Classifying Insomnia in a Clinically Useful Way

Insomnia is a prevalent complaint that may arise from myriad causes. Therefore, patients whopresent for insomnia evaluation and treatment represent a rather heterogeneous group that merits areliable and valid diagnostic system. This review article considers the general purposes of diagnosticclassification per se and highlights the factors that influence the development of diagnostic nosologies.Various past and current insomnia nosologies are described, and data supporting the reliability,validity, and general utility of these systems are presented. In addition, the limitations of existing nosologiesare discussed, and factors that will lead to improved insomnia nosologies in the future areconsidered. The panel discussion that follows this review highlights the limitations of current nosologiesand notes barriers that must be overcome to improve upon the currently available classificationsystems.