Objective: Comorbid anxiety disorders may result in worse depression treatment outcomes. The authors evaluated the effect of comorbid panic disorder and posttraumatic stress disorder (PTSD) on response to a collaborative-care intervention for late-life depression in primary care.

Methods: A total of 1,801 older adults with depression were randomized to a collaborative-care depression treatment model versus usual care and assessed at baseline, 3, 6, and 12 months, comparing differences among participants with comorbid panic disorder (N=262) and PTSD (N=191) and those without such comorbid anxiety disorders.

Results: At baseline, patients with comorbid anxiety reported higher levels of psychiatric and medical illness, greater functional impairment, and lower quality of life. Participants without comorbid anxiety who received collaborative care had early and lasting improvements in depression compared with those in usual care. Participants with comorbid panic disorder showed similar outcomes, whereas those with comorbid PTSD showed a more delayed response, requiring 12 months of intervention to show a significant effect. At 12 months, however, outcomes were comparable. Interactions of intervention status by comorbid PTSD or panic disorder were not statistically significant, suggesting that the collaborative-care model performed significantly better than usual care in depressed older adults both with and without comorbid anxiety.

Conclusions: Collaborative care is more effective than usual care for depressed older adults with and without comorbid panic disorder and PTSD, although a sustained treatment response was slower to emerge for participants with PTSD. Intensive and prolonged follow-up may be needed for depressed older adults with comorbid PTSD.