Research in child, adolescent, and developmental psychopathology continues to flourish, even more so than when the first edition of this text was published. Previously recognized disorders are even better delineated than they were only a few years ago, and a few new ones seem to have been discovered along the way. The publication rate in this field is extraordinary, with many journals now focusing exclusively on childhood mental illness and health, and numerous articles on children appearing each month in journals that were once the exclusive domains of adult psychopathology. To those of us who take a developmental view of psychopathology, this is a most gratifying state of affairs as we come to recognize the roots of many adult disorders in childhood and adolescence. The down side, of course, is that even the expert researchers in the various disorders that constitute this field find it harder than ever to keep abreast of research findings appearing at such a rapid clip. And woe to the clinical professionals who must deal with these childhood disorders: They may find themselves quickly and hopelessly behind in the advancements occurring in the understanding of these clinical conditions. Hence the need for a volume such as this, and especially for its second edition, to assist the clinical professional, student, and even expert in remaining current on child and adolescent psychopathological disorders.
Now more than ever, the field of child psychopathology epitomizes the dynamic, accumulative, and self-correcting nature of the scientific enterprise, as new findings expand upon and are assimilated with the established facts in any given disorder. Often these new findings challenge older theoretical or conceptual assumptions or more explicit models of these disorders, at times even leading to small-scale paradigm shifts in perspective. In short, the literature on child and adolescent psychopathology is alive, well, prosperous, and rapidly advancing. Old questions undoubtedly get answered, but along the way those answers raise new questions for researchers to pursue in ever more complex programs of research on each of the childhood disorders covered here. Although the pace and excitement levels vary considerably across different areas of child psychopathology, within each area the eager anticipation of new knowledge remains palpable as new lines of research and methodologies—such as neuroimaging, behavioral and