Edited by: Susan A. Everson-Rose, University of Minnesota, USA
Reviewed by: Dusan Kolar, Queen’s University, Canada; Felicia Iftene, Queens University, Canada
*Correspondence: Meera Balasubramaniam, Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC, USA. e-mail:
This article was submitted to Frontiers in Affective Disorders and Psychosomatic Research, a specialty of Frontiers in Psychiatry.
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.
Mental illnesses are asignificant global health concern, despite improvements in treatment modalities and access to care. The World Health Organization (WHO,
The availability of psychopharmacological treatments has increased, but the response and tolerability remain unpredictable and inconsistent. While psychotropics agents can be lifesaving for many people, there remains a considerable unmet need. The landmark National Institute of Mental health (NIMH) funded Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study showed remission in only one third of major depression patients after a trial with the first anti-depressant and worsening response rates with each subsequent trial (Trivedi et al.,
Given the heterogeneous nature of psychiatric conditions, with respect to biological, psychological, and social factors, it is not surprising that available standard treatments often have inconsistent response rates. The quest and demand for non-pharmacological treatment modalities has been increasing (Barrows and Jacobs,
Yoga, with origins in ancient India has several sub-types (Table
Type of yoga | Key features |
---|---|
Ashtanga yoga | Fast-paced series of sequential posture, based on six series of asanas |
Hatha yoga | Basic form of yoga which incorporates postures, regulated breathing, and meditation |
Iyengar yoga | Focuses on the precise alignment of postures |
Power yoga | Westernization of Ashtanga yoga. Popular in the US |
Jivamukti yoga | Physically challenging postures, highly meditative |
Kali Ray TriYoga | Consists of flowing, dance-like movements, often accompanied by music |
White Lotus Yoga | Consists of flowing movements with varying difficulty levels |
Integrated yoga therapy | Designed for medical problems. May include meditation and guided imagery |
Viniyoga | Gentle practice which particularly emphasizes on the synchronization of poses with breathing |
Svaroopa | Emphasizes on the “opening of the spine beginning at the tailbone progressing through each spinal area” |
Bikram Yoga (Hot Yoga) | Consists of a series of 26 postures performed in a space with temperature above 100°F |
Phoenix rising yoga therapy | Combines traditional yoga with client centered and mind-body psychology, that incorporates non-directive dialog |
Sivananda yoga | Consists of 12 basic yoga postures along with chanting and meditation |
Integral yoga | Consists of basic hatha yoga postures |
Ananda yoga | Consists of basic hatha yoga postures with use of “silent affirmations while holding up a pose” |
Kundalini yoga | Focuses on awakening the energy at the base of the spine and channeling it upwards |
ISHTA yoga | Combination of Ashtanga and Iyengar yoga |
Kripalu yoga | Consists of three stages namely willful practice, willful surrender, and meditation in motion |
Anusara yoga | Consists of basic hatha yoga postures but emphasizes on |
Tibetan yoga | Composed of fine, flowing movements, and controlled breathing |
Thus, while the effects of yoga on the spiritual aspects of the mind (e.g., inner peace) are well documented, its effects in major clinical psychiatric disorders are less so. The objective of this report was to systematically review the available literature for the effects of yoga on major psychiatric disorders. The focus of this review was primarily categorical disease threshold outcomes (e.g., major depression), in keeping with how psychiatric disorders are categorized and treated, and how effects of psychopharmacologic interventions are assessed – rather than on single symptom domains such as mood or sleep which cut across multiple diagnoses. We did use symptoms (e.g., depression and memory) as search terms to ensure our search was comprehensive but restricted our final review to major disorders that require intervention in practice.
Electronic searches of The Cochrane Central Register of Controlled Trials (CENTRAL) and the standard bibliographic databases, MEDLINE, EMBASE, and PsycINFO, was conducted through April 2011 and updated in June 2011, using the keywords yoga AND psychiatry OR depression OR anxiety OR schizophrenia OR cognition OR memory OR attention AND randomized controlled trial (RCT). The title and abstract of each citation were screened based on definite pre-specified inclusion and exclusion criteria. Full text reading of articles that were potentially eligible was undertaken. When full-texts were not available, attempts were made to contact the author. If a reply was not received within 2 weeks from the corresponding author, abstracts were read to check if they had the required information. Studies have been reviewed by all authors and disagreements were resolved by consensus.
