therapy for smoking cessation in 227 randomly selected people (yoga = 113, control = 114). The overall mean age of the participants was 46.2 ± 12. Participants in the Yoga intervention arm had 37% greater odds of achieving abstinence than the participants in the Wellness arm. A significant dose-response relationship was observed for Yoga (OR, 1.12, 95% CI, 1.09% to 1.26%), but not Wellness, such that each Yoga class attended increased odds of quitting at end of treatment by 12%. The authors concluded that Yoga seems to increase the odds of successful smoking abstinence, particularly among light smokers (≤ 10 cigarettes/day).
Wimberly et al18 studied the effect of hatha yoga for stress and substance use among 73 people (yoga = 37, TAU = 36) living with HIV in reentry from prison. At 3 months, yoga participants reported less stress (P < .05) and fewer days of substance use (P < .001) than participants in the control group receiving treatment as usual (case management, recreational or General Educational Development (GED) classes, and free health care) as seen in Table 2. The authors concluded that yoga interventions could provide a complementary treatment option for citizens returning from prison and experiencing HIV and substance use.
Sharma et al19 determined yoga and recreational activity as an avenue to prevent criminal propensity among 30 men (15 to 35 years) with substance use disorder. After 10 weeks, the findings revealed that there was a significant difference (P < .05) in all the treatment groups (group 1 = yoga; group 2 = recreational activity) when compared with the control group (no intervention), as seen in Table 2. The adjusted mean values of recreational activity (group 2) were found to be the least, indicating that this group was considered the most effective treatment group in reducing criminal propensity among individuals with substance use disorder. It was concluded that yoga and recreational activities have significant effect on lowering criminal propensity.
Sarkar et al20 evaluated the effectiveness of a brief community outreach tobacco cessation intervention (including yogic breathing) in 1213 randomly selected people (mean age of 46.3 ± 13.6 years) in India (refer to Table 1). The smoking cessation rate at 6 months post-intervention was found higher in the intervention group than in the control group (risk ratio [RR], 5.32; P < .05). Intention-to-treat analysis showed that the participants in the yoga group were 5 times more likely to be in abstinence at 6 months than those in the control group. The authors concluded that a single session of community outreach intervention could increase tobacco cessation in low to middle-income countries.
Dhawan et al21 measured the effectiveness of a yogic breathing intervention on quality of life (QOL) of 84 male participants (study group = 55, control group = 29) dependent on opioids. The mean age of the study and control group was 39.2 ± 10.4 and 37.0 ± 9.6 years, respectively. All 4 QOL domain scores, assessed using WHO Quality of Life (QOL) brief scale, were significantly higher at 6-month follow-up period. There was a significant increase in the intervention group's physical, psychosocial, and environment domains, while the control group showed significant changes in the social relationship domain only. They concluded that Sudarshan kriya yoga was a beneficial low-cost and low-risk adjunct therapy for improving QOL in substance treatment settings.
Reddy et al22 investigated the effect of yoga intervention on alcohol and drug misuse risk in 38 (yoga = 20, control = 18) veteran and civilian women (mean age, 44.4 ± 12.4) with post-traumatic stress disorder. The mean scores for alcohol use disorder identification test (AUDIT) and Drug Use Disorders Identification Test (DUDIT) decreased in the yoga group; in the control group, mean AUDIT score increased, and mean DUDIT score remained constant. 69% in the yoga group reported fewer PTSD symptoms, and 92% reported coping better with symptoms (P < .001).
Risk of Bias
Cochrane risk-of-bias tool for randomized trials (RoB 2)14 was used for quality review and assess the risk of bias in the eligible studies. Overall, 6 out of 8 studies showed low concerns, while 2 studies showed some concerns about the risk of bias judgment (Table 3). One study had some concerns about the risk of bias owing to the lack of information on the randomization process and missing outcome data. Another study had a concerning risk of bias due to assignment to intervention, and the analysis used to estimate the effect of the assignment.
Risk of Bias Judgement* (Green=Low, Yellow=Some Concerns, Red=High)
Discussion
Yoga has been used as a treatment for many health-related issues.23 This systematic review aimed to review up-to-date evidence and significant results from randomized trials conducted across the globe. The results showed that the studies included in this systematic review were undertaken mainly in the United States and India. Two eligible studies had undefined substance use, while the others were focused on tobacco, alcohol, or opioids. Some studies reported HIV or PTSD as a comorbidity in the sample population, while the others did not describe any concomitant health condition. Seven of the 8 studies showed significant results and improved outcomes in anxiety, pain, or substance use.
The studies included in this review were limited to randomized controlled trials to increase the internal validity of the results24 and provide comprehensive and reliable evidence for yoga as therapy in patients with substance use disorder. As shown in Table 2, studies showed yoga used as an intervention independently or as an adjunct to the other treatment plan improves outcomes. The interventions included Hatha yoga, Sudarshan Kriya yoga, breathing yoga exercises, and meditation. Hatha yoga is the practice of yoga postures along with breathing and meditation.25 Sudarshan kriya yoga, on the other hand, involves rhythmic cyclic breathing.26
The primary outcomes were measured using standardized and validated surveys for data collection such as AUDIT,27 and DUDIT,28 SAFTEE,29 QOL,30 and others. Although most of the studies were able to show significant results, lack of blinding in most of the studies was a limitation leading to low or some risk of bias.31 Seven out of the 8 studies showed significant positive outcomes using yoga in conjunction with other pharmacological treatment modalities like opioid substitution therapy. Most studies failed to report any adverse event. Although adverse events from RCTs have minimum implications in the real world, not reporting such events may question the safety of the intervention.
Globally, SUD is a major public health concern and has placed a significant economic burden on society.2 In the United States, costs associated with alcohol and other drugs total over $400 billion due to lost workplace productivity, health care costs, law enforcement, and other criminal justice costs.3,4 CAM has been shown to be a cost-effective treatment modality compared with conventional therapy alone in many medical conditions.32 Yoga, in particular, is a low to no-cost treatment option for patients. It has been shown to be a cost-effective treatment option for chronic back pain33 and other musculoskeletal conditions.34 The use of inexpensive alternative treatments, like yoga, as an adjunct treatment for substance use disorder may help lower the rising health care costs.
Limitations
This review had some limitations. Some relevant studies might have been excluded due to the chosen study design. Including randomized controlled trials in a review provides higher internal validity, but they are less generalizable than other study designs.35 In addition, data from the studies published in languages other than English were not included. Lastly, this review lacks measurement of the strength of association between the interventions and the outcomes. A meta-analysis in the future can provide a quantitative estimate of the effect of yoga as a treatment intervention.
Conclusion
Most of the studies included in this review had larger sample sizes than a similar review published in 2013. This updated review of randomized controlled trials provides strong evidence35 to include yoga as an effective complementary treatment modality in the management of patients with substance use disorder. Further studies comparing the effect of yoga on specific substances used should be conducted to study concrete evidence in using yoga as a main-line treatment for different types of substance misuse.
Notes
This article was externally peer reviewed.
Conflict of interest: The authors whose names are listed certify that they have no affiliations with or involvement in any organization or entity with any financial interest or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript.
Funding: This review supported by the Health Resources and Services Administration (HRSA) of the US Department of Health and Human Services (HHS) Grant number T32 HP10031. The contents are those of the author(s) and do not necessarily represent the official views of, nor an endorsement, by HRSA, HHS or the US Government.
To see this article online, please go to: http://jabfm.org/content/34/5/964.full.
- Received for publication April 21, 2021.
- Revision received June 14, 2021.
- Accepted for publication June 15, 2021.
