Krankheitsverhalten von Patienten mit somatoformen Störungen : Beschreibung, Erfassung und assoziierte Faktoren

Illness behavior can be considered as both a consequence and as part of an amplification process maintaining somatoform disorders (Kirmayer & Taillefer, 1997). Besides, it results in a highly economic relevance for health care systems (Hiller et al., 2003). In this thesis different aspects of illness behavior in patients with somatoform disorders were studied, focusing especially on health care utilization. The first study’s aim was to investigate the pattern and the heterogeneity of illness behaviors in patients with medically unexplained physical symptoms. We aimed at empirically identifying subgroups with different degrees of illness behaviors and at detecting factors that may be indicators of illness behaviors within these groups. We found two distinct clusters: a low and a high illness behavior cluster. Increased health anxiety was associated with illness behavior in both clusters. The results of our study strongly suggest that not all patients develop the tendency to exhibit a very high rate of illness behaviors. The systematic assessment of health care use is essential for the health economic evaluation of psychotherapy as well as to ensure comparability across studies. In the second study we developed and evaluated a self-report instrument for assessing health care utilization. High agreement between questionnaire and interview and a good differentiation between groups of somatizing patients with different somatization scores are indicators of the practicability of the HCU-Q. The aim of the third study of this thesis was to describe the health care use of patients with somatoform disorders across the entire somatoform diagnostic spectrum and to differentiate between patients with and without comorbid mental disorders. In addition, we examined potential mediating factors which exert influences on the link between somatization and health care use. We found that patients fulfilling criteria of DSM-IV somatization disorder had a significantly higher number of doctor visits than patients with undifferentiated somatoform, and somatoform pain disorder. In most health care use variables, patients with comorbid mental disorders did not differ from patients without comorbidities. Potential mediator effects were found for health anxiety and disability, but not for depression and anxiety. The results enable us to better understand which factors could drive somatizing patients to use health care services extensively. The studies conducted within this thesis underline the importance of illness behaviors and result in a better understanding of these behaviors in patients with somatoform disorders. The results indicate that not all patients engage in very high levels of illness behaviors and that different needs are associated with patients’ drive to consult their doctor. These aspects have to be addressed in psychological interventions as well in doctor-patient interactions.