1. Which of the following statements best describes the current state of knowledge on the use of opioid analgesics for the management of chronic (noncancer) pain:
A. There is extensive research supporting their use.
B. There is a moderate amount of research that indicates they are beneficial for this condition.
C. There is extensive research indicating that they provide little benefit for this condition.
D. Virtually no controlled studies have been performed on the use of opioid analgesics for chronic pain.
Chou R, Deyo R, Devine B, et al. The effectiveness and risks of long-term opioid treatment for chronic pain. Evidence Report/Technology Assessment No. 18. Agency for Healthcare Research and Quality; September 2014.