Opioids offer little chronic pain benefit and wane over time, study says

(CNN) -- A new report published by the Journal of the American Medical Association shows that opioids offer only slight improvements over a placebo for adults dealing with chronic noncancer pain.

A review of nearly 100 randomized clinical trials also showed that the majority of patients will experience no meaningful benefit from the drugs. The Centers for Disease Control and Prevention describes chronic pain as "lasting longer than 3 months or past the time of normal tissue healing."

It's among the top reasons adults seek medical care in the U.S., affecting just over 20% in 2016 and is a gateway to addiction. In 2016, the CDC issued guidelines urging doctors to prescribe such drugs more responsibly for people with chronic pain.