Prevalence of Problem Opiate Use
"In 2011, around 10 per cent of OST [Opioid Substitution Treatment] patients report using morphine substances in addition to OST medication during the last 30 days, and 15 per cent have been found to use stimulants. This is a somewhat lower proportion than in 2010. The proportion who have used such drugs in the space of a whole year will be higher. In addition, some people move in and out of OST and may thus have periods of heroin use before, between or after treatment periods during the survey year (Waal et al. 2012)."
Norwegian Institute for Alcohol and Drug Research, "The Drug Situation in Norway 2012: annual report to the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA)," (Oslo, Norway: December 2012), p. 27.