Reliable diagnoses are essential for guiding treatment recommendations, identifying prevalence rates for mental health service planning, identifying patient groups for clinical and basic research, and documenting important public health information such as mor— bidity and mortality rates. As the understanding of mental disorders and their treatments has evolved, medical, scientific, and clinical professionals have focused on the character- istics of specific disorders and their implications for treatment and research.
While DSM has been the cornerstone of substantial progress in reliability, it has been well recognized by both the American Psychiatric Association (APA) and the broad scientific com- munity working on mental disorders that past science was not mature enough to yield fully validated diagnoses—that is, to provide consistent, strong, and objective scientific validators of individual DSM disorders. The science of mental disorders continues to evolve. However, the last two decades since DSM-IV was released have seen real and durable progress in such areas as cognitive neuroscience, brain imaging, epidemiology, and genetics. The DSM-S Task
Force overseeing the new edition recognized that research advances will require careful, iter— ative changes if DSM is to maintain its place as the touchstone classification of mental disor— ders. Finding the right balance is critical. Speculative results do not belong in an official nosology, but at the same time, DSM must evolve in the context of other clinical research ini- tiatives in the field. One important aspect of this transition derives from the broad recognition observations. The results of numerous studies of comorbidity and disease transmission in farn— ilies, including twin studies and molecular genetic studies, make strong arguments for what many astute clinicians have long observed: the boundaries between many disorder "catego- ries" are more ﬂuid over the life course than DSM-IV recognized, and many symptoms as- signed to a single disorder may occur, at varying levels of severity, in many other disorders.
These findings mean that DSM, like other medical disease classifications, should accomo- date ways to introduce dimensional approaches to mental disorders, including dimensions that cut across current categories. Such an approach should permit a more accurate description of patient presentations and increase the validity of a diagnosis (i.e., the degree to which diag- nostic criteria reﬂect the comprehensive manifestation of an underlying psychopathological disorder). DSM—S is designed to better fill the need of clinicians, patients, families, and re- searchers for a clear and concise description of each mental disorder organized by explicit di— agnostic criteria, supplemented, when appropriate, by dimensional measures that cross diagnostic boundaries, and a brief digest of information about the diagnosis, risk factors, as- sociated features, research advances, and various expressions of the disorder.
Clinical training and experience are needed to use DSM for determining a diagnosis. The diagnostic criteria identify symptoms, behaviors, cognitive functions, personality traits, phys- ical signs, syndrome combinations, and durations that require clinical expertise to differenti- ate from normal life variation and transient responses to stress. To facilitate a thorough examination of the range of symptoms present, DSM can serve clinicians as a guide to identify the most prominent symptoms that should be assessed when diagnosing a disorder. Although some mental disorders may have well—defined boundaries around symptom clusters, scien- tific evidence now places many, if not most, disorders on a spectrum with closely related dis- orders that have shared symptoms, shared genetic and environmental risk factors, and possibly shared neural substrates (perhaps most strongly established for a subset of anxiety disorders by neuroimaging and animal models). In short, we have come to recognize that the boundaries between disorders are more porous than originally perceived.
Many health profession and educational groups have been involved in the development and testing of DSM-S, including physicians, psychologists, social workers, nurses, counselors, epidemiologists, statisticians, neuroscientists, and neuropsychologists. Finally, patients, fam- ilies, lawyers, consumer organizations, and advocacy groups have all participated in revising
DSM-5 by providing feedback on the mental disorders described in this volume. Their moni- toring of the descriptions and explanatory text is essential to improve understanding, reduce stigma, and advance the treatment and eventual cures for these conditions.