The need for evidence-based research ethics: a review of the substance abuse literature.

Participants in substance abuse research may be vulnerable for multiple reasons. International research ethics guidelines and policy statements require that researchers provide extra protections when conducting research with vulnerable subjects, but it is uncertain which measures best protect vulnerable individuals. Concerns about vulnerability have been translated into only the vaguest regulatory requirements, and very little empirical data exist to guide researchers and ethics review committee members who want to protect participants. This article reviews two bodies of substance abuse research ethics literature. First, "normative" articles, that is, articles that discuss ethical issues that may arise in substance abuse research, are discussed. The resulting taxonomy of ethical issues then guides a review of empirical studies on issues like the informed consent process and the use of financial incentives in substance abuse research. While the ethical issues in substance abuse research are numerous and well-documented, the evidentiary base for addressing these issues is inadequate. If any one major theme emerged from the existing studies, it is that many well-intentioned, protectionist concerns--about recruitment incentives, consent comprehension, and drug administration studies--are not supported by empirical data. While these findings are at best tentative, they suggest how research on research ethics might ultimately benefit participants.