Lewer, D, Padmanathan, P, Arfeen, MNU, Denaxas, S, Forbes, H, Gonzalez-Izquierdo, A and Hickman, M (2020). Illicit opioid use. [Data Collection]. HDR UK CALIBER Phenotype Library. https://phenotypes.healthdatagateway.org/phenotypes/PH343/version/686/detail/