It seems obvious that the non-specific effect of any intervention is closely related to its credibility and plausibility as a therapeutic intervention i.e. its “face validity”. Now, some of the effects associated with meditation must be non-specific, i.e. comprising a mixture of placebo, therapeutic contact, spontaneous improvement, and so on, whereas some, hopefully, are specific to meditation alone. One might even propose that different meditation techniques have varying proportions of specific and non-specific effects. Within the context of an RCT, the control strategy should ideally:

• elicit all the non-specific effects that meditation might have, but have none of meditation’s specific effects;
• not have any specific effects of its own.

By fulfilling these criteria the control strategy makes the RCT methodology sensitive to any specific effects of meditation that might be detectable.

Dr Ramesh Manocha