This chapter examines how clinical investigators ensure the safety of psychiatric research participants while maintaining the integrity of research protocols. It discusses the ethical issues arising from data monitoring, disclosure of interim data, and termination of clinical trials. It outlines unique features of psychiatric research and related cultural issues that may warrant consideration before and during clinical trials. It focuses on the Data Safety Monitoring Boards (DSMBs) overseeing clinical trials their development of detailed plans for monitoring safety and protocol adherence. It looks at the use of statistical programs by DSMBs to document the progression of research studies and make early termination decisions; whether DSMBs actually improve the safety of participants or the integrity of research; how independent DSMBs are; and the factors that DSMBs consider when terminating a trial. Cultural issues involved in clinical trials and challenges that may compromise the neutrality and function of DSMBs are analyzed.