This paper considers the proposed revisions to the DSM revision 5. The article discusses the process of classification in general and its application to the DSM. The argument in part is that classification schemes are judged by their usefulness in advancing social practices. The DSM serves a number of different such practices—most obviously research and treatment—and these may make different demands on any scheme. The paper goes on to consider the ethical issues involved in classifying mental disorders and in changing existing classifications. A preliminary scheme of ethical issues in relation to false negatives, false positives and social issues is offered. Finally, the paper considers the wider implications of the proposed changes to the classification of personality disorders and whether these changes may have a ripple effect on our understanding of ourselves and others. Copyright © 2011 John Wiley & Sons, Ltd.