If the bill to repeal the Affordable Care Act is passed by the Senate and is signed into law, it could impact millions of people’s access to treatment for addiction, experts tell ABC News.

The bill, known as the American Health Care Act, was passed by the U.S. House of Representatives last week. The bill would curb Medicaid expansion, and would change the program’s financing from a matching program to a per capita cap. Experts say this change could lead to a lack of funds to help people with addiction.

In a statement issued in March, the American Society of Addiction Medicine noted that rolling back the Medicaid expansion and changing the program’s financing structure “will certainly reduce access to evidence-based addiction treatment and reverse much or all progress made on the opioid crisis last year.”