An international study of the relation between somatic symptoms and depression

Patients with depression, particularly those seen by primary care physicians, may report somatic symptoms, such as headache, constipation, weakness, or back pain. Some previous studies have suggested that patients in non-Western countries are more likely to report somatic symptoms than are patients in Western countries. We used data from the World Health Organization's study of psychological problems in general health care to examine the relation between somatic symptoms and depression. The study, conducted in 1991 and 1992, screened 25,916 patients at 15 primary care centers in 14 countries on 5 continents. Of the patients in the original sample, 5447 underwent a structured assessment of depressive and somatoform disorders.

A total of 1146 patients (weighted prevalence, 10.1 percent) met the criteria for major depression. The range of patients with depression who reported only somatic symptoms was 45 to 95 percent (overall prevalence, 69 percent; P=0.002 for the comparison among centers). A somatic presentation was more common at centers where patients lacked an ongoing relationship with a primary care physician than at centers where most patients had a personal physician (odds ratio, 1.8; 95 percent confidence interval, 1.2 to 2.7). Half the depressed patients reported multiple unexplained somatic symptoms, and 11 percent denied psychological symptoms of depression on direct questioning. Neither of these proportions varied significantly among the centers. Although the overall prevalence of depressive symptoms varied markedly among the centers, the frequencies of psychological and physical symptoms were similar.

Somatic symptoms of depression are common in many countries, but their frequency varies depending on how somatization is defined. There is substantial variation in how frequently patients with depression present with strictly somatic symptoms. In part, this variation may reflect characteristics of physicians and health care systems, as well as cultural differences among patients.