Only one in five American adults with opioid use disorder (OUD) receive treatment with medication, according to a new study.

Researchers found buprenorphine, methadone and extended-release naltrexone are vastly underused, NPR reports. The study found women, Black adults, unemployed adults and people living in cities were the least likely to receive medication for OUD.

“Medications for opioid use disorder are safe and effective. They help sustain recovery and prevent overdose deaths,” Nora Volkow, M.D., director of the National Institute on Drug Abuse, which partnered on the study, said in a news release. “Failing to use safe and lifesaving medications is devastating for people denied evidence-based care. What’s more, it perpetuates opioid use disorder, prolongs the overdose crisis, and exacerbates health disparities in communities across the country.”

The researchers said that receiving telehealth treatment for substance use was associated with increased likelihood of medication treatment for OUD. “This finding underscores the growing role telehealth can play in connecting patients with OUD to care,” they wrote.