Somatization in Family Practice: Comparing 5 Methods of Classification

Background: It has been suggested that patients with somatoform disorders are high utilizers of medical care, yet interpretation of studies has been difficult because of variant methods of diagnosis. The goal of this study was to compare 5 different methods of classification on the same group of subjects and to examine prevalence rates of somatoform disorders and medical utilization.

Method: Subjects completed a demographic questionnaire in the physician’s office and the somatization section of the Diagnostic Interview Schedule (DIS) by telephone. Subsequently, their medical charts were examined. Using the 5 methods of diagnosis, somatizers were compared with nonsomatizers for level of utilization of medical services. The setting was a medical school-based family practice residency training center. Participants were 119 patients waiting to see their family doctors. The main outcome measures were prevalence of somatization symptoms and chart information (utilization, number of health problems).

Results: One subject met the Diagnostic and Statistical Manual (DSM-IV)-based DIS criteria for somatization disorder. With the Bucholz modification for scoring the DIS, 10 subjects were diagnosed with somatization disorder. With the abridged Escobar criteria of 6 symptoms, 7 subjects met diagnostic criteria, while 28 met the criteria for multisomatoform disorder of 3 symptoms, as suggested by Kroenke. The diagnosis of undifferentiated somatoform disorder, requiring only 1 unexplained symptom, was obtained by 94 of the subjects.

Conclusion: Findings from this study revealed widely divergent prevalence rates of somatoform disorders, depending on methods of diagnosis used. Correlation with rates of medical utilization is suggested as an external criterion for validating diagnostic methods.