Once the clinician recognizes that either somatization disorder or undifferentiated somatoform disorder is a diagnostic possibility in a given patient, he or she must then actually diagnose the disorder. The diagnostic criteria for these disorders have gone through many iterations, including the most recent ones for DSM-IV.

Diagnostic Criteria
Somatization disorder A brief history of the evolution of the diagnostic criteria for somatization disorder may be helpful. A series of papers published between 1951 and 1953 presented the first contemporary conceptualization of what is now called somatization disorder. From these studies, the authors concluded that the disorder was a definable clinical syndrome with a characteristic clinical picture. A decade later, further work showed diagnostic consistency of this disorder over time, reconfirmed the work indicating a definable clinical syndrome, and noted a uniform clinical course.

Beginning in 1970 and continuing until the publication of DSM-III (American Psychiatric Association 1980), the eponym Briquet’s syndrome was used for somatization disorder. Although it was decided that Briquet’s syndrome would be incorporated into DSM-III as part of the new diagnostic nomenclature, a separate decision was made to drop all eponyms from DSM-III; hence, Briquet’s syndrome became somatization disorder. The diagnostic criteria for the disorder were simplified somewhat for DSM-III but remained cumbersome. In DSM-III-R, the criteria were only minimally modified.

The diagnostic criteria for somatization disorder in DSM-IV (

Table 58-1) were extensively revised in an attempt to make them easier to use and more helpful to the clinician. Briefly, a history of many physical complaints beginning before age 30 years and occurring over a period of several years for which treatment has been sought or which has produced significant impairment in social or occupational functioning is now required. This symptom must not be fully explained by a known general medical condition or the direct effects of a substance, or if related to a general medical condition, the resulting complaints or impairment should be in excess of what is expected from the history, physical examination, and laboratory findings. Instead of requiring a certain number of positive symptoms from the list of 37 symptoms, the new diagnostic criteria require 4 pain symptoms from different sites, 2 gastrointestinal symptoms, 1 sexual symptom, and 1 pseudoneurological symptom. The DSM-IV field trials found these criteria to have a high concordance with DSM-III-R criteria and other previous diagnostic criteria.

Undifferentiated somatoform disorder DSM-III did not contain a diagnostic entity entitled undifferentiated somatoform disorder. This separate diagnostic category was created for DSM-III-R, based on the recognition that many patients do not meet the full diagnostic criteria for somatization disorder. The category has been retained in DSM-IV. The criteria for undifferentiated somatoform disorder are listed in

Table 58-2. They require one or more physical complaints that cannot be explained by a known general medical condition or pathophysiological mechanism, or when they are related to a general medical condition, the resulting complaints or impairment in social, occupational, or other important areas is grossly in excess of expectations. The symptom must cause clinically significant distress or social impairment. The duration of the disturbance must be at least 6 months. Recently, a new diagnostic formulation called multisomatoform disorder has been proposed, which is simpler to use and may describe a similar group of patients.

Gender
Although the original reports of somatization disorder and its predecessors noted the occurrence of this disorder in women, somatization disorder and undifferentiated somatoform disorder have been reported in men as well. The ECA data indicated that the female-to-male ratio is 10:1, whereas primary care data indicate that the ratio may be as low as 5:1. Undifferentiated somatoform disorder is more prevalent in females; however, the female-to-male ratio for this disorder according to ECA data is only 4:3.

Screening Instruments for Somatization Disorder
One approach clinicians can take to ensure that they correctly diagnose and, hence, correctly treat somatization disorder is to use screening instruments. Three published screening instruments, two developed by Othmer and DeSouza and one developed by Swartz et al., are currently in clinical use. Study results indicate that these screening instruments perform similarly, that they can obviously be applied over a briefer period than the full diagnostic criteria for the disorder, and that they have high positive predictive values in general medical and consultation settings.