"Opioid medications present some risk of abuse by patients as well. A structured review of 67 studies found that 3 percent of chronic noncancer pain patients regularly taking opioids developed opioid abuse or addiction, while 12 percent developed aberrant drug-related behavior (Fishbain et al., 2008). A recent analysis revealed that half of patients who received a prescription for opioids in 2009 had filled another opioid prescription within the previous 30 days, indicating that they were seeking and obtaining more opioids than prescribed by any single physician (NIH and NIDA, 2011)."

Source

Institute of Medicine, "Relieving Pain in America: A Blueprint for Transforming Prevention, Care, Education, and Research" (Washington, DC: National Academy of Sciences, 2011), p. 146.
http://www.nap.edu/openbook.p…