[Comorbidity of anxiety-depression and its treatment]

The comorbidity of anxiety/depression, or the co-occurrence of anxious and depressive symptoms is an heterogenous concept. There is comorbidity when a whole anxious syndrome and a whole depressive syndrome last during a period of life. The association of minor anxious and depressive disorders in a same patient during a certain period of time is the definition of mixed anxious and depressive disorder. The comorbidity of generalized anxiety disorder and dysthymia is more frequent than each of these two disorders separately considered. The interpretation of comorbidity needs cautiousness. The results are very different if one considers only the actual disorders or the occurrence on the whole period of life. The longitudinal epidemiological studies as the ones made by Angst and by Wittchen demonstrate that most of the patients with an anxious disorder become depressive. A third of these patients are cured and one third to one quarter of them evaluate toward chronicisation. There are many common features between the chronic depressions, the classical neurotic depression and the general neurotic syndrome defined by Tyrer. If the presence of minor mixed symptoms, anxious and depressive, is a clinical reality, to isolate a "anxiodepressive" syndrome may lead to create a miscellaneous category, which could cause an excess of drug prescription. The reactivity of mixed syndromes, anxious and depressive, seems distinct from the one of anxious disorders and of pure depressive syndromes.