The article states that people drop out due to side effects even on Placebo. This could be to additives in the placebo capsules. They must put something in the capsule even if it is ot the drug.
I have had so much experience having reactions to various drugs that I am rarely susceptible to imagination about what they are doing to me. Sometimes I've had a predicted possible reaction, but just as often I've had an unusual reaction, such as slow pulse with chemo I was taking last year. I have been trained by a lifetime of vigilance to notice what is happening and also notice what is not happening.