The diagnostic validity of anxiety disorders and their relationship to depressive illness.

Several serious questions exist regarding the diagnostic classification of anxiety disorders. The authors examine the diagnostic validity of generalized anxiety disorder and panic disorder and explore their relationship to major depression, critically reviewing relevant descriptive, lifetime occurrence, family and genetic, drug treatment, and neurobiological studies. There is strong support for the diagnostic validity of panic disorder, but few data are found to support a separate diagnostic classification of generalized anxiety disorder. In addition, several lines of evidence suggest that a common vulnerability may exist for some forms of panic disorder and major depression. The implications of these findings for diagnostic application, treatment, and future research are discussed.