Validation and utility of a self-report version of PRIME-MD - The PHQ primary care study

Context The Primary Care Evaluation of Mental Disorders (PRIME-MD) was deve loped as a screening instrument but its administration time has limited its clinical usefulness. Objective To determine if the self-administered PRIME-MD Patient Health Que stionnaire (PHQ) has validity and utility for diagnosing mental disorders i n primary care comparable to the original clinician-administered PRIME-MD. Design Criterion standard study undertaken between May 1997 and November 19 98. Setting Eight primary care clinics in the United States. Participants Of a total of 3000 adult patients (selected by site-specific m ethods to avoid sampling bias) assessed by 62 primary care physicians (21 g eneral internal medicine, 41 family practice), 585 patients had an intervie w with a mental health professional within 48 hours of completing the PHQ. Main Outcome Measures Patient Health Questionnaire diagnoses compared with independent diagnoses made by mental health professionals; functional statu s measures; disability days; health care use; and treatment/referral decisi ons. Results A total of 825 (28%) of the 3000 individuals and 170 (29%) of the 5 85 had a PHQ diagnosis. There was good agreement between PHQ diagnoses and those of independent mental health professionals (for the diagnosis of any 1 or more PHQ disorder, kappa = 0.65; overall accuracy, 85%; sensitivity, 7 5%; specificity, 90%), similar to the original PRIME-MD. Patients with PHQ diagnoses had more functional impairment, disability days, and health care use than did patients without PHQ diagnoses (for all group main effects, P< .001), The average time required of the physician to review the PHQ was far less than to administer the original PRIME-MD (<3 minutes for 85% vs 16% o f the cases). Although 80% of the physicians reported that routine use of t he PHQ would be useful, new management actions were initiated or planned fo r only 117 (32%) of the 363 patients with 1 or more PHQ diagnoses not previ ously recognized. Conclusion Our study suggests that the PHQ has diagnostic validity comparab le to the original clinician-administered PRIME-MD, and is more efficient t o use.