Causal illness attributions in somatoform disorders: associations with comorbidity and illness behavior.

Objective: To compare causal illness beliefs between patients with unexplained physical symptoms and different comorbid disorders and to assess the association of causal illness beliefs with illness behavior.

Methods: We examined a sample of 233 patients attending treatment in primary care. Inclusion criteria were "unexplained physical symptoms." All patients were investigated using structured interviews and self-rating scales [Screening for Somatoform Symptoms (SOMS), Beck Depression Inventory (BDI), Beck Anxiety Inventory, and a 12-item instrument to assess causal attributions]. By means of factor analysis, the following illness attributions were considered: vulnerability to infection and environmental factors, psychological factors, organic causes including genetic and aging factors, and distress (including exhaustion and time pressure).

Results: Most patients reported multiple illness attributions. The more somatoform symptoms patients had, the more explanations in general they considered. Especially for vulnerability and organic illness beliefs, patients with somatoform symptoms had increased scores. Comorbidity with depression and with anxiety disorders was associated with more psychological attributions. Even when the influence of somatization, depression, and anxiety is controlled for, illness beliefs still showed associations with illness behavior. Organic causal beliefs and vulnerability attributions were associated with a need for medical diagnostic examinations, increased expression of symptoms, increased illness consequences, and bodily scanning.

Conclusions: Multiple causal attributions can coexist demonstrating different associations with comorbid depression and illness behavior.