Randomized clinical trials with any sub-type of yoga as the intervention and one or more of the above mentioned conditions as the outcome of interest were included. Open trials, non-randomized trials, case series, and dissertations were excluded. The review includes studies in which subjects have either been formally diagnosed with a disorder or have reported symptoms suggestive of the same. Since age is an important risk factor for cognitive impairment, studies examining cognition in the geriatric population have been included, even in the absence of formal diagnoses or specific symptoms. Studies on sub-threshold symptoms such as general well-being, stress, and coping have been excluded. Outcomes consisted of self-reported change, scores on rating scales, acceptability, and tolerance of the treatment.
The quality of RCTs was scored using the guidelines recommended by the Agency for Healthcare Research and Quality (AHRQ,
Item | Points |
---|---|
Study question – clearly focused? | 1 |
Study population | 2 |
Randomization | 2 |
Blinding | 2 |
Interventions | 2 |
Outcomes | 2 |
Statistical analysis | 2 |
Results | 1 |
Discussion (including limitations and biases) | 1 |
Funding source | 2 |
Total | 17 |
Score | 100% |
Evidence level | Study design |
---|---|
1 | High quality RCTs with narrow confidence intervals |
2 | Low quality RCTs or high quality cohort studies |
3 | Case-control studies |
4 | Case series or poor case-control studies or poor cohort studies or case reports |
Term | Level | Evidence levels | Explanation |
---|---|---|---|
Recommended | A | 1 or 2 | Assessment supported by a substantial amount of high quality (levels 1 or 2) evidence and/or based on consensus of clinical judgment |
Suggested | B | 1 or 2 – few studies |
Assessment supported by sparse high grade (Level 1 or 2) data or a substantial amount of low grade (level 3 or 4) data and/or clinical consensus |
May be considered | C | 3 or 4 | Assessment is supported by low grade data without the volume to recommend more highly and likely subject to revision with further studies |
Sixteen RCTs met criteria for inclusion in our review. Figure
Four RCTs examining the effects of yoga on depression have been included in this review. Table
Study | Sample | Treatment groups | Intervention | Duration | Outcome measurements | Findings | RCT | Evidence level |
---|---|---|---|---|---|---|---|---|
Shahidi et al. ( |
70 depressed women aged 60–80 years from a cultural community in Iran with Geriatric Depression Scale score > 10 | Laughter yoga ( |
Laughter yoga consisted of brief talk about something delightful, clapping hands, simple chants simulating diaphragmatic breathing, Gibberish sounds. Combines yoga, breathing, and stretching techniques | 10 sessions | Yesavage Geriatric Depression Scale and Diener Life Satisfaction Scale (LSS) | Significant improvement in GDS scores in both laughter and exercise groups compared to controls but not when compared to each other | 13 (not double blinded, funding information not given) | 2 (Low quality RCT due to insufficient follow-up) |
Krishnamurthy and Telles ( |
69 participants (males and females), older than 60, living in a residential home | Stratified sampling and random allocation to yoga, ayurveda, wait-list control groups | Yoga consisted of 7 h 30 min weekly sessions of physical postures, relaxation techniques, regulated breathing, devotional songs, and lectures | 24 weeks | Shortened version of Geriatric Depression Scale (GDS) | The yoga group showed significant decrease in depression at 3 and 6 months compared to the ayurveda group | 13 (not double blinded, funding information not given) | 2 (Low quality RCT due to <80% follow-up rate) |
Vedamurthachar et al. ( |
Males aged 18–55 years with alcohol dependence, admitted for the first time to the de-addiction center of NIMHANS, not having serious medical illnesses, schizophrenia, or mania | SKY – Sudarksha Kriya yoga ( |
SKY consisted of practice of three distinct breathing patterns | 2 weeks | BDI scores, ACTH, and cortisol levels | Statistically significant decrease in BDI scores in the SKY group compared to controls. Greater reduction in serum cortisol and ACTH levels in the SKY group | 15 (not double blinded) | 2 (Low quality RCT due to insufficient follow-up) |
Woolery et al. ( |
28 volunteers aged 18–29 years, with self-reported symptoms of depression, but not on psychotropic treatment and without previous exposure to yoga | Yoga ( |
1 h weekly Iyengar yoga classes, consisting of training in yoga postures | 5 weeks | BDI, State-Trait Anxiety Inventory, Profile of mood states, morning cortisol levels | Statistically significant decrease in BDI scores, anxiety scores, and higher morning cortisol levels in the yoga group | 13 (not double blinded, funding information not given) | 2 (Low quality RCT due to insufficient follow-up) |
