Summary of studies
| Study | Inclusion criteria | Exposure* | Outcome measure(s) | Results from study for primary outcome measure† | Comments |
|---|---|---|---|---|---|
| Note: values in italics were calculated post hoc as part of this review. | |||||
| *Values in parentheses are minus dropouts. | |||||
| †Values reproduced or calculated where data were sufficient, standardised mean differences calculated as per Hedges formula, bias corrected.39 | |||||
| ‡Without the assumption of equal variances.40 | |||||
| §Results included at three weeks only | |||||
| ¶Assumed values given were standard deviations rather than standard errors. | |||||
| **Results included for day of examination only. | |||||
| ††Results for cognitive and somatic anxiety groups combined. | |||||
| DSM-III-R, Diagnostic and statistical manual of mental disorders, third edition, revised; OCD, Obsessive compulsive disorder; SD, standard deviation; CI, confidence interval. | |||||
| Key for scales: ACL, anxiety check list; BSASI, Bell’s social adjustment scale; HAS, Hamilton anxiety scale; HDRS, Hamilton’s depression rating scale (HRSD, HAMD); IPAT, Institute for personality and ability testing (anxiety scale); KcIT, Knox-cube imitation test; LoC, locus of control; MMPI, Minnesota multiphasic personality inventory; PIL, purpose in life test; POMS, profile of mood states; PSLES, presumptive stressful life events scale; PSS, perceived stress scale; SCL-90-R OC and GSI, symptoms checklist-90-revised obsessive compulsive and global severity index; SNAQ, snake attitude questionnaire; SSI, symptom sign inventory; STAI, state-trait anxiety inventory; STAS, Spielberger’s test anxiety scale; SUD, subjective unit of disturbance; TAS, Taylor’s anxiety scale; Y-BOCS, Yale-Brown obsessive compulsive scale. | |||||
| Shannahoff-Khalsa et al22 (n = 22) | OCD. DSM-III-R diagnosis plus minimum of 15 on Y-BOCS for the adults. | Yoga treatment: kundalini yoga (includes specific OCD technique as well as mantra meditation) (n = 12) (7). Control: relaxation response and mindfulness meditation (n = 10) (7). Both were one hour weekly treatments with instructor plus daily practice. Trial duration: 3 months | Primary: Y-BOCS at baseline and after three months. Others: SCL-90-R (OC and GSI), POMS, PSS, and PIL | Significant between group mean difference (p = 0.047). Intention to treat analysis: significant reduction in mean for yoga group (p = 0.023) but not for control group (p = 0.058). Mean reduction: yoga group = 9.43 (SD 7.21) (−38.4%); control group = 2.86 (SD 3.13) (−13.9%). Mean difference = 6.57, 95% CI (0.10 to 13.0) p = 0.047 (p = 0.058‡). Standardised mean difference = 1.10, 95% CI (−0.02 to 2.22) | Methodology: randomisation: adequate. Allocation concealment: adequate. Blinding of assessors: unknown. Attrition rate: yoga, 41.7% (includes the one adolescent); control, 30% |
| Sharma et al28§ (n = 71) | Anxiety neurosis. Diagnosed with Feighner’s diagnostic criteria | Yoga treatment: Yoga (kapalabhati and ujjayi pranayama). One week training then twice daily practice for 10 min each time (n = 41) (33). Control: placebo capsule, once a day (n = 30) (24). Trial duration: 12 weeks | Primary: HAS at three weekly intervals. Others: SUD, various physiological measures and PSLES | Significant between group mean difference (p<0.005) at three weeks indicating greater improvement in yoga group than in control group (p<0.005). Significant improvement for yoga group between 3 and 6 weeks (p<0.01) but not for control group. Mean reduction: yoga group = 6.91 (SD 4.26) (−23.7%); control group = 3.71 (SD 2.18) (percentage change incalculable because of unreliable baseline figure). Mean difference = 3.20 95% CI (1.30 to 5.10) p = 0.001. Standardised mean difference = 0.89, 95% CI (0.34 to 1.44) | Methodology: randomisation: non-randomised. Allocation concealment: N/A. Blinding of assessors: unknown. Attrition rate: yoga, 19.5% at 3 weeks, 34.1% at 6 weeks; control, 20% at 3 weeks, 46.7% at 6 weeks; both increasing later. Clinical: anxiety neurosis is not a diagnosis used now. Follow up length seems appropriate |
| Sahasi et al23 (n = 91) | Anxiety neurosis. DSM-III diagnosis | Yoga treatment: yoga (consisting of sukhasna, talasna, pranayama, nishpand bhav, savasna). Daily practice, 5 days a week instructed, 2 days home practice, 40 min duration (n = 38) (30). Control: diazepam (no dose or frequency given) (n = 53) (18). Trial duration: 3 months | Primary: IPAT at baseline and after 3 months. Others: SSI, LoC, and KcIT | Mean changes significant for yoga group (p<0.05) but not for diazepam group (p>0.05). Mean reduction: yoga group = 3.39 (SD 6.81); control group = −0.36 (SD 8.58). Mean difference = 3.75, 95% CI (−0.76 to 8.26) p = 0.101. Standardised mean difference = 0.49, 95% CI (−0.10 to 1.08) | Methodology: randomisation: inadequate. Allocation concealment: inadequate. Blinding of assessors: unknown. Attrition rate: yoga, 21.1%; control, 66.0%. Clinical: anxiety neurosis is not a diagnosis used now |
