To the Editor: Ellen Leibenluft, M.D., et al. (1) presented an informative and useful realignment of the nosology for juvenile mania. The authors considered an array of important "methodological and conceptual issues" in their analysis, but they did not clearly distinguish between the methodological and the conceptual. That is, to what extent do the authors put forth the new categorization on the basis of the difficulties in assessment of DSM criteria in the context of the juvenile population? Or do they believe that there is a fundamental distinction among the categories they propose? If the latter, to what extent is the conceptual distinction limited to the juvenile population, or should it be applied or adapted for adults as well?