“Living is easy with eyes closed …” on blinded RCTs and specific and non-specific effects of complex therapeutic interventions

IntroductionIt is assumed that, as measured during randomised placebo-controlled trials, specific and non-specific effects of an intervention do not interact with each other, and are simultaneously observable. It is argued this assumption means the results of RCTs (particularly for complex interventions, such as homoeopathy) are treated too simplistically.Purpose of studyTo examine if a complex intervention's specific effects and non-specific effects are complementary (in a sense derived and generalised from quantum theory), i.e., correlated sets of observables from an RCT, in which both are necessary to achieve a more complete understanding of the efficacy of an intervention.MethodsBuilding on earlier work, and based on the properties of Abelian and non-Abelian algebras, a mathematical argument is developed, which is used to examine the nature of the relationship between a complex intervention's specific effects and non-specific effects as observables from RCTs.ResultsThe mathematical argument suggests that it is essentially incorrect to assume specific effects and non-specific effects of a complex intervention (as measured during an RCT of a complex intervention) can be separated into simultaneously measurable, non-interacting sets of observables.ConclusionThis calls into question not only the legitimacy of conclusions drawn from RCTs, but also the blinded observational stance of the RCT protocol (which currently justifies - and is justified by - a reductionist approach to the efficacy of complex therapeutic interventions). Indeed, such RCTs might well be demonstrating a Heisenberg-type uncertainty between the specific effects of the intervention and the non-specific effects of the consultation, as complementary observable parts making up a whole irreducible phenomenon: the therapeutic process.