Shahidi et al. tested 70 elderly women (mean age of 65 years in the intervention groups and 68 years among controls) reporting subjective symptoms of depression with a baseline score of >10 on the Geriatric Depression Scale (GDS) and suggested that 10 sessions of laughter yoga or exercise resulted in significant improvement of depressive symptoms from baseline and compared to a wait-list control group; however the two active treatment groups did not differ from each other (Vedamurthachar et al.,
In a 24-week study comparing the effects of yoga (7 h weekly) to Ayurveda and wait-list controls among 69 elderly individuals (mean age of 72 years), with self-report of symptoms consistent with depression and baseline mean scores on GDS corresponding to mild illness severity who were not on psychotropic medications, Krishnamurthy et al. reported that in the yoga group, there was a reduction in the scores on the GDS, from the baseline mean score of 10.6 by approximately 20% at 3 months and 40% at 6 months, a change from mild depression to no depression. This was statistically superior to the Ayurveda and wait-list control groups, neither of which demonstrated significant reduction in scores. The main limitations were the potential group interaction benefits of the yoga activity, lack of formal diagnoses according to criteria specified by the Diagnostic and Statistic Manual of Mental Disorders (DSM), relatively modest sample size, and the inclusion of only mildly depressed individuals making it difficult to generalize to more ill patients or to home based yoga (Krishnamurthy and Telles,
In a study of depression in 60 alcohol dependents males (mean age of approximately 35 years). Vedamurthachar et al. demonstrated that subjects undergoing de-addiction treatment had a statistically significant reduction in their scores on the Beck Depression Inventory (BDI), and concurrent reduction in serum cortisol levels when they received Sudarshan Kriya yoga (SKY) compared to their counterparts receiving routine inpatient care (Vedamurthachar et al.,
A fourth study focused on treatment naive young adults (mean age of 21.5 years) with self-reported symptoms of depression and scores in the “mild mood disturbance” range on the BDI (Woolery et al.,
None of the studies encountered adverse events in the yoga group though it was not always clear how systematically they were sought for. The drop-out rates were 0% (Vedamurthachar et al.,
Three RCTs examining the effects of yoga on schizophrenia have been included in this review. Table
Study | Sample | Treatment groups | Intervention | Duration | Outcome measurements | Findings | AHRQ | Evidence level |
---|---|---|---|---|---|---|---|---|
Visceglia and Lewis ( |
Clinically stable patients with schizophrenia, Schizoaffective disorder, with or without PTSD, Axis II pathology admitted to a state psychiatric facility | Yoga ( |
Yoga consisted of breathing exercises, warm-ups, and postures, conducted for 45 min twice weekly | 8 weeks | PANSS, WHO – quality of life – BREF | Significant improvement in total PANSS, positive syndrome, negative syndrome, general psychopathology. Superior outcomes in physical health and psychological health components of WHO-QOL-BREF | 15 | 2 (Low quality RCT due to limited duration of follow-up) |
Behere et al. ( |
Outpatients with schizophrenia stabilized on anti-psychotics for at least 6 weeks | Yoga ( |
Yoga module developed by SVYASA consisting of physical postures, breathing exercises, pranayamas. Training for 1 month followed by 2 months of home practice | 3 months | PANSS, SOFS, and TRENDS | Significant improvement in positive symptoms, negative symptoms, facial emotion recognition deficits, and socio-occupational functioning in the yoga group in the second and fourth month compared to baseline | 15 | 2 (Low quality RCT since between treatment analysis data not available) |
Duraiswamy et al. ( |
Schizophrenics in the outpatient and inpatient program in aged 18–55 years. Patients were moderately ill, on anti-psychotic medications for months, and on the same drugs for at least 4 weeks | Yoga ( |
Yoga consisted of asanas, breathing practice, relaxation techniques, and |
4 months | PANSS, SOFS 24 (Social and Occupational Functioning Scale, Simpson Angus scale for extra-pyramidal symptoms, AIMS, WHO – quality of life – BREF. Done at baseline and at the end of 4 months | PANSS total and sub-scores, SOFS score reduced significantly in both groups. Statistically significant difference in negative but not positive symptom scores between the yoga and exercise groups | 13 (not double blinded, funding information not given) | 2 (Low quality RCT since <80% follow-up rate) |
