Yet, with fewer than one in six persons with drug use disorders provided with treatment each year, the availability of and access to science-based services for the treatment of drug use disorders and related conditions remain limited. A significant proportion of the large number of premature deaths among people who use drugs is attributable to opioids. In addition, opioid use disorders account for the heaviest burden of disease attributable to drug use disorders: in 2015, almost 12 million DALYs, or 70 per cent of the global burden of disease attributable to drug use disorders, were attributable to opioids.