Abstract
Mood and anxiety disorders are the most prevalent psychiatric disorders and the their symptoms also frequently co-occur. In the present thesis, the implications of this so called comorbitidy of mood and anxiety disorders for the accuracy of psychiatric diagnosis and the implications of such comorbidity for treatment with antidepressants has been explored. The past three decades have witnessed considerable progress in the pharmacological treatment of mood disorders. The efficacy of antidepressants has not been restricted to mood disorders, however. Patients with anxiety disorders also appear to benefit from treatment with antidepressants. Even though there is a growing knowledge of the efficacy of different antidepressants and their range of utility, it is still not possible to predict with accuracy response to antidepressants in mood and anxiety disorders, or to find meaningful differences between antidepressants. Apart from evidence that tricyclic antidepressants (TCA) are probably more effective for the treatment of severely depressed patients, no differences in the efficacy of TCAs versus SSRIs (selective serotonin reuptake inhibitors) have been found for the treatment of mood and anxiety disorders. The present research is therefore an attempt to detect any differences in the efficacy of different antidepressants. Therefore, response to treatment with TCAs versus SSRIs has been examined within a broad range of patients suffering from either a mood disorder, an anxiety disorder, or both. In doing this, the selection bias associated with the use of single diagnostic categories is presumably reduced. Alternative models for the identification of subgroups of patients responding differentially to antidepressant treatment were explored. Of particular interest were the role of primary diagnosis and the role of temperament to detect response differences. The major finding was that primary diagnosis (i.e., diagnosis at first episode in a patient's lifetime) appears to be a more valuable concept for differentiation of antidepressant treatment response than current DSM categorisation as a mood and/or anxiety disorder