Behere et al. compared the adjunctive effects of yoga with exercise wait-list controls in their 3 month study of 91 anti-psychotic stabilized adult outpatients with schizophrenia with baseline Clinical Global Impression (CGI) score less than or equal to 3. The authors reported reduction in PANSS positive and negative symptom scores by 17 and 20%, respectively, statistically superior to the other two groups, as well as significant improvements in facial emotion recognition deficits, and socio-occupational functioning. Significantly higher baseline scores in the PANSS negative sub-scale and facial emotional recognition deficit in the yoga group, variation in the amount of yoga practice at home during the last 2 months of the study, limited follow-up are drawbacks of this study, and the inclusion of stable outpatients limit its generalizability to more severely ill individuals (Behere et al.,
In a study of 61 anti-psychotic stabilized (mean dose of around 470 mg/day in Chlorpromazine equivalents) inpatients and outpatients (mean age around 32 years) with schizophrenia (CGI illness severity score of 4.8 and 5.2 in the yoga and control groups) Duraiswamy et al. compared the effects of yoga with exercise, as adjuncts to anti-psychotic medications. Participants were taught yoga and exercise for 3 weeks, followed by encouragement of continued practice with monitoring of adherence. The authors reported a reduction in the total PANSS score by 25.09 points, corresponding to a moderate-to-large effect size of 0.74 in the yoga group, a greater reduction in the negative sub-scale (7.71 points, from a baseline of 21.9), but no statistically significant change between the two groups in the positive sub-scale. The yoga group demonstrated an improvement of socio-occupational functioning, with an effect size of 0.48 in the Socio-Occupational Functioning Scale (SOFS). Notable limitations of the study include its modest sample size and unclear assessment of continued home practice of the interventions (Duraiswamy et al.,
There were no adverse events, attributable to yoga reported in any of the studies, although it is not clear how this assessment had been performed. It is difficult to separate the effects of yoga from the benefits of group interaction. Assessments of change in the dose of anti-psychotics, relapse rates, and hospitalization rates have not been performed in any of the existing studies. Based on our assessment of the available literature according to the RAND/UCLA Appropriateness method, Grade B evidence supporting a potential benefit for yoga as an adjunct to anti-psychotic treatment in chronic schizophrenia.
Two RCTs examining the effects of yoga on Attention-Deficit Hyperactivity Disorder (ADHD) have been included in this review (Table
Study | Sample | Treatment groups | Intervention | Duration | Outcome measurements | Findings | RCT score | Evidence level |
---|---|---|---|---|---|---|---|---|
Haffner et al. ( |
19 children diagnosed with ADHD, with the exclusion of those with severe developmental disabilities, IQ < 70, and severe behavioral disturbances | Yoga and a control group consisting of conventional motor exercises. Cross-over design (YE and EY). Subjects were continued on their medications or complementary therapy | Two hourly sessions of Hatha yoga per week for 8 weeks, followed by a 6-week training break and 8 weeks of conventional motor exercises | 34 weeks | Parent, teacher ratings of ADHD (FBB-HKS) test scores on an attention task (DAT). Measurements done before an intervention, between interventions, and after the second intervention | Yoga was superior to conventional training with effect sizes between 0.60 and 0.97. Treatment more effective in children on medications | 13 (not double blinded, funding information not given) | 2 |
Jensen and Kenny ( |
16 boys diagnosed with ADHD according to DSM-IV criteria and on medications. Included children with co-morbid anxiety and learning disorders but excluded those with previous diagnoses of Oppositional defiant disorder and Conduct Disorder | Yoga group ( |
20 weekly yoga sessions lasting for an hour each. Yoga consisted of respiratory training, postural training, relaxation training, and concentration training ( |
20 weeks | Conners Parent and Teacher Rating Scales. (CPRS and CTRS) | Yoga group showed significant improvement on five sub-scales of CPRS (Oppositional, Global Index total, Global Index emotional lability, and Global Index Restless/Impulsive, ADHD Index) Control group showed improvement on three different sub-scales (Hyperactivity, Anxious/shy, and Social problems) Both groups improved significantly on CPRS perfectionism, DSM-IV hyperactive/impulsive, and DSM-IV total. No significant change on CTRS | 13 (not double blinded, funding information not given) | 2 |
Jensen et al. compared the effects of yoga with a control group comprising of games incorporating talking, listening, and sharing equipment for 20 weeks in their cross-over study of 16 children (mean age of 10.63 and 9.35 years in the yoga and control groups), diagnosed with ADHD according to DSM-IV criteria and continued on pharmacotherapy. They reported significant post-intervention improvement in scores on the Conners’ Parent Rating Scales (CPRS), namely the Oppositional (Cohen’s
