Somatic Complaints in Primary Care: Further Examining the Validity of the Patient Health Questionnaire (PHQ-15)

The authors examined the reliability and validity of the PHQ-15, a measure of current somatic complaints. An index of medically unexplained symptoms was used as a key criterion. Data were utilized from medical outpatients enrolled in a treatment study for moderate-to-severe somatization (N = 172). Approximately 68% of the sample was Hispanic. Results showed that the PHQ-15 was moderately related to a history of medically unexplained symptoms among non-Hispanic participants. Results indicated ethnic differences on the validity profile of the PHQ-15 showing that the criterion variables were less predictive of the PHQ-15 among Hispanics than among non-Hispanics. Also, among the Hispanic group, the PHQ-15 was less related to medically unexplained symptoms and more to psychiatric distress. General support was provided for using the PHQ-15 with clinical samples composed of non-Hispanics. Also, the PHQ-15 appears to measure medically unexplained symptoms, psychiatric distress, and physical functioning. Further study is recommended to better evaluate ethnic variations and other types of validity for the PHQ-15.