Monday, January 07, 2019

Placebo Effect, Honest Placebo, Open-label Placebo

In a previous post, I discussed the Placebo Effect and The Choice of Placebo. When a placebo-control trial failed, we would try to understand if it was because the experimental drug had no significant effect or because the placebo treatment had an effect. There could be multiple reasons for a placebo-controlled trial to fail even though the experimental drug was actually effective.

Recently, I read some articles about the placebo effect and people claimed that placebo did work. 

I believe that the placebo may have some effects, but only in diseases in the CNS and psychological area or in diseases with subjective symptom measures. I also think that the placebo will have an effect only if the patients who receive the placebo treatment do not know which treatment they are receiving (i.e., blinded).

A concept of ‘honest placebo’ blows my mind. The term ‘honest placebo’ is used to describe the open-label placebo – the patient knowingly taking the placebo. When we do placebo-controlled studies, we have always tried to conceal the placebo (through blinding) to avoid the potential biases. In studies with open-label placebo, the blinding is no longer necessary.

The prominent researcher in the area of the placebo effect is Dr. Ted Kaptchuk in Havard University, See Ted Kaptchuk’s TEDMED and his talk Placebo effects make good medicine betterIt seems to be boring if someone spends all of his / her efforts to study the placebo effect. You would think that it will be difficult to get the funding to study the placebo effect. However, Dr. Ted Kaptchuk did receive the NIH grants for studying the placebo effect (for example his NIH grant Enhancing the Placebo Effect in Irritable Bowel Syndrome).

In assessing the placebo effect, the following needs to be considered:
  • Quantifying the percentage of subjects with the placebo effect
  • Don’t expect the placebo effect in diseases beyond certain disease areas (such as CNS, psychological,…). Don’t expect the placebo effect in cancers.
  • Using the objective measure to determine if the placebo effects by subjective measures are real
  • Considering the composition of the placebo treatment. See a previous post Placebo Effect and The Choice of Placebo
  • Considering the treatment compliance (in both the experimental group and the placebo group)
  • Considering the course of the disease (some disease symptoms have a pattern of fluctuation, relapse-remission pattern. 
  • checking if the placebo effect is triggered by the concomitant medications or concurrent treatments (that the researchers may not be aware of).