Adults ages 50 and older are the largest group seeking treatment for addiction to opioid painkillers and heroin in New York City, according to a new study. People ages 50 to 59 accounted for almost 36 percent of opioid treatment patients in 2012.

In 1996, this age group accounted for only 8 percent of narcotic painkiller and heroin treatment patients, HealthDay reports.

The study found a “pronounced age trend in those utilizing opioid treatment programs from 1996 to 2012, with adults aged 50 and older becoming the majority treatment population,” lead researcher Dr. Benjamin Han of New York University said in a news release.

Patients ages 60 to 69 rose from 1.5 percent to 12 percent between 1996 and 2012, the researchers report in the Journal of Substance Use and Misuse.

“These increases are especially striking, considering there was about a 7.6 percent decrease in the total patient population over that period of time, and suggests that we are facing a never before seen epidemic of older adults with substance use disorders and increasing numbers of older adults in substance abuse treatment,” Han said.

While 56 percent of opioid addiction patients were 40 and younger in 1996, only 20 percent of patients fell into this age group in 2012.

Among patients ages 60 and older, the researchers found a 10 percent increase in whites, a 4 percent increase in Hispanics, and a 14 percent decrease in blacks. Among patients in their 50s, the rate rose 9 percent for Hispanics, 6 percent for blacks and 3.5 percent for whites.

The researchers said they believe the increase in older adults being treated in opioid addiction programs is likely to continue into the next decade. “Opioid dependence is a chronic condition that often needs life-long treatment, and therefore many individuals who are currently in treatment will remain in treatment as they age,” they wrote.