Foundations of the new nosology.

DSM-III and its revisions have provided little in the way of explicit historical or philosophical foundations. The logical empiricism embedded in its operational criteria and its external approach to validation are inadequate to account for the presumption of nosological regularities or the specific categories endorsed by the taxonomy. The nosologic operation that Jaspers referred to as the "synthesis of disease entities" is explored in connection with the central distinction in DSM-IV between mood disorders and schizophrenic disorders. This synthetic operation is analyzed in terms of the paradigmatic shift from the mania-melancholia matrix of pre-modern psychiatry to the manic-depression/dementia praecox model defined by the work of Kraepelin. In the context of this analysis the self-evidence of these regularities is questioned.