Objective: The narrow ICD-10 and DSM-IV definition of hypochondriasis makes it rarely used yet does not prevent extensive diagnosis overlap. This study identified a distinct hypochondriasis symptom cluster and defined diagnostic criteria.
Method: Consecutive patients (N=1,785) consulting primary care physicians for new illness were screened for somatization, anxiety, depression, and alcohol abuse. A stratified subgroup of 701 patients were interviewed with the Schedules for Clinical Assessment in Neuropsychiatry and questions addressing common hypochondriasis symptoms. Symptom patterns were analyzed by latent class analysis.
Results: Patients fell into three classes based on six symptoms: preoccupation with the idea of harboring an illness or with bodily function, rumination about illness, suggestibility, unrealistic fear of infection, fascination with medical information, and fear of prescribed medication. All symptoms, particularly rumination, were frequent in one of the classes. Classification allowed definition of new diagnostic criteria for hypochondriasis and division of the cases into "mild" and "severe." The weighted prevalence of severe cases was 9.5% versus 5.8% for DSM-IV hypochondriasis. Compared with DSM-IV hypochondriasis, this approach produced less overlap with other somatoform disorders, similar overlap with nonsomatoform psychiatric disorders, and similar assessments by primary care physicians. Severe cases of the new hypochondriasis lasted 2 or more years in 54.3% of the subjects and 1 month or less in 27.2%.
Conclusions: These results suggest that rumination about illness plus at least one of five other symptoms form a distinct diagnostic entity performing better than the current DSM-IV hypochondriasis diagnosis. However, these criteria are preliminary, awaiting cross-validation in other subject groups.