Equivalency of the diagnostic accuracy of the PHQ-8 and PHQ-9: a systematic review and individual participant data meta-analysis

- Wu, Yin; Levis, Brooke; Riehm, Kira E.; Saadat, Nazanin; Levis, Alexander W.; Azar, Marleine; Rice, Danielle B.; Boruff, Jill; Cuijpers, Pim; Gilbody, Simon; Ioannidis, John P.A.; Kloda, Lorie A.; McMillan, Dean; Patten, Scott B.; Shrier, Ian; Ziegelstein, Roy C.; Akena, Dickens H.; Arroll, Bruce; Ayalon, Liat; Baradaran, Hamid R.; Carter, Gregory; Turner, Alyna