Comorbidity of anxiety and depressive disorders: issues in conceptualization, assessment, and treatment.

The purpose of this review is to provide a clinically relevant analysis of issues concerning comorbidity among anxiety and depressive disorders. The co-occurrence of social anxiety disorder (SAD) and generalized anxiety disorder (GAD) with depressive disorders is highlighted as an illustration. Data on prevalence, rates of comorbidity, order of onset, course, and functional impairment associated with these disorders, in both the general population and clinical samples, are examined. The second half of the review focuses on discussion of practical issues concerning assessment and treatment of comorbid anxiety and depressive syndromes.Available evidence suggests that comorbidity among SAD, GAD, and the depressive disorders is substantial and pervasive. Co-occurrence of these syndromes is typically characterized by a chronic course with clinically significant impairment in social and occupational functioning. SAD and GAD precede the onset of major depression in a majority of cases and appear to be risk factors for developing major depression. Clinicians encountering patients with primary complaints of anxiety or depression should carefully assess for the presence of comorbid symptoms and syndromes. Treatment outcome research suggests that pharmacotherapy and psychosocial therapy (cognitive-behavior therapy in particular) both represent viable first-line treatment alternatives. However, with increasing severity of depression, pharmacotherapy is indicated as a primary intervention. The authors recommend increased efforts in screening and detection, more clinical trials that include patients with comorbid syndromes and symptoms, and continued research on the integration of pharmacological and psychotherapeutic treatments.