Mixed anxiety and depression: from theory to practice.

The 10th International Classification of Disease (ICD-10) introduced the concept of mixed anxiety-depression to define patients presenting both anxiety and depressive symptoms of limited number and/or intensity, not sufficiently severe to fulfill criteria for a specific diagnosis of depressive or anxiety disorder. Epidemiologic surveys have shown that these patients may display significant levels of functional impairment, have unexplained somatic symptoms and a high use of nonpsychiatric medical care, have long-lasting symptoms, and are at risk for more severe psychiatric disorders. A DSM-IV field trial concluded that patients with affective-symptoms not meeting thresholds for DSM-III-R disorders were at least as common as patients with anxiety or mood disorders, and that their symptoms were associated with significant distress or impairment. Although some of these patients present residual symptoms from previous psychiatric episodes and may request treatment specific to these conditions, it is not known if those without a psychiatric history could benefit from pharmacologic or psychological treatments usually used in mild outpatient cases.