An adoption study of somatoform disorders. II. Identification of two discrete somatoform disorders.

linical heterogeneity among women with prominent somatization was studied in a population of 859 adopted women in Sweden. We distinguished two groups of "somatizers" who differ in both the diversity of their somatic complaints and the frequency of their periods of disability. Type 1 or high-frequency somatizers have a high frequency of psychiatric, abdominal, and back complaints. Type 2 or diversiform somatizers have less frequent disability, but a greater diversity of complaints per occasion than do other somatizers. Diversiform somatizers have psychiatric chief complaints or backache in a lower proportion of their sick periods than either high-frequency somatizers or nonsomatizers. Quantitative measures of frequency and diversity were derived in a series of discriminant analyses. The distribution of scores on these measures indicated that high-frequency somatization and diversiform somatization were discrete disorders with little clinical overlap and rare intermediate cases. This demonstration of two discrete types of somatizers was confirmed in a replication sample.