What Is Causing the Reduced Drug-Placebo Difference in Recent Schizophrenia Clinical Trials and What Can be Done About It?

ology and the International Society for CNS Drug Develop-ment was held in Brussels, Belgium. Both groups, with membership from industry, academia, and governmental and nongovernmental agencies, have been formed to address scientific, clinical, regulatory, and methodological challenges in the development of central nervous system therapeutic agents. The focus of this joint session was the apparent dim-inutionofdrug-placebodifferences inrecentmulticentertrials ofantipsychoticmedicationsforschizophrenia.Tocharacter-ize the nature of the problem, some presenters reported data from several recent trials that indicated higher rates of pla-cebo response and lower rates of drug response (even to pre-viously established, comparator drugs), when compared with earlier trials. As a means to identify the possible causes of the problem, discussions covered a range of methodological fac