Anxiety disorders are the most prevalent psychiatric disorders in the United States (Table 91–2), with simple phobias being the most common (9 percent) and social phobia (8 percent) being the most often observed (Tables 91–3 and 91–4). A survey of adult primary care patients (n= 637) enrolled in a health maintenance organization revealed that 10 percent had untreated anxiety disorders.

Unfortunately, anxiety disorders, though common, remain largely undiagnosed and undertreated. Stereotyped as the “worried well,” patients with anxiety disorders such as phobias, panic disorder, and generalized anxiety disorder have substantially higher rates of health service utilization, increased social and role disability, diminished quality of life, and poor health outcomes. Moreover, the comorbidity of anxiety and affective disorders is substantial. Nearly 60 percent of patients with major depression in the National Comorbidity Survey suffered from a comorbid anxiety disorder. Indeed, patients with mixed anxiety and depressive symptoms (or comorbid anxiety and depressive syndromes) suffer increased emotional disability as well as poorer social and role function in comparison to patients with either condition alone. After elective catheterization, the physical disability of patients with CAD at 1 year of follow-up was associated with the severity of these patients’ anxiety and depressive symptoms at catheterization, not with the number of main coronary vessels stenosed.

The prevalence of anxiety disorders in patients with CVD has been largely understudied, with most studies focusing on patients with mitral valve prolapse or individuals referred for evaluation of chest pain. Substantial numbers of patients each year who undergo coronary angiography because of symptoms of chest pain (yet have normal coronary arteries) are thought to have anxiety disorders such as panic disorder. Subsequently categorized as having “atypical chest pain,” these patients may suffer chest pain in response to anxiety and/or hyperventilation.

However, a large, multicity survey of 875 primary care outpatients revealed that patients with CHF or MI exhibited a point prevalence rate of at least one anxiety disorder (panic disorder, phobia, or generalized anxiety disorder) of 18 percent (Table 91–5). Whether the prevalence of anxiety disorders is elevated in patients who are hospitalized for CAD (e.g., elective coronary catheterization, post MI, or unstable angina) remains to be determined.

A small number of prospective epidemiologic studies (which control for many of the commonly accepted risk factors for IHD) indicate an increased relative risk of nonfatal and fatal CVD events in patients with anxiety symptoms, even among individuals who have “simple” phobias (e.g., claustrophobia and fear of illness, heights, crowds, or going out alone). A dose-response relationship has been demonstrated in these studies, with minimal symptoms of anxiety sufficient to elevate risk, suggesting that nonclinical, or “normal” levels of anxiety may play some role in the development of IHD. Moreover, an ancillary study of 348 CAST and CAST II participants who had asymptomatic ventricular arrhythmias after MI and were treated with placebo revealed that stressful life events during the initial 4 months of participation in CAST trial and higher anxiety were predictive of mortality independently of the effects of physiologic variables such as diabetes and ejection fraction.