Effects of co-occurring depression on treatment for anxiety disorders: analysis of outcomes from a large primary care effectiveness trial.

OBJECTIVE

Co-occurring depression is common in patients seeking treatment for anxiety; however, the literature on the effects of depression on anxiety treatment outcomes is inconclusive. The current study evaluated prescriptive and prognostic effects of depression on anxiety treatment outcomes in a large primary care sample.

METHOD: Data were analyzed from a randomized controlled effectiveness trial that compared coordinated anxiety learning and management (CALM) to usual care. The study enrolled 1,004 patients between June 2006 and April 2008. Patients were referred by their primary care provider and met DSM-IV criteria for generalized anxiety disorder, panic disorder, posttraumatic stress disorder, and/or social anxiety disorder. They were treated for approximately 3 to 12 months with CALM (computer-assisted cognitive-behavioral therapy, medication management, or their combination) or usual care. Outcomes were evaluated by blinded assessment at 6, 12, and 18 months. Effects of baseline major depressive disorder (MDD) on anxiety symptoms, anxiety-related disability, and response/remission rates were evaluated using statistical models accounting for baseline anxiety and patient demographics.

RESULTS

MDD did not moderate the effects of CALM (relative to usual care) on anxiety symptoms, anxiety-related disability, or response/remission rates. Greater improvements in anxiety symptoms and anxiety-related disability were observed in depressed patients, regardless of treatment assignment (P values < .005). However, cross-sectionally depressed patients displayed higher anxiety symptom and anxiety-related disability scores at baseline and all subsequent assessments (P values < .001). Depressed patients also displayed lower remission rates at each follow-up (P values < .001).

CONCLUSIONS

CALM had comparable advantages over usual care for patients with and without MDD. Depressed patients displayed more severe anxiety symptoms and anxiety-related disability at baseline, but their clinical improvement was substantial and larger in magnitude than that observed in the nondepressed patients. Results support the use of empirically supported interventions for anxiety disorders in patients with co-occurring depression.

TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT00347269.