The relationship between anxiety and depression: a clinical comparison of generalized anxiety disorder, dysthymic disorder, panic disorder, and major depressive disorder.

This study examined the relationship between the chronic disorders, generalized anxiety disorder (GAD) and dysthymic disorder (DD), and the more acute disorders, panic disorder (PD) and major depressive disorder (MDD) in 110 psychiatric outpatients with diagnoses of either PD, MDD, GAD, or DD. Pure, mixed, and early-/late-onset forms of the chronic disorders were compared with each other and then with PD and MDD on clinical measures and psychiatric history. Minimal differences were found between pure GAD and mixed GAD or between pure DD and mixed DD. The chronic disorders, DD and GAD, had distinct clinical symptom profiles when compared with each other and appeared more closely related to their parent disorders than to each other. However, despite these similarities, there were significant differences between DD and MDD in contrast to the minimal differences between GAD and PD, providing less support for GAD as a valid diagnostic category separate from PD. Comparisons of early-/late-onset DD and GAD showed more severe symptoms in late-onset DD, in contrast to more severe symptoms in early-onset GAD. These varying patterns of symptom severity may warrant study for further syndromal delineation.