Neither study has reported adverse events in the yoga group, although it is not clear how side effect assessment was performed. Details of pharmacotherapy for ADHD, change in dose during the course of the study have not been provided. Based on our assessment of the available literature according to the RAND/UCLA Appropriateness method, Grade B evidence supporting a potential benefit for yoga as an adjunct to pharmacotherapy in ADHD in children.
Two RCTs examining the effects of yoga on eating disorders have been included (Table
Study | Sample | Treatment groups | Intervention | Duration | Outcome measurements | Findings | RCT | Evidence level |
---|---|---|---|---|---|---|---|---|
McIver et al. ( |
90 women aged 25–63 from a community meeting criteria for Binge eating disorder, BMI > 25 | Yoga ( |
60 min weekly sessions (pranayama + hatha yoga + nidra yoga) | 12 weeks | Primary – BES Secondary – IPAQ BMI, hips, and waist measures | Statistically significant reductions in binge eating and increase in physical activity in the yoga group | 13 (not double blinded, funding information not given) | 2 (<80% Follow-up) |
Mitchell et al. ( |
113 women who responded to advertisements calling for women dissatisfied with their bodies | Cognitive dissonance ( |
Weekly for 45 min | 6 weeks | EDDS, BES, STAI, CES-D, EDI, IBSS-R, TFEQ, TAS-20, and BSQ-R-10 | No differences between the yoga and control groups. Significant improvements in the dissonance groups on the ED-BD, ED-DFT, EDDS, BSQ-R-10, STAI, and TAS | 15 (not double blinded) | 2 |
The second study in this group included 113 women (mean age of 19.56 years) reportedly “dissatisfied with their bodies,” recording mean baseline scores on the Eating Disorder Diagnostic Scale (EDDS) of 26.34, 30, and 22.55 in the yoga, cognitive dissonance therapy, and wait-list control groups, respectively, where a score > 16.5 is strongly suggestive of illness. The authors used a number of outcome measurements (see Table
Study | Sample | Treatment groups | Intervention | Duration | Outcome measurements | Findings | RCT | Evidence level |
---|---|---|---|---|---|---|---|---|
Chen et al. ( |
Community-dwelling, ambulatory, adults of mean age of 69.2 years, without previous training in yoga, cognitively alert, and independent or mildly dependent in self-care | Silver yoga ( |
Silver yoga exercises lasting for 70 min, conducted three times a week. Consisted of warm-up, postures, hatha yoga, relaxation, and guided imagery meditation | 6 months | PSQ1 (Chinese version), TDQ (Taiwanese Depression Questionnaire), SF-12 health survey, and (Chinese version) | At 3 and 6 months, significantly better scores on PSQI and less depression were found in the yoga group compared to baseline and compared to controls | 15 (not double blinded) | 2 (Low quality RCT since the SD was large) |
Manjunath and Telles ( |
69 residents from a home for the aged, stratified on the basis of age | Yoga ( |
Yoga consisted of physical postures, relaxation techniques, regulated breathing, and exercises on yogic philosophy | 6 months | Sleep latency, duration, awakenings, feeling of being rested, and day-time napping. Assessed at baseline, 3, and 6 months | Yoga group showed a significant decrease in sleep latency, increase in sleep duration compared to baseline. Between treatment effects were not significant | 15 (not double blinded) | 2 (Low quality RCT due <80% follow-up rate) |
Cohen et al. ( |
39 adult patients with lymphoma who were undergoing or had completed treatment in the past 12 months | Tibetan Yoga ( |
Tibetan Yoga consisted of controlled breathing, visualization, mindfulness, and postures | 7 yoga sessions | PSQI, Impact of Events Scale, STATE, CES-D, and Brief Fatigue Inventory | Tibetan yoga group showed statistically significant improvement in sleep latency duration, quality, and the total score, but none of the other outcomes | 13 (not double blinded, funding information not given) | 2 (Low quality RCT due to insufficient follow-up) |
Three RCTs examining the effects of yoga on sleep complaints have been included in this review (Table
In a study conducted at a home for the aged in India, Manjunath et al. compared the effects of 6 months of training in yoga versus an ayurvedic preparation on 69 elderly subjects (mean age of 70.1, 72.1, and 72.3 in the yoga, ayurveda, and wait-list control groups) with self-report of sleep impairment, but the absence of formal diagnosis of a sleep disorder at baseline. The authors reported a mean reduction in sleep latency of approximately 10 min and an increase in duration of approximately 60 min in the yoga group, a significant finding compared to the two control groups, neither of whom demonstrated comparable improvement. Of note, the sleep latency was fairly high at 25.83 min in the yoga group, even at the end of the study. The modest sample size, absence of formal DSM diagnoses, the presence of statistical significance within treatments but not between treatments for sleep latency are notable limitations (Manjunath and Telles,
