The double-blind in danger: untoward consequences of informed consent

Patients and physicians correctly identified medication assignments in 70% of the cases in a double-blind trial of an appetite suppressant. The breach of the double-blind design may have had therapeutic consequences; correct identification was associated with favorable outcome. These findings suggest that requirements for describing the side effects of medications to patients before they give informed consent may help them guess which medication they receive and thus may influence the integrity of double-blind studies and the results of controLled trials.