Mental silence and its associated yogic philosophy may provide a basis for taxonomy of meditation that is practically useful in the delivery of healthcare. An intervention with a specific effect such as Sahaja Yoga meditation has a wide range of applications in medicine, psychology and neuroscience. It is particularly relevant to the growing field of Complementary and Alternative Medicine (CAM) since meditation represents an important genre of CAM modalities and the apparent therapeutic effects of mental silence that are apparent in this thesis now position this genre of CAMs in a higher category of practical importance to healthcare.

Dr Ramesh Manocha

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Like any other evaluation of therapeutics, the detectable effect of the intervention will be determined by the degree to which the participant complies with the treatment. This is particularly important in meditation research because meditation requires considerable active involvement and commitment. There are several ways to assess compliance, including attendance rates at supervised treatment sessions, home-practice diaries and subjective experience reports.

Dr Ramesh Manocha

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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

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For my systematic analysis of meditation studies, because of the relatively small number of studies available for analysis, the many different meditation techniques were grouped into 5 thematically related categories. These were:

  1. Relaxation Response and studies describing the intervention as based on it.
  2. The MBSR and studies describing the intervention as based on it.
  3. TM and studies describing the intervention as based on it.
  4. Multimodal interventions of which meditation is one part, such as yoga, lifestyle strategies etc.
  5. Miscellaneous, where only a few studies had been conducted on a particular technique and/or when a technique did not easily fall into one of the previous categories.

Dr Ramesh Manocha

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With regard to the physiology of meditation, research designs can be divided into 3 categories:

1) Case studies of meditation featuring small numbers of participants in which there is no attempt to control for confounding variables. While these are useful for generating hypotheses, they do not provide scientifically valid insights into meditation’s purportedly unique effects.

2) Own-control studies use participants in time sequential series (ie ab, aba or similar designs) in which the “a” condition is pre-meditation or non-meditation and the “b” condition is meditation. The “a” and “b” conditions are then compared. These studies have generally demonstrated significant differences (interpreted to be in favour of meditation) but they suffer from substantial limitations because they compare meditation to non-meditation and then assume that any differences are due to meditation, whereas they may in fact be due to methodological factors not specific to meditation at all (such as rest, expectancy, researcher demand and environmental issues). Further, this design is vulnerable to the possibility that one condition might be contaminated by carry-over effects from the preceding condition. A further important consideration applies especially to the case of novices — if the meditator is not sufficiently skilled then they may have difficulty in generating physiological changes and the effects (although potentially real) may not become detectable.

3) Experimental control studies are much more reliable as they involve two independent groups in which one meditates and the other engages in a control activity such as rest. There are however, methodological difficulties associated with this approach as well. First, use of novices (who are introduced to meditation during the trial) may mean that the effects of meditation are not large enough to generate a detectable change. Second, while use of advanced meditators (those who have practiced meditation over many years) may ensure that the necessary magnitude of effect is achieved, the question of selection bias becomes a significant consideration.

An ideal strategy would involve an experiment in which participants are randomly assigned from the same sample to either a meditation or a control group. This approach is rarely feasible however, since it would conventionally require many months or even years of practice before the participants achieved competence. With such lengthy time-lines the accumulation of drop-outs may in any case lead to selection bias. Therefore, a reasonable compromise strategy might involve using experienced meditators and comparing them to non-meditators who have either been matched for parameters including interest in meditation, or have been randomly selected from the population. This latter design was selected for the study described in this chapter.

Dr Ramesh Manocha

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The effects of meditation on anxiety and stress are comparable to effect sizes described in conventional meta-analyses of psychotherapy field studies. For example Mattick’s (1990) review of psychotherapy for neurotic patients reported a mean effect size of 0.74 for verbal psychotherapy and 0.97 for behavioural psychotherapy vis-a-vis a mean effect size of 0.55 for placebo. My review of meditation on the other hand found a mean effect size of 0.90. It should be noted however that the meditation studies focused on participants with non-pathological anxiety states, raising the possibility that the potential impact of meditation may be limited by a “ceiling effect” due the recruited sample’s relatively mild symptomatology and hence minimal scope for clinical improvement.

Dr Ramesh Manocha

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Meditation studies published on medline

This graph shows the number of meditation studies considered as serious explorations of meditation’s effects published per year in the MEDLINE database.

The maximum yearly output was in 2000–2001 when 12 RCTs were reported in MEDLINE. In the same time period 106 RCTs for fluoxetine, as an example of a mainstream medication, and 98 RCTs for acupuncture, as an example of a complementary medicine, were published. The rate of publication of RCTs on meditation is poor in comparison to other therapeutic modalities in either the mental health or complementary and alternative medicine genres.

Dr Ramesh Manocha

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The Jadad scoring system is a widely used method of rating randomised controlled trials for basic methodological rigour. The Jadad system is inadequately structured to meaningfully discern the methodological standards of meditation trials. This is because the unique issues associated with controlling for non-specific effects and sources of bias are not adequately represented in this system.

Dr Ramesh Manocha

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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

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Methodological validity is therefore the major challenge to meditation research, and the chief problems within this broad category are first, the use of appropriate control strategies, second, the need for randomisation and other strategies to exclude bias and third, a definition of meditation that allows inter-trial comparability and remains consistent with the traditional ideas of meditation as a state of non-thought.

Plausible controls
Plausible control groups are critical in behaviour therapy research because of the need to exclude the significant confounding effects of non-specific factors (such as placebo, therapeutic contact and researcher expectancy). The significance of this issue is borne out by the fact that even comparative trials of behaviour therapies often end up demonstrating equivalence of effect255. Such non-specific factors are also significant in meditation research. Expectancy alone, for instance, has been shown in a number of studies to positively influence the apparent effect of meditation4.
The essential criteria for a control strategy in meditation trials should therefore be first, convincing plausibility as an active intervention in its own right and second, a process that involves relaxation and reduction of somatic arousal (since this is the nearest conventionally understood phenomenon that resembles meditation).

Randomisation and other strategies to exclude bias

There are a large number of controlled meditation trials using dissimilar cohorts in non-randomised trials. The need for randomisation to exclude selection bias is obvious, yet as previously pointed out, less than 4% of the total number of peer-reviewed publications used random allocation of participants.

Dr Ramesh Manocha

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