Classification characteristics of the Patient Health Questionnaire-15 for screening somatoform disorders in a primary care setting

J Psychosom Res. 2011 Sep;71(3):142-7. doi: 10.1016/j.jpsychores.2011.01.006. Epub 2011 Mar 21.


Background: This study examines how effectively the Patient Health Questionnaire-15 (PHQ-15), a self-administered screening instrument, recognizes somatoform symptoms and somatoform disorders in a German primary care setting.

Methods: A selected sample of 308 patients (mean age 47.2 years, 71.4% women) from two regular primary care practices was screened with the PHQ-15 and additionally examined with structured interviews. Their primary care physicians rated symptoms reported in the interview as either "medically explained" or "medically unexplained."

Results: Seventy-six percent of the symptoms were judged as medically unexplained. The PHQ-15 correlated significantly with the total number of symptoms as well as the number of somatoform symptoms (both r=0.63; P≤.001). A comparison between the most frequently reported symptoms in the interview and the 15 items of the PHQ-15 revealed that even though the PHQ-15 does not differentiate between medically explained and medically unexplained symptoms, it does catch many somatoform symptoms. When used to predict the diagnosis of a somatoform disorder, a cutoff of 10 points in the PHQ-15 was identified as optimal, resulting in a sensitivity of 80.2% and specificity of 58.5%. However, the cutoff has to be adjusted according to specific research or clinical purposes.

Conclusion: Several previous results could be confirmed, and under consideration of some limitations, the PHQ-15 seems to be a valuable tool for identifying somatoform symptoms and disorders in primary care.

Publication types

  • Multicenter Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Female
  • Humans
  • Male
  • Mass Screening
  • Middle Aged
  • Patients / psychology*
  • Primary Health Care* / statistics & numerical data
  • Reproducibility of Results
  • Sampling Studies
  • Somatoform Disorders / diagnosis*
  • Somatoform Disorders / psychology*
  • Surveys and Questionnaires / standards*
  • Young Adult