The distinction between "medically unexplained" and "medically explained" in the context of somatoform disorders

Medically unexplained symptoms (MUS) currently constitute the main diagnostic criterion of somatoform disorders. It has been proposed that the required dichotomization of somatic complaints into MUS and medically explained symptoms (MES) should be abandoned in DSM-V. The present study investigated complaints in the general population in order to evaluate the relevance of a distinction between MUS and MES.

Three hundred twenty-one participants from a population-based sample were interviewed by telephone to assess symptoms present during the previous 12 months. Complaints were examined in terms of health care use, diagnoses made by the physician and degree of impairment. At the 1-year follow-up, 244 subjects were re-interviewed in order to explore the stability of symptoms.

The complaints frequently prompted participants to seek medical health care (several pain and pseudoneurological symptoms led to a doctors' visit in >80 % of cases), although etiological findings rarely suggested a medical pathology (occasionally <30 %). MUS and MES proved, to an equal degree, to impair individuals and prompt a change in lifestyle. Pain caused the worst impairment compared with other symptoms. The most prevalent MUS and MES were characterized by a transient course (approximately 60 % remitted, 55 % newly emerged to follow-up), although various unexplained pain complaints tended to be persistent (e.g., back pain 67 %). Remarkably, the appraised etiology as explained or unexplained changed from baseline to follow-up in many persisting symptoms (20 % MUS → MES, 50 % MES → MUS).

In principal, MUS and MES resulted in comparable impairment and stability. Due to conceptual and methodological difficulties, classification criteria for somatoform disorders should not be restricted to somatic aspects of the symptomatology.