The influence of comorbid anxiety disorders on outcome in major depressive disorder

Coexisting anxiety symptoms and comorbid anxiety disorders are common in patients with major depressive disorder. This review examines three aspects of the relationship between major depressive disorder and comorbid anxiety disorders: whether the comorbid condition is more severe than “pure” major depression; whether the comorbid condition is associated with worse clinical outcomes than are seen in major depressive disorder alone; and whether the response to antidepressant treatment differs between depressed patients with or without comorbid anxiety disorders. Although not all evidence is consistent, in general terms, the presence of comorbid anxiety disorders in patients with major depressive disorder is associated with greater severity of symptoms and more pronounced impairment. The course of illness is less favorable in patients with the comorbid condition, and relatively fewer depressed patients respond to antidepressant treatment and achieve remission of symptoms if affected by comorbid anxiety disorders. There is a need for randomized placebo-controlled studies specifically in patients with comorbid major depressive disorder and anxiety disorders, in order to determine whether this patient group differs from those with “pure” major depression in its responsiveness to pharmacological or psychological interventions. <br/