| Vahia et al24 (n = 27) | Psychoneurosis. Diagnosed (method not stated) | Yoga treatment: five steps: asana, pranayama, pratyahara, dharana, and dhyana (n = 15). Control: relaxation with postures resembling Asanas and breathing practices resembling Pranayama plus writing (n = 12). Both groups were given placebo tablets. Both practised daily, 1 hour, 6 days a week. Trial duration: 4 weeks minimum | Primary: TAS (weekly, including before and after treatment). Others: Rorschach and MMPI | Significant difference between group means after (p<0.001) but not before treatment (p = 0.17). Reduction in mean for yoga group but not control. Concludes significance at 5% level. Mean reduction: yoga group = 6.66 (−26.1%); control group = −0.50 (+1.7%). Mean difference = 7.16 | Methodology: randomisation: unknown. Allocation concealment: unknown. Blinding of assessors: adequate. Attrition rate: unknown. Clinical: psychoneurosis is no longer used as a diagnosis |
| Vahia et al29 (n = 39) | Psychoneurosis or psychosomatic disorder. Diagnosed (method not stated) | Yoga treatment: as Vahia et al28 (n = 21). Control: anxiolytic and antidepressant drugs (amitriptyline and chlordiazepoxide), variable dosage schedule (n = 18). Trial duration: 6 weeks | Primary: TAS (initial (pre), intermediate and final (post) evaluations). Others: HDRS and BSASI | Significantly greater pre-post reduction in scores for yoga group than for control group (p<0.05) | Methodology: randomisation: non-randomised. Allocation concealment: N/A. Blinding of assessors: adequate. Attrition rate: unknown |
| Broota and Sanghvi25 (n = 30) | Examination anxiety (high score on STAS) plus history of examination anxiety | Yoga treatment: Broota relaxation technique (exercises adapted from yoga combined with autosuggestion) (n = 10). Control 1: Jacobson’s progressive relaxation technique (n = 10); control 2: talking only (n = 10). All were practised on consecutive days, 20 min duration each. Trial duration: 3 days | Primary: ACL at baseline (pre) and after 3 days (post). Others: self evaluation ladder scale (anxiety measure) | Significant difference between the three groups on the pre-post changes (p<0.01). Mean of the pre-post changes for Broota group significantly greater than Jacobson group (p<0.05) and talking control group (p<0.01) | Methodology: randomisation: unknown. Allocation concealment: unknown. Blinding of assessors: not blinded (self assessed). Attrition rate: “many” dropouts for the control group. Clinical: role of author – Broota – in study not clear |
| Malathi and Damodaran26 (n = 50)¶** | Examination anxiety anticipated because of impending examination | Yoga treatment: yoga based intervention (various asanas, plus prayer, exercises, visualisation, and meditation) (n = 25) Control: work such as reading and writing (n = 25). Both were practised for 1 hour, 3 times a week Trial duration: 3 months | Primary: STAI at pre and post practice, one month before exams and on the day of the examination | Significant pre-post reduction in mean for yoga group 1 month before examination and on day of examination (p<0.001 for both), no such significant reduction for the control group. Mean reduction on day of examination: yoga group = 15.91 (−34.0%); control group = −1.55 (+3.4%). Mean difference = 17.46 | Methodology: randomisation: unknown. Allocation concealment: unknown. Blinding of assessors: not blinded (self assessed). Attrition rate: unknown |
| Norton and Johnson27†† (n = 40) | Snake phobia (moderate) identified by SNAQ responses | Yoga treatment: slightly modified form of Agni yoga (n = 20). Control: progressive relaxation (n = 20). Phase 1: both were practised for 4 sessions (45 min each) plus home practice. Total duration: 3 weeks. Phase 2: one 15 min practice then one off approach of snake. Variable scheduling dependent on participant’s convenience | Primary: SNAQ at baseline (before phase 1) and after phase 2. Others: relaxation score (phase 1), approach score, pulse rate, and subjective fear (phase 2) | Significant group by treatment interaction on post phase 2 SNAQ (p<0.05). No significant simple main effects on post phase 2 SNAQ. Reduction for yoga group = 4.99(−12.7%); control group = 3.20(−8.6%). Mean difference = 1.79 | Methodology: randomisation: unknown. Allocation concealment: unknown. Blinding of assessors: not blinded (self assessed). Attrition rate: unknown Clinical: clinical relevance questionable |