Defining complementary and alternative medicine : Revisiting the Debate and Plea for a Strategy Based on Plausible Effectiveness.

Discourse about Complementary and alternative medicine (CAM) is also controversial in several respects, including terminology. Understanding and using the term 'CAM' precisely remains necessary in some discussions. This article provides a contribution to a terminologically more reflected debate about CAM. Analytical methods are applied to analyse 'CAM' conceptually: reasons to define CAM are discussed, common definitions are critically analysed in light of argumentative plausibility, and typical conceptual needs in the debate about CAM are described. Based on this, an evidence definition of CAM is sketched. Complementary and alternative medicine is typically defined by positive attributes or (more usefully) by unconventionality. While the latter provides a viable definitional strategy, several questions remain regarding the logic and applicability. Attempts to improve CAM definitions should consider (a) presenting necessary and sufficient conditions, (b) separating 'complementary', 'alternative' and 'integrative', (c) understanding 'CAM' relative to specific diseases and (d) being explicit about possible changes of the CAM status. These requirements are used to develop a definition of CAM centring around the notion of probable specific effectiveness-a definitional strategy that might solve flaws in the current CAM discourse by spelling out some of the reasons why certain practices are not part of conventional treatment. The example of the cancer drug Imatinib serves to demonstrate the usefulness of focusing on plausibility of effectiveness instead of conventionality. Defining CAM in light of evidence properties might improve the debate. Independent of the terminological strategy pursued, articles and guidelines on CAM should at least reflect the implications and pros and cons of their own terminological decision. An evidence definition should be developed in detail.