title: Classification characteristics of the Patient Health Questionnaire-15 for screening somatoform disorders in a primary care setting.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: University of Mainz, Department of Clinical Psychology, Germany. stephanie.koerber@uk-erlangen.de
authors.forename: Stephanie
authors.initials: S
authors.lastname: Körber
authors.forename: Dirk
authors.initials: D
authors.lastname: Frieser
authors.forename: Natalie
authors.initials: N
authors.lastname: Steinbrecher
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Hiller
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D010361:Patients / Q000523:psychology*; D011320:Primary Health Care / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012494:Sampling Studies; D013001:Somatoform Disorders / Q000175:diagnosis* / Q000523:psychology*; D011795:Surveys and Questionnaires / Q000592:standards*; D055815:Young Adult