Study designs of evaluations included in the review
Only randomised controlled trials (RCTs) were eligible for inclusion in the review.
Specific interventions included in the review
Studies comparing TM (using the technique as taught by Maharishi Mahesh Yogi) with a control treatment (no treatment, sham treatment, or alternative treatment) were eligible for inclusion. Studies where the effect of TM might be confounded by other practices or advanced TM techniques were not included. The control treatments in the included studies were mindfulness training, mental relaxation, progressive muscle relaxation, life-style modification education, cognitive-based stress control, a diet and exercise programme, or no treatment.
Participants included in the review
No inclusion criteria in terms of the participants were specified for the review. The included studies were of elderly volunteers (mean age 81 years); African-Americans with mild hypertension (aged 55 to 85 years); African-Americans aged 15 to 18 years with upper-normal BP; African-Americans with hypertensive heart disease; and normotensive men (mean age 25 years).
Outcomes assessed in the review
The primary outcome in the review was the cumulative effect on BP after an extended period of intervention. Assessment of BP during a TM session was not an outcome of the review; studies that reported only this acute outcome were excluded.
How were decisions on the relevance of primary studies made?
One author selected papers for the review and a second reviewer checked that none of the excluded studies should have been included.