Ostinelli, Edoardo G and Smith, Katharine and Zangani, Caroline and Ostacher, Michael J and Lingford-Hughes, Anne R and Hong, James S W and Macdonald, Orla and Cipriani, Andrea (2022) COVID-19 and substance use disorders: a review of international guidelines for frontline healthcare workers of addiction services. BMC Psychiatry , 22 , (1) .