[Criteria for somatization studied in an outpatient clinic for general internal medicine]

To compare the evolution of bodily symptoms and the frequency of medical consultation using three different operational definitions of 'somatization'.

Descriptive follow-up study.

General Internal Medicine Outpatient Clinic of Leiden University Hospital, the Netherlands.

Information about physical and psychic symptoms and about the somatic-medical diagnosis was collected in a group of 158 newly referred patients. The concept of 'somatization' was operationalized in three ways: a) seeking medical consultation for somatically unexplained symptoms; b) seeking medical consultation for somatically unexplained symptoms combined with an anxiety disorder or a depressive disorder according to the 'present state examination'; c) seeking medical consultation for somatically unexplained symptoms combined with a somatization disorder or hypochondria according to the Diagnostic and statistical manual of mental disorders (DSM) III R criteria. After a follow-up period of 1.2 years, information was collected from the entire study group about the evolution of the physical symptoms and the frequency of medical consultation.

Patients with somatically unexplained symptoms combined with a somatization disorder or hypochondria were characterized in the follow-up by numerous physical symptoms and a high frequency of medical consultation. Compared with the other patients with unexplained symptoms, they visited the general practitioner during the follow-up period 2.5 times as often, saw specialists twice as often and were admitted to a 'somatic' hospital, 6 times as often.

Using criteria of low restrictiveness for somatization, a large group of patients were identified with a relatively normal (average) illness behaviour. Using more restrictive criteria led to identification of a smaller group with more extreme illness behaviour.