The key lesson of the past decade of clinical trials is the heterogeneity of psychiatric diagnoses. Diagnostic categories, such as schizophrenia, depression, or autism, though each defined by a broader set of observed symptoms, may individually comprise different biological entities with distinct pathophysiologies, requiring different treatments. What we need now are medications for targeted subgroups of patients within diagnostic categories who share biology, not just symptoms. This is the essence of personalized medicine or what has recently been called “precision medicine” [Committee on a Framework for Developing a New Taxonomy of Disease, 2011]. Personalized medicine overlaps [Fig. 1] with what is coming to be known as “genomic medicine,” which uses information from a patient’s genome for diagnosis, prognosis, and treatment planning, emphasizing uncommon or unique aspects of each patient [for review, see Feero et al 2010]. Emphasis on the unique aspects of a patient is, in fact, nothing new for psychiatry. Effective psychiatric care has always been challenging, in part, precisely because it has always been personalized. Every unhappy family may indeed be unhappy in its own way. That is why we need a much larger variety of treatments, each with a much narrower range of indications.
