Comorbidity and the treatment of principal anxiety disorders in a naturalistic sample.

This study examined the impact of comorbidity on treatment outcome and the effects of cognitive behavioral therapy (CBT) for anxiety and depressive disorders on comorbid disorders in a naturalistic sample of 150 patients presenting to an anxiety disorders clinic. The following results were observed across principal (i.e., most severe) diagnoses. Patients with comorbid anxiety and depressive disorders presented for treatment with higher severity of their principal disorder than patients without comorbidity. However, the presence of comorbidity did not predict dropout or poor treatment response, and patients demonstrated significant improvement in their principal disorders regardless of comorbidity. The frequency of clinically severe and subclinical (i.e., not severe enough to meet diagnostic criteria) comorbid conditions decreased significantly over the course of treatment. The implication of these findings for the classification and treatment of emotional disorders is discussed.