Cohen et al. examined the effects of seven weekly sessions of Tibetan yoga (which combined training in breathing, relaxation, and postures with guided imagery), comparing it to wait-list controls on 39 adults (mean age of 51 years) with lymphoma who were either receiving chemotherapy or had received it within the past 1 year. Participants reported subjective sleep impairment and recorded baseline PSQI scores of 6.5 and 7.2, respectively, in the yoga and control groups, corresponding to “poor sleep quality” according to scoring guidelines. Formal DSM diagnoses of insomnia had not been established. The yoga group demonstrated a statistically superior reduction in the total PSQI score, a reduction from a mean of 6.5 to 5.8, compared to controls who recorded a mean score of 8.1 at the end of the study. Scores of sleep quality (improved from 0.90 to 0.85), latency (improved from 1.10 to 0.75), and duration (improved from 0.85 to 0.89) were favorable in the yoga group, whereas the controls did poorly on all of the above parameters. The yoga group, but not controls showed a statistically significant reduction in the need for sleep aids – details of agents used and doses have not been specified. While there was improvement in sleep related parameters, depression, and state anxiety did not change. The modest sample size, unclear distinction between primary sleep disorders and those secondary to a mood, or anxiety disorder are drawbacks of this study (Cohen et al.,
None of the studies reported adverse effects attributable to yoga, although it is not clear how they were assessed. Based on our assessment of the available literature according to the RAND/UCLA Appropriateness method, Grade C evidence supporting a potential benefit for yoga exists for sleep complaints.
Two studies have been included in this review, the details of which can be found on Table
Study | Sample | Treatment groups | Intervention | Duration | Outcome measurements | Findings | RCT score | Evidence level |
---|---|---|---|---|---|---|---|---|
Sharma et al. ( |
30 individuals aged 18–55 years with MDD, on anti-depressants | Sahaja yoga + medications ( |
Details not specified | 8 weeks | Neurocognitive tests (LCT, TTA, TTB, RFFT, FDS, and RDS) | Significant improvement in LCT, TTA, TTB in both groups. Greater improvement in LCT in yoga group. Significant improvement in RDS scores only in yoga group | Abstract | Not assessed since full text was not available |
Oken et al. ( |
135 men and women aged 65–85 years. Excluded patients with severe medical problems, alcoholism, and drug dependence. Baseline level of cognitive function not specified | Hatha yoga ( |
Iyengar yoga postures, classes were conducted for 90 min every week along with home practice. Progressive relaxation, visualization, and meditation techniques were introduced | 6 months | Stroop color and word tests, quantitative EEG measure of alertness (posterior median frequency) | No significant difference in measures of cognition | 15 (not double blinded) | 2 (results not statistically significant) |
In a study of 135 elderly individuals (mean age of 71.5, 73.6, and 71.2 in the yoga, exercise, and wait-list groups, respectively). Oken et al. compared the effects of yoga with exercise and wait-list controls over 6 months, focusing on measures of alertness using EEG and the Stroop Color and word tests. Baseline cognitive assessments are not reported to have been performed; individuals with severe medical illnesses were excluded, as were those with experience in yoga over the last 6 months. Significant changes in measures of cognition were not demonstrated in any of the groups. The yoga group did demonstrate improvement in quality of life measures related to a sense of well-being as physical measures such as forward flexibility and timed one leg standing. The negative results notwithstanding, the absence of specification of baseline cognitive status is a drawback of this study (Oken et al.,
To our knowledge, this is the first review to systematically examine the published literature on benefits of yoga for several major psychiatric illnesses. Based on our assessment of the available literature according to the RAND/UCLA Appropriateness method, Grade B evidence supporting a potential acute benefit for yoga exists in depression (four RCTs), as an adjunct to medications in Schizophrenia (three RCTs) and ADHD (two RCTs), and Grade C evidence supports the benefit of yoga for sleep complaints (three RCTs).
