Patients with medically unexplained symptoms and their significant others: illness attributions and behaviors as predictors of patient functioning over time.

Objective: Previous research suggests that medically unexplained symptoms (MUS) are maintained in an interpersonal context. The current study examined MUS concurrently and prospectively by measuring specific interpersonal predictors of symptom severity and health care use.

Methods: A total of 127 patients with MUS and their significant others were recruited through primary care offices and assessed with self-report questionnaires and structured interviews about illness attributions, illness behavior and responses, relationship quality, symptom severity, and health care use at baseline and 6-month follow-up.

Results: Illness attributions and interpersonal illness behaviors of patients with MUS were cross-sectionally associated with illness attributions and responses of the patients' significant others. Relationship quality was related to specific illness behaviors and responses. Symptom severity at baseline was predicted by patients' somatic illness attributions. Symptom severity at 6-month follow-up was predicted by somatic illness attributions of patients and withdrawal of patients' significant others at baseline, but these predictors became insignificant when correcting for baseline symptomatology. Health care use at baseline was predicted by a greater amount of coping behavior and higher anxiety scores of patients, and health care use at 6-month follow-up was predicted by more attention-seeking behaviors and health care use of patients at baseline.

Conclusion: The results document the interpersonal influences on the maintenance of MUS. The perspective of significant others should be considered for enhancement of psychological approaches to the treatment of patients with MUS.