The drug-placebo response curve: a new method for assessing drug effects in clinical trials

Unlike many other areas of medicine, psychiatric clinical trials have no gold standard laboratory tests with which to measure drug effects. Although reliable and valid psychometric measures are available, the standard analysis of such measures obscures the clinical relevance of drug effects. In this study, the authors sought to address this problem by developing a graphical display called the drug-placebo response curve. The features of the drug-placebo response curve are described by applying it to a previously published, controlled clinical trial of desipramine in the treatment of adults with attention-deficit/hyperactivity disorder. Unlike the standard analysis, the drug-placebo response curve showed that desipramine was effective over the full range of response and that it prevented worsening, in addition to increasing the likelihood of improvement. The drug-placebo response curve provides clinically relevant information about the effect of drugs on continuous outcomes in controlled clinical trials.