Anxiety in primary care: a frontier for mental health services research.

The article by Stein and colleagues1 in this problem highlights a crucial problem in I medical care, namely, the need for additional attention to the identification and treatment of anxiety disorders. As the authors point out, services research addressing the impact of mental health symptoms or disorders in medical settings has focused largely on the impact and treatment of depression.2'3 However, data from Stein et al and other mental health services research groups strongly suggest that anxiety disorders pose a frequently unrecognized and undertreated public health problem, with prevalence rates and impact often equivalent to or greater than depression. A recent report by Kunik et al,4 for example, found higher prevalence of anxiety disorders than depression in a sample of patients with chronic obstructive pulmonary disease. A number of studies also have demonstrated independent and/or additive effects of anxiety, relative to depression, related to patient disability status,5'6 coronary heart disease risk factors,7 and mortality.8 Although the overlap and distinctiveness of anxiety and depression have received significant attention in traditional psychologic and psychiatric literatures,9 mental health services research has only recently begun to investigate the differential roles of anxiety and depression as they affect health status and medical care. As Stein et al suggest, a number of studies are beginning to test the value of empirically based, collaborative care models of treatment for anxiety in primary care settings,1? -1 but of critical importance at this juncture is the need to evaluate what kinds of studies are still needed, what methodological features are most critical for this work, and how best to translate empirical findings into the public sector. The Collaborative Care for Anxiety and Panic (CAPP) Study is one of the most comprehensive ongoing programmatic efforts to investigate the impact and treatment of anxiety (in particular, panic disorder) in primary care, serving as an excellent model of anxiety-focused mental health services research. This relatively new field is a frontier for additional work, and the Stein et al report from the CAPP study highlights central issues for future research and key methodological features to consider. First, continued attention needs to be given to the differential diagnosis and relative impact of anxiety disorders and depression. Part of this issue involves the need for accurate differentiation of anxiety and depression, a consistently complicated task that is made even more challenging by the complex clinical picture of patients with coexistent medical illness.13 Of equal importance, however, is the need to focus carefully on distinguishing separate anxiety disorders. The anxiety disorders are a diverse set of clinical syndromes characterized by quite different clinical features14 that do not always affect functional status, quality of care, cost, or treatment outcome in uniform ways. Marciniak et al,15 for example, demonstrated that medical costs associated with post-traumatic stress disorder were elevated relative to other anxiety disorders. Rollman et al10 reported reductions in severity of anxiety after a collaborative care intervention for patients with panic disorder alone and panic disorder with generalized anxiety disorder (GAD), but not for patients with GAD alone. Although