Under the American Psychiatric Association’s (APA) new definition of addiction, one-third of patients undergoing long-term pain therapy with opioids meet the criteria for addiction, a new study finds.  Contrary to expectations, the new definition does not reduce the percentage of people considered addicted to opioids.

According to Medical News Today, the findings come from a study of 705 patients undergoing long-term opioid treatment for pain not related to cancer. The researchers compared the APA’s old and new criteria for addiction, and were surprised to find the percentage of patients with addiction to opioids was the same.

Under both the APA’s new and old criteria for addiction, opioid-use disorder was associated with being younger than 65, having a history of opioid abuse and substance abuse treatment, and higher opioid withdrawal symptoms. The study found overall, about 35 percent of patients met the criteria for opioid addiction; 21.7 percent of the patients met the criteria for moderate opioid-use disorder, and 13.2 percent had severe opioid-use disorder. The findings are published in the Journal of Addictive Diseases.