Panel discussion: changing how we think about insomnia.

44 J Clin Psychiatry 2004;65 (suppl 8) Current Insomnia Classification Systems After presenting a general definition of diagnostic classification and the factors that influence the development of classifications, Edinger discussed past and present insomnia nosologies and the data supporting the reliability, validity, and general utility of these systems. In the subsequent panel discussion, panel members agreed that a successful nosology would include several important characteristics. A valid diagnostic system would be predictive of both pathophysiology and therapeutic approach; in other words, assigning the proper diagnosis to patients and providing the recommended treatment for their insomnia subtype would consistently result in symptomatic amelioration. To enhance reliability and aid research, a successful nosologic system should also provide clear definitions and criteria of diagnostic categories. To address clinical needs, it should define these diagnostic criteria, which point to therapeutic options and long-term morbidity, by fitting the empirical profiles seen in clinical practice. However, sleep medicine currently faces a chicken-and-egg conundrum with regard to nosology development: a main reason to develop a classification system is to direct therapy, but in the absence of reliable therapies for many of the insomnia subtypes, it is difficult to develop an evidence-based nosology. The panel discussed a number of factors contributing to the present dilemma. First, panel members agreed that, at present, there is no consensus on how to classify or characterize the various clinical presentations of insomnia, nor is there a set of widely accepted treatment guidelines that can be used as a “gold standard.” In other words, there are no studies demonstrating the absolute superiority of a particular treatment for any particular diagnostic group. This is a major obstacle to the construction of a classification system. Second, exacerbating the problem of successful treatment is the heterogeneity of patient populations. The results of different studies cannot be legitimately grouped to contribute to clinical consensus building because the insomnia disorders under investigation are not consistently defined. Another contributing factor is the lack of diagnosPanel Discussion