Frequency of somatic symptoms in the general population: Normative values for the Patient Health Questionnaire-15 (PHQ-15).

BACKGROUND: The PHQ-15 is widely used as an open access screening instrument for somatic symptoms in different health care settings. The objectives of the study were to contribute to the construct validity and to generate normative data for the PHQ-15. METHODS: The survey was conducted in the general population in Germany from August 2011 to November 2014 (n=9250). All participants underwent an extensive core assessment including a set of questionnaires. RESULTS: Men reported significantly less (p<0.001) physical symptoms than women (4.6 [SD=3.6] vs. 6.3 [SD=4.1]). The PHQ-15 total score was strongly correlated with the physical component of quality of life (r=-0.58), fatigue (r=0.56), anxiety (r=0.54) and sleep problems (r=0.54). While high socioeconomic status was associated with low prevalences of all complaints, obesity was associated with some of the complaints, especially shortness of breath and pain in arms, legs, and joints. Normative data for the PHQ-15 were generated for men and women. CONCLUSIONS: This investigation confirms the burden caused by somatic symptoms in terms of impaired physical quality of life. In association with psychosocial consequences such as anxiety as well as sleep problems, future studies should also focus on the disease burden of somatic symptoms. In addition, the normative data provide a framework for the interpretation and comparison with other populations.