Mixed anxiety-depression and its implications for models of mood and anxiety disorders.

Recent findings have suggested that there is a distinct group of patients presenting with subthreshold levels of mixed anxious and depressive symptoms associated with significant functional impairment. Accumulating evidence of this type ultimately led to a multisite field trial which investigated the possibility of developing a new category of mixed anxiety-depression (MAD) for the DSM-IV. The field trial confirmed both the existence and impairment of a sizable group of patients with mixed subclinical anxious and depressive symptoms, and provisional criteria for MAD were proposed. Although the validity of the tentative MAD category has yet to be established, the unique characteristics of patients presenting with MAD symptoms have important implications for models of mood and anxiety disorders. We argue that the particular pattern of impairment associated with MAD provides additional evidence that anxiety and depressive disorders have a shared diathesis best captured by the construct of nonspecific negative affect.