An extensive search of the scientific literature identified 3,500 peer-reviewed publications that featured “meditation” as a key word. Yet, of these, only 135 (approximately 4%) fulfilled the very basic requirements of experimental evaluation, i.e. they were prospective trials using control groups and random allocation. Importantly, even within this subset of more rigorous studies, there is no convincing evidence that meditation has a specific effect. In fact within this set of randomised controlled trials (RCTs), there appeared to be an inverse relationship between methodological rigour and likelihood of an outcome that is favourable to meditation.
Dr Ramesh Manocha
Researching meditation poses a unique challenge, since participants receiving the “inert” (or “placebo”) treatment must be involved in a placebo-like activity that nevertheless requires their active, conscious and conscientious involvement. They must also be sufficiently convinced of its authenticity to motivate them to participate at a level necessary to maintain the validity of the study.
More information about placebos can be found at Dr Manocha’s blog.
The design of RCTs for meditation (or any behaviour-based therapy for that matter) involves a number of unique challenges compared with pharmacological trials. While both categories of trial use an inactive placebo, the pharmaceutical trial uses an inert “sugar tablet” which appears similar to the medication being administered. The participant taking the “sugar tablet” is unable to ascertain whether or not they are taking the active or placebo treatment thus allowing the trial to control for confounding factors that may contribute to changes in the participants condition other than that caused by the treatment being studied.
More information about the use of placebos in meditation research can be found at Dr Manocha’s website.
The mechanisms by which sahaja yoga meditation (SYM), or in fact any meditation technique, exerts its claimed effects are unclear. One very popular view, which has become more or less the default explanation of meditation effects is in terms of the physiological changes that characterise the Relaxation Response — that is, reductions in heart rate, blood pressure and respiratory rate and increases in skin temperature, skin resistance and alpha wave activity in the brain. All of these are brought about by reducing activity of the sympathetic component of the autonomic nervous system (ANS) and increasing activity of the parasympathetic components of the ANS. Psychophysiological studies in India certainly appear to confirm that SYM does reduce many parameters of sympathetic activation.
“More recently scholars have proposed that since Mindfulness and similar styles of meditation necessarily allow participants to become “more aware of thoughts and feelings and to change their relationship to them”, therefore somehow “that greater awareness will provide more veridical perception, reduced negative affect and improve vitality and coping”. Then it seems logical that by completely eliminating background mental noise, the meditator would necessarily increase internal and external awareness, possibly to a greater degree than in Mindfulness. Perhaps SYM acts via both the autonomic and cognitive pathways. Aftanas’ brain studies of SYM meditators also suggest that the effect of SYM on the central nervous system may also offer some explanation.
Dr Ramesh Manocha.
Dr Ramesh Manocha explains why strong controls are necessary when researching the real-world relevance of meditation in this excerpt from his thesis:
“Some might argue that controlling for non-specific effects is an academic exercise with little real-world relevance. This is supposedly because factors such as the placebo effect, expectancy of relief and demand characteristics are a critical component of most health interventions when administered to patients in the field. Thus trials directed at assessing the ecological (“real-world”) relevance and validity of an intervention have no need to control for factors which will be operating in conjunction with the intervention effect anyway. Authors of such reports add that studies with these kinds of controls reflect real-world scenarios since study participants offered either meditation or the “usual care” (i.e. usually nothing) reflect the reality of their environment. This line of argument assumes that the only value of proper controls is its ability to help answer theoretical questions about meditation, but that such controls fail to allow meditation to demonstrate its “practical relevance”.
“Yet commercial purveyors of meditation frequently claim that their often expensive proprietary techniques are uniquely effective in order to justify expensive fees. Moreover, many meditation techniques can be arduous and culturally challenging. It is important to determine whether it is justifiable to demand these significant costs and efforts or whether the same effects might be elicited by simpler strategies that are similarly rich in non-specific effects but possibly cheaper and easier to implement. By controlling for non-specific effects, it is possible not only to provide important theoretical information about whether meditation has any unique effects, but also whether it is an economically justifiable option, whether it offers any more of an advantage over accepted strategies and whether the claims of meditation enthusiasts have any basis.”
More information about Dr Manocha’s research can be found at his website.