Three-quarters of patients who visit a Detroit emergency room at least 10 times a year—known as “super-frequent” users—have a substance use disorder, a new study finds.

Doctors at Henry Ford Hospital in Detroit also found 47 percent of these patients were addicted to painkillers such as Vicodin and Dilaudid, according to Newswise. Researchers found 44 percent were addicted to other illicit drugs such as cocaine or marijuana, and 35 percent were addicted to alcohol.

The findings were presented at the annual meeting of the Society for Academic Emergency Medicine.

“Emergency departments cannot address the super-frequent users problem without addressing the underlying reason they’re here – their substance abuse problem,” study lead author Jennifer Peltzer-Jones, RN, PsyD, said in a news release. “Boosting federal and state funding for substance abuse programs could help alleviate some of the frequent use of emergency departments as sources of addiction care.”

The federal Drug Abuse Warning Network found an estimated 2.5 million emergency department visits involved drug misuse or abuse in 2011. Between 2009 and 2011, emergency department visits involving overall misuse or abuse increased by 19 percent, or by about 400,000 visits over the two years.

The study included 255 super-frequent users who were cared for at the hospital from 2004 to 2013. In 2004, the hospital created the Community Resources for Emergency Department Overuse (CREDO) to more effectively manage the increased frequent users in the emergency department with individual care plans. The researchers found before CREDO was created, the super-frequent users sought care in the emergency department an average of 32.4 times a year. Since 2004, the rate of super-frequent users who asked for narcotic painkillers in the emergency department decreased to 13.8 times annually.