While the randomised controlled trial (RCT) is a valuable scientific tool, its parameters need to be defined if it is to produce scientifically valid results. In the case of trials of homeopathic treatment, if the following points are not taken into account, the results in the verum arm will tend towards those in the placebo arm, and the trials will produce ambiguous, contradictory or statistically insignificant results.
What is being treated: Homeopathy defines what is being treated as the totality of the individual's symptoms. Orthodox medicine uses generalised categories of diseases. Failure to use the homeopathic definition would mean that successes in the verum arm of the trial would only occur in those cases where the two definitions effectively overlapped.
Relationship to the medical history: Homeopathy treats symptoms as part of a process, recognised formally in Hering’s ‘law of cure’. As a result what can be treated depends on the individual’s medical history, not on an abstract ‘intention to treat’. Failure to match the ‘intention to treat’ to the requirements of the ‘law of cure’ would mean that successes in the verum arm of the trial would only occur in those cases where the two requirements effectively overlapped.
The criteria for selecting patients: The likelihood of successful treatment increases with the individuality of the patient’s symptoms, but this individuality can be reduced as a result of factors, such as the previous or concommittent use of prescription and non-prescription drugs or the presence of serious pathology. Failure to take these factors into account will affect the potential for successful treatment in the verum arm of the trial.
What constitutes success: The success of homeopathy as a therapy in an individual case may not initially mean improvement in previously selected symptoms. There may be one of a range of reactions reflecting the state of health of the patient, and success as part of the process of recovery may involve a change in symptoms, rather than a simple reduction in some symptoms. Failure to use the homeopathic definition of improvement would mean that successes in the verum arm of the trial would only occur in those cases where the homeopathic and trial definitions effectively overlapped.
Scale of improvement: What constitutes significant improvement depends on the individual case, and particularly on the medical history and circumstances of the patient. Selection of a standard of improvement which does not reflect these variations would mean that successes in the verum arm of the trial would only occur in those cases where the homeopathic and trial definitions effectively overlapped.
Time-scale: The rate of any improvement in a particular case will vary according to the medical history of the patient and factors such as stress and current or previous use of some prescription or non-prescription drugs. Selection of a time-scale which does not reflect these variations would mean that successes in the verum arm of the trial would only occur in those cases where the time-scale happened to be appropriate.
Issues affecting the course of treatment: Concomitant drug therapy, emotional shocks (both positive and negative), accidents and other factors could affect the course of treatment by delaying or altering the sequence of recovery. Failure to take these into account could affect the results of the verum arm of the trial.
The range of remedies or potencies: For homeopathic treatment to be successful more than one remedy and potency may be required over the period of the trial. Restriction of a trial to the use of a single remedy and potency would mean that successes in the verum arm of the trial would only occur in those cases where the homeopathic and trial requirements effectively overlapped.
Standard of practice: Homeopathy involves a continuous process of decision-making about the remedy to be prescribed, so trial protocols need to establish criteria for a minimum level of competence. Failure to take practitioner competence into account could lead to unrecognised distortions in the results of the verum arm of the trial.
Lack of response: A failure to see any response to the prescription affects the conduct of treatment. In particular the remedy or potency is likely to be changed by the practitioner in order to correct what they will perceive as a mistake in the remedy selection. In a trial context repeated failure would tend to lead a practitioner in either arm of the trial to assume that they are part of the placebo arm. Where the practitioner is in fact in the verum arm, they will be acting on a mistaken assumption and failing to treat the information of non-reaction as important data. Failure to manage this issue appropriately would affect the conduct of the placebo arm of the trial, and could affect the results of the verum arm.
Drop-out rates: In some cases treatment may require a time-scale incompatible with maintaining a placebo arm of the trial (a problem which inhibits any long-term trial). As a result a trial would either have to include only cases manageable within a short time-scale, in which case researchers would need to establish criteria for identifying such cases, or there would need to be criteria for handling possible high levels of drop-outs in the placebo arm so as not to invalidate the trial.
Why it works
What factors affect RCTs of homeopathy?