Examining randomised controlled trials exploring meditation in my review, control methods were presumptively categorized according to their face-validity into low, moderate or high face validity categories.

The low face-validity controls used strategies that were:
Passive and unstructured: Participants were involved in minimal or no activity relating to the trial and had no interaction with researchers as a result of being allocated to the control group (e.g. waiting list, no treatment, self-directed reading, or referral to community resources). This kind of comparator controls for minor non-specific effects, such as regression to the mean, the natural history of disease states and environmental factors common to all participants. It does not however, control for any non-specific effects that may be elicited by behaviour therapies.

The moderate face-validity controls use strategies:
Passive and structured. These involved some sort of regular and structured interaction with personnel associated with the experiment (e.g. regular lectures, specific reading, structured educational sessions on unrelated topics, regular blood pressure checks). This controls for the same confounders as Category 1 in addition to the effects of therapeutic contact and sense of active involvement.
• That were active in nature and generated some expectation of benefit but did not have effects or credibility as either a method of relaxation or meditation e.g. support groups, education about health factors measured in the study, or lectures on stress and lifestyle management. This controls for the same as Categories 2 and 3 in addition to the effects of social support, improved lifestyle, etc. Social support has been repeatedly demonstrated to be effective in improving mood and quality of life and reducing the severity of disease symptoms. “Standard treatment” was included in this category.

High face-validity controls use strategies that were:
• That were active in nature but not designed to generate significant expectation of therapeutic benefit (e.g. exercise). This controls for the same as Category 2 in addition to the effects of regular physical activity. Regular physical exercise has been shown to improve mood.
Active in nature, generated some expectation of benefit and elicited the simple physiological effects on rest but did not have specific credibility as a meditative method (e.g. progressive muscle relaxation, other relaxation methods, hypnosis, biofeedback, psychotherapy).
• The same as above but also had credibility as a meditative method (e.g. meditation techniques, strategies designed to convincingly mimic meditation) or constituted a legitimate form of psychotherapy (e.g. desensitisation, cognitive behaviour therapy, counselling).

Dr Ramesh Manocha