What’s Next for Somatic Symptom Disorder?

DSM-5 made major changes by introducing the diagnosis of somatic symptom disorder. Our commentary describes the contours of this new diagnosis and provides an overview of the rationale for the changes. We also make some cautious predictions of how the field will develop in the next 10 years in order to base clinical practice on a sound scientific footing.

Somatic symptom disorder represents a consolidation of several disorders (primarily somatization disorder, undifferentiated somatoform disorder, and hypochondriasis) that were noteworthy for their high degree of overlap. The criteria for somatization disorder were difficult to use and so restrictive that the diagnosis was rarely made (1). In DSM-III, the diagnosis required 14 symptoms in women and 12 in men from a list of 37. In DSM-IV, diagnosis required four pain symptoms, two gastrointestinal symptoms, one sexual symptom, and one neurological symptom.

In contrast, the criteria for undifferentiated somatoform disorder created far too low a diagnostic threshold. Clinicians seldom used these diagnostic labels, and psychiatric epidemiology rarely included their assessment. However, the major limitation of the DSM-III and DSM-IV somatoform diagnoses was the overemphasis on medically unexplained symptoms as their hallmark (2). The reliability of diagnosing medically unexplained symptoms is poor, and the emphasis on these symptoms promotes mind-body dualism (3). In fact, psychiatric and general medical disorders commonly co-occur. “Somatizing” frequently occurs in patients with diagnosed medical disorders, amplifying “explained” symptoms.

The diagnosis of somatic symptom disorder is established when three criteria are met: distressing and impairing somatic symptoms are present; the symptoms are persistent (i.e., >6 months); and the symptoms are associated with abnormal and excessive thoughts, feelings, and behaviors, typically manifested by disproportionate catastrophizing, high levels of anxiety, and illness behavior. For example, following an uncomplicated myocardial infarction, a man is advised to resume normal activities, but he worries constantly about a recurrence and experiences dizziness, dyspnea, and palpitations unrelated to exertion, he restricts his activities, and he checks his pulse hourly. Note that the diagnosis of somatic symptom disorder in this case is based on criteria that are present rather than lack of explanation of symptoms; furthermore, these criteria focus on territory familiar to psychiatrists and psychologists—thoughts, feelings, and behaviors. The removal of the emphasis on medically unexplained symptoms allows a focus on patient suffering without questioning its legitimacy or “reality.” Furthermore, finding somatic symptoms of unclear etiology is not sufficient to make this diagnosis. In the absence of abnormal thoughts, feelings, and behaviors, patients with irritable bowel syndrome, chronic fatigue, or fibromyalgia would not qualify for a diagnosis of somatic symptom disorder.