Generally a medicine or a drug is studied against two groups of people. one group taking medicine and one that is not taking. even though it is randomised controlled study we need to remember that the drug efficiency is being tested and evaluated with a group of people who are doing nothing – means they are not following any will defined lifestyle practices like exercising or eating healthy food or taking care of there stress and sleeping patterns or taking some supplementation.
So now you are testing something (the power of drup) against nothing (sugar pill). General speaking when you are doing an intervention by using a chemical which blocks certain signals that are causing pain or trauma, then obviously it is going to work in some people. When you are comparing this group of people with a group of people who are doing nothing and taking a fake pill, then the results would be by asked towards the people taking the drug.
*Do read the Disclaimer