The last Diagnostic and Statistical Manual (DSM): replacing our symptom-based diagnoses with a brain circuit-based classification of mental illnesses.

With the recent publication of the DSM 5 (Diagnostic and Statistical Manual of the American Psychiatric Association, 5th edition), a fresh round of criticism of this nomenclature and of psychiatric disorders in general comes forth, as it does every time a new edition is published. This criticism ranges from ‘‘disease mongering’’ and inventing new illnesses while pathologizing normal behavior (especially in children), to conflicts of interest and the notion that the DSM is a political or commercial but not a scientific document. Although many criticisms have merit, the field of mental health is better off having a common vocabulary with reliable descriptions of psychiatric syndromes than to have a nosologic free-for-all by every mental health professional’s idiosyncratic use of terms. Unlike previous editions, with the publication of DSM 5, there may never be a DSM 6, since this document will not stay on the shelf until another revision is undertaken in another 30 years, but is foreseen as a living document with frequent iterative updates. The vision for where this is headed is foreshadowed by the RDoC project, where psychiatric symptoms are linked both downstream to brain circuits and the molecules, genes, and neurobiology that regulate them, as well as upstream to diseases with shared pathophysiologies, and treatment responses rather than to syndromes with shared symptom clusters (Figure 1). That is, we are aiming to go from categorical to dimensional (Figure 2). The current DSM is categorical (down/vertical arrows in Figure 2); i.e., it clusters together symptoms