Understanding the diagnoses and medical care experience of patients with new daily persistent headache: a qualitative study in Spain - Palacios-Cena, Domingo; Talavera, Blanca; Gomez-Mayordomo, Victor; Garcia-Azorin, David; Gallego-Gallego, Maria; Cuadrado, Maria Luz; Guerrero-Peral, angel Luis (Bmj Open, 2021)