From another article:

Finding genetic markers for the placebo effect could raise ethical questions about how companies design their clinical trials, Furmark says. For example, "it could be tempting to screen all individuals and ... select only those with [the] nonresponsive phenotype [for the trial]."

Why is that an ethical question? It would be wonderful if one could exclude those that might exhibit a strong placebo effect from the trial. How is that possibly unethical?

http://sciencenow.sciencemag.org/cgi...ll/2008/1202/1