"Pain was very prevalent in representative samples of 2 distinct populations with chemical dependency, and chronic severe pain was experienced by a substantial minority of both groups. Methadone patients differed from patients recently admitted to a residential treatment center in numerous ways and had a significantly higher prevalence of chronic pain (37% vs. 24%). Although comparisons with other studies of pain epidemiology are difficult to make because of methodological differences, the prevalence of chronic pain in these samples is in the upper range reported in surveys of the general population. The prevalence of chronic pain in these chemically dependent patients also compares with that in surveys of cancer patients undergoing active therapy, approximately a third of whom have pain severe enough to warrant opioid therapy."
Rosenblum, Andrew, PhD, Herman Joseph, PhD, Chunki Fong, MS, Steven Kipnis, MD, Charles Cleland, PhD, Russell K. Portenoy, MD, "Prevalence and Characteristics of Chronic Pain Among Chemically Dependent Patients in Methadone Maintenance and Residential Treatment Facilities," Journal of the American Medical Association (Chicago, IL: American Medical Association, May 14, 2003), Vol. 289, No. 18, p. 2376.