Mental health articles

Undifferentiated somatoform disorder was apparently created to capture a sizable proportion of patients with multiple, chronic, physical symptomatology similar to somatization disorder, but do not meet the eight physical-symptom requirement. This diagnosis is given to persons with one or several medically unsupported physical complaints that are of at least 6-months duration and are not due to the effects of a substance. The symptom or symptoms have to cause clinically significant distress in a number of functional domains. The diagnosis of undifferentiated somatoform disorder is precluded if physical symptoms occur in the course of another mental disorder and if the symptom are intentionally produced or feigned.

Undifferentiated somatoform disorder, when compared to somatization disorder, is apparently less disabling and has a more variable course. Nonetheless, it is likely that undifferentiated somatoform disorder has a putative etiology similar to that of somatization disorder. However, the utility of undifferentiated somatoform disorder as a diagnostic category is questionable. It is a relatively recent addition to the DSM, difficult to use in a clinical setting, possibly overly inclusive (one unexplained symptom is enough for a diagnosis), and lacks validity data. A number of investigators attempted a more systematic approach to somatic presentations that do not meet a formal diagnosis of somatization disorder. In two earlier studies, Escobar and his colleagues demonstrated the utility of the Somatic Symptom Index  as an abridged version of the somatization construct. The SSI consisted of four symptoms for men and six for women. Most recently, Escobar, Waitzkin, Silver, Gara, and Holman examined abridged somatization in primary care. Using the Composite International Diagnostic Interview (CIDI), 1456 patients were recruited from a universityaffiliated outpatient clinic. The CIDI probed for symptoms of somatization, hypochondriasis, generalized anxiety, panic, agoraphobia, simple phobia, dysthymia, and major depression. The sample included four ethnic groups: U.S.-born nonLatinos (whites), U.S. born Latinos, Mexican immigrants, and Central American immigrants. The investigators found that one-fifth of the total sample met a diagnosis of abridged somatization and that somatizers had higher levels of psychiatric comorbidity and functional disability than nonsomatizers. In addition, the authors found evidence for a new series of abridged somatization subtypes based upon the number of organ body systems involved (‘‘simple’’ versus ‘‘polymorphous’’), the type of body system involved (sevenorgan system cluster, two distinct three-symptom clusters, and three single-organ system subtypesgenitourinary, cardiorespiratory, and headache), and discrete (one-third of the sample with abridged somatization did not meet criteria for any other psychiatric disorder) versus comorbid (two-thirds of the sample with abridged somatization met criteria for other lifetime psychiatric disorders).

Preliminary data on 108 psychiatric inpatients demonstrated that three unexplained symptoms for men and five for women out of thirty-three DSM-IV somatization symptoms were equivalent to Escobar SSI 4,6. Other ways of conceptualizing subthreshold somatization disorder have been put forward by other researchers. Robbins, Kirmayer, and Hemami used latent variable models to test ‘‘functional syndromes’’ in 686 primary care patients. Symptom items were derived from the National Institute of Mental Health Diagnostic Interview Schedule and were made to approximate diagnoses of fibromyalgia syndrome, chronic fatigue syndrome, and irritable bowel syndrome. Three models were tested for goodness of fit: the f irst model assumes that all forms of functional symptoms may be traced to a single underlying construct of somatic distress; the second model tests whether functional symptoms common to f ibromyalgia, chronic fatigue, and irritable bowel can be subsumed under the physical symptoms for depression and anxiety; and the third model tests the convergent validity of these syndromes as discrete from one another and from depression and anxiety. The data indicated that patients with functional symptoms (multiple medically unexplained somatic symptoms) should be categorized in two groups: one group with distress across multipleorgan systems often associated with another psychiatric disorder; the second group with concerns limited to a single-organ system.

Finally, Kroenke and his colleagues  proposed multisomatoform disorder as an alternative to undifferentiated somatoform disorder. The authors defined multisomatoform disorder as three or more currently bothersome unexplained physical symptoms (from a fifteenitem symptom checklist) that are present more often than not for at least 2 years. Kroenke et al. then used data from the Primary Care Evaluation of Mental Disorders  and Somatization in Primary Care Studies (N = 258) to determine the optimal threshold of a fifteen-item checklist and to determine the concordance between multisomatoform disorder and somatization disorder. The optimal threshold for pursuing a diagnosis of multisomatoform disorder was seven or greater. The majority of multisomatoform disorder patients met a diagnosis of either full somatization disorder or abridged somatization disorder.

The authors also found that multisomatoform disorder was intermediate between abridged and full somatization disorder in functional impairment, psychiatric comorbidity, family dysfunction, and health care utilization and charges. The other advantage of the multisomatoform disorder diagnosis is that it takes less time to administer than Escobar’s SSI 4,6 and Rief’s SSI 3,5. In sum, undifferentiated somatoform disorder is likely to continue being problematic in its application, but the number of persons subsumed under such a label necessitates continued efforts toward improving its diagnostic usefulness. Other subthreshold versions of somatization disorder have been developed, and their utility is more promising. Among them, multisomatoform disorder is most promising; this diagnostic category affords greater specificity in defining physical symptom requirements.

Tags: Criteria, disorder, somatoform, symptoms, undifferentiated somatoform disorder