Risk factors for deliberate self-harm in young people in rural Sri Lanka: a prospective cohort study of 22,000 individuals by Fernando, K, Jayamamanna, S, Weerasinghe, M, Priyadarshana, C, Rohan, R, Pearson, M, Gunnell, D, Dawson, A, Hawton, K, Konradsen, F, Eddleston, M, Metcalfe, C, Knipe, D