Personalized treatment is based on knowledge of an individual's genetic, physiologic, or behavioral characteristics that is precise enough to predict his or her response and guide treatment matching. A preemptive treatment arrests a disease process before it occurs or sufficiently early in its course to prevent devastating effects. Yet among the thousands of applications that NIMH receives each year, the report notes, very few propose development of personalized or preemptive treatments. The pathway to the discovery of such treatments, which are already used in oncology and cardiology, is not as clearly marked in psychiatry. Psychiatric genetics has not yielded a single validated target for any mental disorder, the report notes, and virtually all drugs approved for mental disorders have been incrementally changed versions—"me too" drugs—of compounds that have been available for the past 40 years. Preemption requires a basic understanding of a disease process, but the causes of mental disorders and their mechanisms are unknown. In addition, mental disorders are increasingly considered developmental brain disorders. By the time a diagnosis is made, causal factors may no longer be evident. In psychiatry, unlike oncology, diseased tissue cannot be removed for analysis and treatment development.