Do engagement and behavioural mechanisms underpin the effectiveness of the Drink Less app? - Claire Garnett; Larisa-Maria Dinu; Melissa Oldham; Olga Perski; Gemma Loebenberg; Emma Beard; Colin Angus; Robyn Burton; Matt Field; Felix Greaves; Matthew Hickman; Eileen Kaner; et al. (npj Digit. Medicine, 2024)