Factor structure and longitudinal measurement invariance of PHQ-9 for specialist mental health care patients with persistent major depressive disorder
Boliang Guo,
Catherine Kaylor-Hughes,
Anne Garland,
Neil Nixon,
Tim Sweeney,
Sandra Simpson,
Tim Dalgleish,
Rajini Ramana,
Min Yang,
Richard Morriss
Jul 13, 2018
BACKGROUND: The Patient Health Questionnaire-9 (PHQ-9) is a widely used instrument for measuring levels of depression in patients in clinical practice and academic research; its factor structure has been investigated in various...