Studies have found reasonable benefit in mild depression, even in the absence of pharmacotherapy. Studies of yoga in schizophrenia have yielded evidence of benefit as an adjunct to medications in improving positive and negative symptoms, quality of life, and socio-occupational functioning. The RCTs examining yoga in ADHD have demonstrated moderate-large effect sizes, comparable according to the authors, to other alternative therapies such as biofeedback and relaxation in ADHD (Haffner et al.,
Although yoga has been used as a treatment for a wide variety of psychiatric conditions and distress, we have focused on the major broad categories of psychiatric disorders, namely depression, schizophrenia, eating disorders, ADHD, sleep complaints, and cognitive impairments. We excluded studies on sub-threshold symptoms such as coping, general well-being as well as studies conducted on individuals without psychiatric diagnosis. This was done to minimize the possibility that observed effects are merely a reactive change to a new event in normal individuals. Our search term “anxiety” yielded studies on post-traumatic stress, state, and trait anxiety but these studies had specifically excluded individuals with pre-established psychiatric diagnoses and hence did not make it to the final review.
Few studies have provided details on how randomization had been performed. Studies included in our review consist of various sub-types of yoga and the description of the intensity of yoga has not been specified in many studies. The number of studies for each sub-type of yoga is very small, therefore, for the purpose of our review, which is the first of its kind, we considered sub-types which included similar basic components, namely controlled breathing, relaxation, and postural training to be equivalent. Due to the nature of the intervention, blinding of subjects is challenging, while information regarding blinding of the assessor has not been provided in most studies. Analogous to other interventions such as exercise, where they may be effects of group intervention, it is difficult to isolate benefits of being in a group from that derived from yoga alone in our studies. This may be particularly the case in studies with wait-list controls, where it is difficult to establish if the observed changes are due to the effect of yoga or merely expectation. The sample sizes are small in many studies and the generalizability of benefits noted in participants who demonstrate the motivation to participate and comply in studies of yoga may be questionable. The severity of illness has varied across studies, and it is of concern if the findings from results of mildly ill individuals (such as the depression studies) can be extrapolated to those with severe illness. Although adverse effects have not been reported in these studies, details of how the assessment had been done are lacking.
Our systematic review finds emerging scientific evidence to support a role for yoga in treating depression, sleep complaints consistent with both popular beliefs and biological studies, and having adjunctive value in schizophrenia and ADHD. The evidence in other disorders remains less well established. Given the growing popularity of yoga, it would be important for the field to attempt to replicate and extend these findings in larger, multi-center, randomized, blinded (at least single blinded) studies with the control group receiving alternative treatments, preferably using Good clinical practice (GCP) guidelines. Biomarker research, such as through functional magnetic resonance imaging (MRI) and Positron Emission Tomography (PET) studies, and molecular markers (genomics, metabolomics, and proteomics), would facilitate greater scientific understanding at a neurobiological level, of this 5000-year-old revered practice.
P. Murali Doraiswamy has received research grants and/or advisory fees/honoraria from several government agencies, media, and pharmaceutical companies. He owns stock in Sonexa and Clarimedix.