Locus of control and frequency of physician visits: Results of a population-based longitudinal study in Germany

Objectives. To examine the role of internal and external locus of control (LOC) in the frequency of physician visits longitudinally. Design. A nationally representative, longitudinal cohort study of German households. Data were used from the years 2005 and 2010. Methods. Data were gathered from the German Socio-Economic Panel (GSOEP). The ten internal and external LOC items in the SOEP are based on a scale by Krampen. The number of physician visits in the last 3 months was used as outcome variable. According to Andersen's behavioural model, predisposing characteristics, enabling resources, and need factors were included as control variables. Results. Fixed-effects Poisson regressions showed that physician visits increased with increasing external LOC, whereas changes in internal LOC were not associated with changes in physician visits. Furthermore, physician visits increased with need factors (decreased self-rated health; onset of disability), whereas predisposing characteristics and the enabling resources were not associated with physician visits. Conclusions. Our findings emphasize the meaning of changes in external LOC for physician visits. As there is evidence that interventions can change the LOC, efforts to modify external LOC might be beneficial for the health care system.