Yoga: Some Unanswered Questions

Grover et al (1994) have provided an excellent and thought provoking analysis of the usefulness of yoga in treating neurotic disorders. Some questions however remain. One criticism of psychotherapy is that the criteria for the selection of suitable candidates usually identify patients with good prognostic features-patients who may improve even without any therapeutic intervention. Another criticism that nonspecific factors , unrelated to the principles invoked by the form of psychotherapy used, may be involved in the mediation of benefit (Bloch, 1982). Are there parallels with studies on yoga and mental health? Since the practice of yoga requires a form of discipline, it is possible that only individuals capable of such discipline will be recruited, or will provide informed consent for participating in yoga research, or will comply with the study protocol. Thus, a selection filter may bias the research outcome. It is also possible that only individuals capable of such discipline will be found in the study to benefit from yoga as a means to mental health. Since most schools of psychotherapy invoke some form of psychological discipline, nonspecific factors may play a role in improvement with yoga. Here, the nonspecific factor is the capacity for and the utilization of psychological discipline. Discipline is just one example of a selection filter, or of a nonspecific factor in the mediation of improvement with yoga. Belief in yoga as a viable therapy is a second possible example. Capacity for relaxation is a third. Further examples are no less difficult to find. Therefore, randomized, controlled studies on yoga should provide data not only on the subjects included in the study but also on the subjects who were found unsuitable and the subjects who did not provide consent for participation. These data are important because research usually seeks to generalize to the population the findings from the sample. Generalization is possible only if the sample is representative of the population. Studies on yoga should also provide details of patients' behavioral profiles and belief systems insofar as such parameters may comprise either selection filters or nonspecific elements invoked in the therapeutic processes. The serious questions that I believe remain un-answered are: Is outcome research biased in favor of yoga by filtering processes during the selection of patients, provision of informed consent, compliance with treatment, etc? Are patients who benefit from yoga those who, by virtue of good prognostic features , would have improved even without …