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Patient Health Questionnaire-9 scores do not accurately estimate depression prevalence: individual participant data meta-analysis

Research output: Contribution to journalArticle

Brooke Levis, Andrea Benedetti, J.P.A. Ioannidis, Ying Sun, Zelalem Negeri, Chen He, Yin Wu, Ankur Krishnan, Dipika Neupane, Parash Mani Bhandari, Mahrukh Imran, Danielle Rice, Kira Riehm, Nazanin Saadat, Marleine Azar, Jill Boruff, Pim Cuijpers, Simon Gilbody, Lorie A. Kloda, Dean McMillan & 56 more Scott Patten, Ian Shrier, Roy Ziegelstein, Sultan Alamri, dagmar amtmann, Liat Ayalon, Hamid Baradaran, Anna Beraldi, Charles Bernstein, arvin bhana, Charles H. Bombardier, Gregory Carter, Marcos Chagas, Dixon Chabanda, Kerrie Clover, Yeates Conwell, Crisanto Diez-Quevedo, Jesse Fann, Felix Fischer, Leila Gholizadeh, Lorna J Gibson, Eric D Green, Catherine G. Greeno, Brian J. Hall, Emily E Haroz, Khalida Ismail, Nathalie Jetté, Mohammad Khamseh, Yunxin Kwan, Maria Lara Asunción, Shen-Ing Liu, Sonia Loureiro, Bernd Lowe, Ruth Ann Marrie, Laura Marsh, Anthony Mcguire, Kumiko Muramatsu, Laura Navarrete, Flavia Osorio, Inge Petersen, Angelo Picardi, Stephanie L. Pugh, Terence J. Quinn, Alasdair G. Rooney, Eileen H. Shinn, Abbey Sidebottom, Lena Spangenberg, Pei Lin Lynnette Tan, Martin Taylor-Rowan, Alyna Turner, Henk van Weert, Paul A Vöhringer, Lynne I. Wagner, Jennifer White, Kirsty Winkley, Brett D. Thombs

Original languageEnglish
Pages (from-to)115-128.e1
JournalJournal of Clinical Epidemiology
Early online date24 Feb 2020
Publication statusPublished - Jun 2020

King's Authors


Depression symptom questionnaires are not for diagnostic classification. Patient Health Questionnaire-9 (PHQ-9) scores ≥10 are nonetheless often used to estimate depression prevalence. We compared PHQ-9 ≥10 prevalence to Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders (SCID) major depression prevalence and assessed whether an alternative PHQ-9 cutoff could more accurately estimate prevalence.

Study Design and Setting
Individual participant data meta-analysis of datasets comparing PHQ-9 scores to SCID major depression status.

A total of 9,242 participants (1,389 SCID major depression cases) from 44 primary studies were included. Pooled PHQ-9 ≥10 prevalence was 24.6% (95% confidence interval [CI]: 20.8%, 28.9%); pooled SCID major depression prevalence was 12.1% (95% CI: 9.6%, 15.2%); and pooled difference was 11.9% (95% CI: 9.3%, 14.6%). The mean study-level PHQ-9 ≥10 to SCID-based prevalence ratio was 2.5 times. PHQ-9 ≥14 and the PHQ-9 diagnostic algorithm provided prevalence closest to SCID major depression prevalence, but study-level prevalence differed from SCID-based prevalence by an average absolute difference of 4.8% for PHQ-9 ≥14 (95% prediction interval: −13.6%, 14.5%) and 5.6% for the PHQ-9 diagnostic algorithm (95% prediction interval: −16.4%, 15.0%).

PHQ-9 ≥10 substantially overestimates depression prevalence. There is too much heterogeneity to correct statistically in individual studies.

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