Numerous studies of primary care populations have found that many somatizing patients have diagnosable anxiety or depressive disorders that are commonly undetected by general practitioners. In a study of two family medicine clinics in Canada, for example, Kirmayer and Robbins (1991a) found that 11% of patients met DSM-III criteria for major depression and/or anxiety disorder, and almost three–quarters of these patients had presented with exclusively somatic symptoms. Similarly, in a survey of 15 primary care practices in the Greater Manchester area of England, Bridges and Goldberg (1985) found anxiety and depressive disorders that were unrelated to physical disease in almost 25% of patients, with more than three–quarters of the patients seeking medical help for somatic symptoms; although general practitioners detected the majority of psychiatric disorders in patients who sought help for psychological symptoms, only half of the psychiatric disorders were detected when somatization was present. An American study found clinical depression in 12% of ambulatory medical patients in a prepaid health program, and demonstrated a failure of primary care physicians to diagnose the depression in 50% of cases (Nielson & Williams, 1980). Studies of patients with somatization disorders referred to psychiatrists by primary care physicians have also demonstrated high rates of comorbidity with other psychiatric disorders, especially major depression, panic disorder, and generalized anxiety disorder (Brown, Golding & Smith, 1990; Liskow et al., 1986).